Course Reference Material
Oracle9iT
Database Administration:
Manage an Instance
NETg course 64311
Copyright © 2002 National Education Training Group, Inc.
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Contents
Objectives
Oracle Architecture Components
Administration Tools
Managing an Oracle Instance
Globalization Support
Glossary
Alphabetical List of Terms
Total number of objectives = 76
Note: (ULT) is the unit, lesson, topic ID.
Oracle Instance and Database
System Global Area (ULT 112): Match the memory structures of the SGA with the information that they store.
Background Processes (ULT 113): Match the mandatory background processes with their functions.
Database Files (ULT 114): Match the different types of files existing in a database with the information that they store.
Database-Related Files (ULT 115): Match database-related files with the information that they store.
Oracle Server: An Introduction
Connecting to an Oracle Server (ULT 121): Match the terms associated with establishing a database connection with their descriptions.
User Processes (ULT 122): Identify the characteristics of a user process.
Server Processes (ULT 123): Identify the characteristics of a server process.
Oracle Security Types (ULT 124): Match the Oracle security types with their functions.
Query Processing
Stages in Processing a Query (ULT 131): Sequence the stages in processing a query.
Shared Pool (ULT 132): Identify the information stored in the shared pool components.
Database Buffer Cache (ULT 133): Identify the characteristics of the database buffer cache.
Buffer Cache Advisory: Overview (ULT 134): Identify the features of the buffer cache advisory.
Program Global Area (PGA) (ULT 135): Match the contents of the Program Global Area with their uses.
DML Statement Processing
Execute Phase of a DML Statement (ULT 141): Identify the steps in the execute phase of a given DML statement.
Rollback Segments (ULT 142): Identify the uses of a rollback segment.
Redo Log Buffer (ULT 143): Identify the characteristics of a redo log buffer.
Database Writer (DBWn) (ULT 144): Identify the events that cause the Database Writer to write to the data files.
Log Writer (LGWR) (ULT 145): Identify the events that cause the Log Writer to write to the redo log files.
Commit Processing
System Change Number (ULT 151): Identify the uses of system change numbers during commit processing.
Commit Processing: Steps (ULT 152): Sequence the steps that occur during the process of commit processing.
Fast Commit Processing: Advantages (ULT 153): Identify the advantages of the fast commit process used by the Oracle server.
Administrative Utilities
Database Administrator Tasks (ULT 212): Identify the tasks of a DBA.
Database Administration Utilities (ULT 213): Match the utilities used by the DBA with the administrative tasks that they enable the DBA to perform.
Universal Installer (ULT 214): Identify the features of the Universal Installer.
Oracle Enterprise Manager (OEM)
OEM Architecture: An Overview (ULT 221): Match the features of the OEM architectural components with their functions.
OEM Console Components (ULT 222): Match the OEM Console components with the tasks that they perform.
OEM Common Services (ULT 223): Match the OEM services with their tasks.
Setting Up OEM (ULT 224): Sequence the steps performed to set up OEM for use.
Management Packs
DBA Management Pack (ULT 231): Match the OEM DBA Management Pack applications with the tasks that they enable you to perform.
Additional Management Packs (ULT 232): Match the components in the additional management packs with their functions.
Authentication and Privileges
Database Administrator Users (ULT 312): Identify the characteristics of the default DBA user accounts.
Setting Up OS Authentication (ULT 313): Set up an NT log on to the Oracle database without a password by using NT User Manager.
Remote_Login_Passwordfile: Parameters (ULT 314): Match the REMOTE_LOGIN_PASSWORDFILE parameters with their functions.
Setting Up Password File Authentication (ULT 315): Set up a password file authentication on an NT platform by using the ORAPWD utility.
Changing the Internal Password (ULT 316): Change the SYS password by using the ORAPWD utility.
Parameter File
Parameters in the Parameter File (ULT 321): Identify the uses of the parameters included in the parameter file.
Rules for Parameter Values (ULT 322): Identify the rules that govern the parameter values specified in the parameter file.
Essential Parameters (ULT 323): Identify the essential parameters for an Oracle instance.
Undo Mode: Initialization Parameters (ULT 324): Match the undo mode initialization parameters with their functions.
License Parameters (ULT 325): Match the license parameters with their functions.
Commonly Modified Parameters (ULT 326): Identify the commonly modified parameters of a parameter file.
SPFILE Parameter
SPFILE: Overview (ULT 331): Identify the features of SPFILE.
SPFILE: Creating (ULT 332): Identify the guidelines that you use to create an SPFILE.
SPFILE and Real Application Clusters (ULT 333): Identify the features of SPFILE in Real Application Clusters.
Instance Startup and Shutdown
Instance Startup: Stages (ULT 341): Match the stage of instance startup with the correct description.
Starting An Instance: Scenarios (ULT 342): Identify the methods that are used to start an instance.
Starting an Instance (ULT 343): Start an Oracle instance by using the OEM Console.
Changing Database Availability (ULT 344): Change a database state by using the OEM Console.
Database Quiescing: Features (ULT 345): Identify the features of a quiesced database state.
Instance Shutdown: Stages (ULT 346): Match the shutdown stages with the tasks performed in each stage.
Shutdown Modes (ULT 347): Identify the conditions with which the instance is shutdown in each shutdown mode.
Dynamic Performance Views
Dynamic Performance Views: Features (ULT 351): Identify the features of the dynamic performance views.
V$SPPARAMETER View (ULT 352): Match the columns of the V$SPPARAMETER view with the data they store.
Dynamic Performance Views: Descriptions (ULT 353): Match the associated dynamic performance view with a given description.
Dynamic Parameters
Displaying Current Parameter Values (ULT 361): Display the current parameter values by using the V$PARAMETER dynamic performance view.
Dynamic Buffer Cache: Parameters (ULT 362): Match the dynamic buffer cache parameters with the values they store.
Dynamic Initialization Parameters (ULT 363): Modify a dynamic initialization parameter by using the OEM Console.
Managing Sessions
Enabling Restricted and Read-Only Modes (ULT 371): Change the database mode by using the OEM Console.
Terminating Sessions (ULT 372): Terminate a user session by using the OEM Console.
Diagnostic Files
Diagnostic Files: Difference (ULT 381): Identify the differences between an alert file and a trace file.
Trace File: Parameters (ULT 382): Match the trace file parameters with the values that they store.
Alert Files (ULT 383): Identify the information stored in a given alert file.
Character Sets
Globalization Features (ULT 412): Identify the features of Globalization Support..
Character-Encoding Schemes (ULT 413): Match the character-encoding scheme classes with their descriptions.
Character Set Features (ULT 414): Identify the features of the character sets.
Language-Dependent Behavior
Globalization Parameters: Server Side (ULT 421): Identify the combinations of the Globalization Support parameters used for specifying the default conventions and session 14414b11o characteristics.
Derived Globalization Parameters (ULT 422): Match the derived Globalization Support parameters with their descriptions.
Overriding the Default Behavior (ULT 423): Override the default Globalization Support behavior for an individual session by using the NLS_LANG environment variable.
Language-Dependent Behavior for a Session (ULT 424): Change the Globalization Support settings for a session by using the ALTER SESSION command.
Globalization and Sorting (ULT 425): Specify the linguistic sort type by using the NLS_SORT parameter.
Globalization Parameters: SQL Functions (ULT 426): Identify the SQL statement that uses an SQL function and a Globalization Support parameter to generate the given output on its execution.
Data Conversion and Migration
Semantics: Overview (ULT 431): Identify the features of various semantics.
Data Scanning Tests (ULT 432): Select the tests that are performed on data during the scan.
Scanner Process Invocation: Steps (ULT 433): Identify the steps that are used in the scanning process.
Data Dictionary Information
Obtaining Information on Character Sets (ULT 441): Retrieve the character sets for the database by using the NLS_DATABASE_PARAMETERS view.
Globalization Setting: Information (ULT 442): Retrieve information about Globalization Support settings by using views.
To enter or communicate with a particular computer resource, such as an operating system, an Oracle database, or specific files or tables. Various commands or controls are used to set and alter the resources, depending on the type of resource.
One of several types of privileges, such as SELECT, ALTER, or DROP, for using or altering Oracle database objects such as tables, views, or indexes. Database users can grant other users access via the GRANT statement.
The process of limiting access to the resources of a system only to authorized programs, processes, or other systems.
A list of privileges associated with every directory and file that specifies the type of access allowed for any user.
The algorithm used by the Oracle server to locate data within a database. When the optimizer parses a SQL statement, it evaluates possible access paths in order to use the best access path. To some degree, users can help the optimizer choose an access path through deliberate wording of SQL statements.
An authorized user of an operating system or a product (such as the Oracle server). Depending on the operating system, the account may be referred to as an ID, User ID, or login. Accounts are often created and controlled by a system administrator. See also schema, username.
Active Session Pool
Control the maximum number of concurrently active sessions that are allocated to the resource consumer group. Once the pool is filled, the server queues up all of the sessions that are attempting to become active.
A unique network location used to identify a client on a network. TNS addresses have a specific format. Addresses must be unique.
The authorization to perform certain administrative procedures on a system.
A modal window with a limited interface that warns the user that the action immediately preceding the alert may cause unexpected results. An alert displays a brief message and requires a response. Also known as an alert box.
If an error occurs while the Oracle instance is running, the messages are written to the ALERT file. The ALERT file of a database is a chronological log of messages and errors. ALERT files are used to check whether or not an instance is running properly.
An alternative name for an existing network object, such as a host (server) or a set of parameters.
In SQL, an alias is a temporary name assigned to a table, view, column, or value within a SQL statement, used to refer to that item later in the same statement or in associated SQL*Plus commands. In Net8, an alias is a nickname for a string by which a remote database can be accessed.
A category of the data dictionary views that provides information about the objects to which a user has access through publicly or explicitly granted roles and privileges. ALL_views also contains information about the objects that a user owns.
A set of program functions or calls that allows an application to make use of, or communicate with, an underlying program or system.
One or more program modules used to achieve a specific result. Applications can be nested within other applications. For example, an application to control a company's inventory could consist of various Form Builder applications for input of data, and various Report Builder applications to produce hard copy output of summary data.
Process that copies the online redo log files to archival storage at a Log Switch. ARCn is active only when a database is in ARCHIVELOG mode. This is one of many background processes that are part of an Oracle instance. See also background process, Log Switch, redo log.
To save data for later use.
An ASCII character set is a convention for representing alphanumeric information using digital data. ASCII is the collation sequence used by most computers with the exception of IBM and IBM-compatible computers. See EBCDIC character set.
The result of the auditing activity.
Data, in the form of a logical path linking a sequence of events, used for tracing the transactions that have affected the contents of a record.
The process of recording or analyzing operations that have been performed on a body of data.
An Oracle server feature that enables a database administrator to monitor user activity on a database. Auditing information is stored in the data dictionary and SQL statements are used to control which information is stored.
The process of verifying the identity of a user, device, or other entity in a computer system, often as a prerequisite to allowing access to resources in a system.
Permission given to a user, program, or process to access resources.
A SQL*Plus feature that optionally requests an automatic commit after every successful execution of a SQL statement or PL/SQL block.
An indexing structure used by the Oracle server to create and store indexes. The structure is named after the indexing algorithm used.
The creation of a copy (or copies) of existing data to enable recovery of that data if required.
A high-capacity network that links smaller or slower networks.
A non-interactive process that runs in an operating system environment and performs some service or action. Certain Oracle products use background processes for different tasks, such as performing and coordinating tasks on behalf of concurrent users of the database, processing and delivering electronic messages, and managing printing services.
The result of backup activity.
The BACKGROUND_DUMP_DEST parameter specifies the location to which a background process writes the TRACE files.
An output file created by SQL*Loader. It contains the records that were rejected during the load.
A set of underlying tables that store information about an associated database object. Base tables are generally used to represent a table on which a view is built.
Users specify a query to run automatically if they do not want to stop work to wait for the results. The computer decides when to run the query. Users can go back and look at the results of the query later.
LOBs are stored in separate segments within the database by using external binary files (BFILES).
A subdirectory of the Orant directory that contains the binary files for all the Oracle products and databases on the system.
A datatype that stores large binary objects in a database in-line or out-of-line.
The basic unit of physical or logical storage. The size of an Oracle block may differ from the block size native to the operating system. Typical Oracle block size is 2048 bytes. The terms page and block are often used synonymously.
In PL/SQL, a group of SQL and PL/SQL commands related to each other through procedural logic.
Used in search statements to combine search terms. Usual operators are AND, OR, and NOT.
In the Oracle database, a small segment used during instance startup to populate the dictionary cache.
An event, such as a change in the value of an expression, that may occur while SQL*Plus processes a query or report. You can direct SQL*Plus to perform various operations, such as printing subtotals, whenever specified breaks occur.
A temporary storage area for data during the transfer of that data between the computer and a peripheral, or between parts of a computer. A buffer prevents loss of information due to differences in the speed, or timing of the transfer, and speeds up certain functions.
(database) Temporary storage place in the SGA for database blocks currently being accessed and changed by database users. Each block undergoing change must be stored in a buffer. By caching blocks in memory, performance is enhanced because reading blocks from memory is faster than reading them from disk.
(redo log) Temporary storage place where redo log records are created and held before being written to the redo log file.
In Net8, an area of memory used by the network driver to pass data between two points on the network.
In SQL*Plus, an area where the user's SQL statements or PL/SQL blocks are temporarily stored. The SQL buffer is the default buffer although multiple buffers can be used.
buffer cache advisory
This feature enables and disables you to collect statistics. You use these statistics to predict the behavior with different cache sizes. These statistics provide information that can help DBAs size the buffer cache optimally for a given workload.
A temporary storage place for database data that is currently being accessed or changed by users, or for data that Oracle server requires to support users. See also buffer (database). The terms cache and buffer are often used interchangeably.
An automatic process that occurs when one object is deleted. In this instance, all the subordinate objects (and their subordinates, and so on) are also deleted.
An automatic process that occurs when a primary key or a unique identifier of an object has its value changed. In this instance, all related objects that explicitly quote the original value have their values changed to reflect this new value. Similarly, cascade update may also refer to derived data and controlled replication of any data.
At the time of its creation, the SYS user account is given the password CHANGE_ON_INSTALL.
An Oracle datatype used to define a fixed-length column that can contain any printable characters, such as A, 3, &, or blanks, and can have from 1 to 255 characters or can be null. See datatype.
In Form Builder, a field whose value is a sequence of characters.
A single location on a computer system capable of holding one alphabetic character or numeric digit. One or more characters are held in a field. One or more fields make up a record, and one or more records may be held in a file or database table.
The format of an attribute, which may contain alphabetic characters or numeric digits.
An encoding scheme that specifies numbers corresponding to each character that the character-mode workstation can display.
A group of sequential letters, numerals, or symbols, usually comprising a word or name, or a portion thereof.
A set of rules that govern whether a value can be updated or deleted.
At specific times, all modified database buffers in the SGA are written to the data files by DBWn; this event is called a checkpoint. The checkpoint process (CKPT) is responsible for updating all the data files and control files of the database to indicate the most recent checkpoint event.
An error-checking algorithm.
An object that is a member of a group, and is immediately below that group object in its group tree. The objects that compose a group object are children of that group. Every object is a child of its parent.
A part of a SQL statement that does not constitute the full statement; for example, a WHERE clause.
A user, software application, or computer that requests the services, data, or processing of another application, or computer (the server). In a two-task environment, the client is the user process. In a network environment, the client is the local user process and the server may be local or remote. See also server process.
Software architecture based on a separation of processing between two CPUs, one acting as the server that provides services in a transaction and the other as the client in the transaction, requesting and receiving services. This architecture allows for separate processing between the database server and the client application programs. All responsibilities of shared data management can be processed by the computer running the database management system while the workstations running the database application concentrate on the interpretation and display of data. See also client, distributed processing, and server process.
A LOB datatype that enables you to store up to four gigabytes of character data in the database. CLOB datatypes store single-byte character set data. See datatype.
A database that is associated with an instance, but is not open. A database must be mounted and closed for the DBA to perform certain database maintenance tasks. A database is mounted and opened using the SQL statement ALTER DATABASE.
A database structure in which one or more tables are stored together in the same block. A cluster allows tables that contain common information to be accessed concurrently. Tables that are clustered have one or more columns in common and are frequently referenced together in queries (especially joins). See also cluster index and cluster key.
In network communication, a configuration in which two or more terminals are connected to a single line or single modem.
The related columns of the tables in a cluster.
An index manually created after a cluster of database tables has been created. The index must be created before any DML statements can operate on the clustered tables. The index is created on the cluster key with the SQL statement CREATE INDEX.
The related column of the tables in a cluster. The cluster key is indexed so that rows of the cluster can be retrieved with a minimum amount of I/O. Because the data in a cluster key of an index cluster (a non-hash cluster) is stored only once for multiple tables, clusters may store a set of tables more efficiently than if the tables were stored individually (not clustered).
A vertical space in a database table that represents a particular domain of data. A column has a column name and a specific datatype. For example, in a table of employee information, all of the employees' dates of hire would constitute one column. A record group column represents a database column.
In the context of CASE, a table is often the implementation of an entity. The columns of the table are used to implement the attributes of the entity and its relationships.
An expression in a SELECT statement that defines which database columns are retrieved. It may be a column name or a valid SQL expression referencing a column name.
An instruction to, or request from, a program, application, operating system, or other software, to perform a particular task. Commands may be single words or may require additional phrases, variously called arguments, options, parameters, and qualifiers. Unlike statements, commands execute as soon as you enter them.
A file containing a sequence of commands that you can otherwise enter interactively. The file is saved for convenience and re-execution. Command files are often called by operating-system specific names, such as COM files, DCL files, EXEC files, or BAT or CLI files.
A line on a computer display on which typed-in commands appear. An example of a command line is the area next to the DOS prompt on a personal computer.
To make permanent changes to data (inserts, updates, deletes) in the database. Before changes are committed, both the old and new data exist so that changes can be stored or the data can be restored to its prior state.
In Form Builder, to store new or changed records from the workspace into a table in the database.
An index (or key) value for a database table that is formed by more than one column. Composite key columns are used in concatenated indexes. See also key and concatenated index.
An index (or key) that is created on more than one column of a table.
An expression whose value is either true or false, such as X > 100. You add a condition to a query when you want the query to display only those rows that evaluate as true in your expression.
Files that are used to identify and characterize the components of a network. Configuration is largely a process of naming network components and identifying relationships among those components.
To access an Oracle or foreign database using a valid username and password. Connecting to a database is similar to logging on to an operating system using an account name and password. You must connect if you want to create or modify queries or access a display stored in a database.
The set of parameters, including a protocol, that Net8 uses to connect to a specific Oracle instance on the network.
A communication pathway between a user process and the Oracle server is called a connection.
A database requirement that all related data be updated together in the proper order, and that redundant data values agree. Consistency ensures that the data a user is viewing or changing is not changed (by other users) until the user is finished with the data.
A rule or restriction concerning a piece of data, such as a NOT NULL restriction on a column, that is enforced at the database level, rather than the object or application level. See also check constraint.
A PL/SQL code structure. There are two types of constructs: non-value constructs do not return a value; value constructs return a value.
An administrative file that is required to start and run a database system. The control file records the physical structure of the database. For example, a control file contains the database name, names and locations of a database's data files and redo log files, and the time stamp of database creation. The use of multiple identical control files is strongly recommended for protection of the file. During normal recovery procedures, the information in a database's control file is used to guide the automated progression of the recovery operation.
A file specifying the input format, the output tables, and the optional conditions for a load performed using SQL*Loader.
An initialization parameter that specifies the path of control files of a database.
To bring an object (a table, block, field, and so forth) into existence, usually by defining its primary characteristics. See also define.
The process of making a database ready for initial use. Includes preparing the database files and creating data dictionary tables required by the Oracle server. Database creation is accomplished using the SQL statement CREATE DATABASE.
A database data storage unit at the finest level of granularity. One data block corresponds to a specific number of bytes of physical database space on disk. A data block size is specified for every Oracle database when the database is created. A database block is the minimum unit of I/O used by an Oracle server.
The category of SQL statements that control access to the data and to the database. Examples are the GRANT and REVOKE statements. Occasionally DCL statements are grouped with DML statements.
The category of SQL statements that define or delete database objects such as tables or views. Examples are the CREATE, ALTER, and DROP statements.
A comprehensive set of tables and views automatically created and updated by the Oracle server, which contains administrative information about users, data storage, and privileges. It is installed when Oracle is initially installed and is a central source of information for the Oracle server itself and for all users of Oracle. The tables are automatically maintained by Oracle. It is sometimes referred to as the catalog.
Files that contain all the database data. A data file is associated with only one database. The contents of logical database structures, such as tables and indexes, is physically stored in the data files allocated for a database. One or more data files form a logical unit of database storage called a tablespace.
Files containing the input records to be processed during a load performed using SQL*Loader.
The category of SQL statements that changes the database data. Common DML statements are INSERT, UPDATE, and DELETE. Occasionally queries and DCL statements are grouped with DML statements.
The mechanisms that control the access and use of the database at the object level. For example, data security includes access to a specific schema object and the specific types of actions allowed for each user on the object (e.g., user SCOTT can issue SELECT and INSERT statements but not DELETE statements using the EMP table). It also includes the actions, if any, that are audited for each schema object.
A type of target system where data is either manipulated using a non-procedural language, such as SQL, or where the data manipulation can be mapped in a non-procedural manner.
A set of operating system files, treated as a unit, in which an Oracle server stores a set of data dictionary tables, user tables, and other objects needed to store and manage data. A database consists of three types of files: database files, redo log files, and control files.
The disk space corresponding to database files, redo log files, and control files.
A person responsible for the operation and maintenance of an Oracle server or a database application. The database administrator monitors the database use in order to customize the database to meet the needs of the local community of users.
An Oracle role that has been given the privileges needed to perform database administration functions. There may be more than one DBA per site.
Buffers that store the most recently used blocks of database data; these buffers can contain modified data that has not yet been permanently written to disk. By storing the most recently (often the most frequently) used data in memory, less disk I/O is necessary, thus increasing database system performance.
A file reserved for the storage of database objects, such as the data dictionary, user tables, and indexes. At least one database file is required for each Oracle database system; more can be added at any time.
A set of structures used to access an Oracle database. There is usually a one-to-one correspondence between an Oracle instance and a System Global Area (SGA). An instance consists of an SGA and several background processes.
A unique identifier used to name a database. It is assigned in the CREATE DATABASE statement or in the INIT.ORA file.
Something created and stored in a database. Tables, views, synonyms, indexes, sequences, clusters, and columns are all examples of database objects.
The node or computer at which the Oracle server kernel runs. The database server holds the database, runs the Oracle server kernel, is not an MS-DOS PC or Macintosh (but could be an OS/2 PC), and runs a multitask operating system.
A process that writes modified blocks from the database buffer cache to the data files. Because of the way Oracle performs logging, DBWn does not need to write blocks when a transaction commits. Instead, DBWn is optimized to minimize disk writes; in general, writes occur only when more data needs to be read into the SGA and there is too little free space in the database buffers.
A set of tables and views used as a reference to provide updated information about a database.
A view on the data dictionary tables created to facilitate retrieving information about a database.
Data Scanning
The data scanning utility is used to examine the database for possible data conversion areas. Data conversion is used to migrate the database character set.
A standard form of data. The Oracle datatypes include CHAR, DATE, NUMBER, VARCHAR2, and BLOB. However, the Oracle server recognizes and converts other standard datatypes.
A named set of fixed attributes that can be associated with an item as a property. Data typing provides a way to define the behavior of data.
A standard Oracle datatype used to store date and time data. The default date format is determined by the national language support (NLS) setting. A DATE column may contain a date and time between January 1, 4712 BC to December 31, 9999 AD. See national language support (NLS).
A role given to a user via the GRANT DBA statement. The DBA role should be limited to very few users.
A category of the data dictionary views that provide information about all database objects.
An initialization parameter that specifies the number of database buffers available in the database buffer cache. This parameter is of the integer type.
An initialization parameter that specifies the size of the Oracle database blocks in bytes. The value of the DB_BLOCK_SIZE parameter is used to determine the size of the blocks when the database is created. This parameter is of the integer type.
DB_CACHE_ADVICE
You can enable the buffer cache advisory by using this initialization parameter. You can set the parameter to OFF, ON, or READY values.
DB_CACHE_SIZE
This parameter specifies the size of the DEFAULT buffer pool for buffers with the primary block size.
DB_KEEP_CACHE_SIZE
The parameter specifies the number of buffers in the KEEP buffer pool. The KEEP buffer pool retains the schema object's data blocks in memory. The size of the buffers in the KEEP buffer pool is the primary block size.
An initialization parameter that specifies the name of the database.
An Oracle-supplied package that provides routines for performing operations on large objects.
DB_RECYCLE_CACHE_SIZE
You can use this parameter to specify the size of the RECYCLE buffer pool. The RECYCLE buffer pool eliminates data blocks from memory as soon as they are no longer needed. The size of buffers in this pool is the primary block size.
An Oracle-supplied package that provides functions that convert Oracle7 restricted format ROWIDs to Oracle8 extended format ROWIDs, and vice versa.
An Oracle-supplied package that generates SQL commands such as ALTER SESSION or SET ROLE. The DBMS_SESSION package is defined by the dbmsutil.sql and prvtutil.sql scripts.
An Oracle-supplied package that enables a DBA to keep objects in the shared pool so that they do not age out with the least recently used (LRU) algorithm.
An Oracle-supplied package that provides information about the availability of segment space.
An Oracle-supplied package that provides various utility routines that enable you to analyze and compile a schema and resolve names. The DBMS_UTILITY package also provides functions for time management and obtaining addresses and error stacks.
One of five background processes used by multiple-user database systems. The Database Writer (DBWn) process writes new data (modified blocks) from the database buffer cache to the data files. Because of the way Oracle performs logging, DBWn is optimized to minimize disk writes; in general, writes occur only when more data needs to be read into the SGA and there is too little free space in the database buffers.
A situation in which two or more users of a database cannot complete their transactions because each user is holding a resource that the other user requires. The Oracle server automatically avoids and resolves deadlocks.
A value supplied by the system when a user does not specify a required command parameter or qualifier.
While starting an application, the default database is the database to which the application will be connected when no connect string is included in the logon string.
After starting an application, the default database is the database to which the application is already connected. See local database.
When a user creates a table, index, or cluster and no tablespace is specified to physically contain the object, the user's default tablespace is used. This assumes that the user has the privilege to create the object and a quota in the specified default tablespace. The default tablespace feature provides Oracle with information to direct space usage in situations where object location is not specified.
A rollback segment containing rollback entries that could not be applied to a tablespace because that tablespace was since taken offline. As soon as the tablespace is brought back online, all the entries are applied.
To specify the properties of an object (a table, block, field, and so forth). See also create.
To remove a row from a table using the SQL statement DELETE.
A partial screen that prompts you to enter some piece(s) of information necessary to complete an operation. Dialog boxes are accessed extensively via the File menu and buttons. A dialog box typically requires more information from the user than an alert.
One of several caches contained in the SGA used for storing data dictionary information. The data dictionary information is constantly referenced. Accordingly, this cache improves Oracle server performance.
A category of locks acquired on behalf of users who are parsing statements (shared dictionary locks) or executing DDL statements (exclusive dictionary locks). Shared dictionary locks are synonymous with parse locks, and exclusive dictionary locks are synonymous with DDL locks.
A method of loading data from one table to another table within the same database.
A special type of file that catalogs information about subordinate files. Use directory files to organize a hierarchical file structure.
An output file created by SQL*Loader. The discard file stores all the records that did not satisfy the selection criteria.
An area on a disk that contains 512 bytes of data.
A database that is not mounted by any instance, and thus cannot be opened and is not currently available for use.
A Net8 network where data is delegated to multiple administrative regions.
A blueprint or specification that enables applications to access data on more than one CPU (and often many types of computers ranging from PCs to mainframes) within a computer system or network.
A single, logical database that is physically located on two or more computers, connected via some form of communications network. An essential feature of a true distributed database is that the user and/or program work as if they had access to the whole database locally. All processing to give this impression is carried out by the database management system. See also distributed processing.
A system that combines the data physically located on different computers into one logical database that can be accessed by all network users in computing environments that are connected via networks. Distributed systems have the same degree of user transparency and data consistency as undistributed systems, yet receive the advantages of local database management.
The use of more than one processor to divide the processing for a set of related jobs. Distributed processing reduces the processing load on a single processor by enabling different processors to concentrate on a subset of related tasks, thus improving the performance and capabilities of the system as a whole. An Oracle database system can easily take advantage of distributed processing by using its client-server architecture. In this architecture, the database system is divided into two parts: a front-end or a client portion and a back-end or a server portion. Net8 supports distributed processing by transparently connecting applications to remote databases. Different from, but often confused with, distributed database. See also remote database.
A standard Oracle database table named DUAL, which contains exactly one row.
A file created when a problem or exceptional condition is encountered while using a software program. Also called a trace file, the file contains information useful in diagnosing or locating the problem.
A set of views that are maintained by the server and accessible to the database administrator user SYS. These views are called dynamic performance views because they are continuously updated while a database is open and in use.
An EBCDIC character set is a convention for representing alphanumeric information using digital data. The collation sequence is used by IBM and IBM-compatible computers. See ASCII character set.
A message from a computer program informing you of a potential problem or condition preventing program or command execution.
A lock that gives the owner of the lock sole use of the locked resource. Other users may only query the locked data; they may not change it until the exclusive lock is released. Contrast with share lock.
An Oracle instance running in exclusive mode has sole access to the database; no other instances can mount or open the database files. A distributed lock that an instance holds in exclusive mode gives the instance sole access to the data or other resource covered by that lock.
A phase of SQL statement execution. After all the information necessary for execution is obtained, the statement is executed.
Locking that occurs because a user has used the SQL statement, such as LOCK TABLE, in order to specify the exact type of lock to be obtained. Contrast with implicit locking.
The files comprising an export, or the act of performing an export.
To write database data to files for the purpose of archiving, or moving data between operating systems or Oracle databases.
An Oracle utility used to write database data to operating system files external to the database. These files can then be used with the Import utility.
A formula, such as SALARY + COMMISSION, used to calculate a new value from existing values. An expression can be made up of column names, functions, operators, and constants. Formulas are found in commands or SQL statements.
A specific number of contiguous data blocks, obtained in a single allocation, used to store a specific type of information. An extent can be allocated when the table or index is created or when the table or index requires additional space. See also segment.
A phase of query execution, where rows of data that meet all search criteria are retrieved from the database.
A place in a window within a tool where a value can be entered.
A collection of data treated as a unit, such as a list, document, index, note, set of procedures, and so forth. Generally used to refer to data stored on magnetic tapes or disks. See also filename.
The name component of a file specification. A filename is assigned by either the user or the system when the file itself is created.
A character set that contains all of the characters of a certain width, which belong to a corresponding varying-width multibyte character set.
One or more columns in one data source whose values refer to the primary key values in another data source. See also primary key.
fragmentation
A database with many non-contiguous, small blocks of free space is said to be fragmented.
A database file in which free space (unused blocks) is in many small pieces rather than fewer large pieces. This is a common result of much database activity. Fragmentation can cause less efficient space usage, but is easily fixed by exporting and importing data.
Database blocks that are not currently allocated to any table or index segment. Also called free space.
Required clause of the SELECT statement that identifies the tables or views from which data is selected.
An operating system backup of all data files, online redo log files, and the control file that constitutes an Oracle database. Full backups are performed when the database is closed and unavailable for use.
A PL/SQL subprogram that executes an operation and returns a value at the completion of the operation. A function can be either built-in or user-named. Contrast with procedure.
A facility to enable users to have certain access rights to information in a database.
The option to pass on the object privileges that you have been granted to other database users. This option is granted using the SQL statement GRANT WITH GRANT OPTION.
Cluster table data similar to normal index clusters. However, a row is stored in a hash cluster based on the result of applying a hash function to the row's cluster key value. All rows with the same hash key value are stored together on disk. Hash clusters are a better choice than using an indexed table or index cluster when a table is often queried with equality queries (e.g., return all rows for department 10). For such queries, the specified cluster key value is hashed. The resulting hash key value points directly to the area on the disk that stores the specified rows.
A function used in a hash cluster to calculate the location of a row.
Hashing
This is an optional way of storing table data in a hash cluster to improve the performance of data retrieval. Oracle uses a hash function to generate a distribution of numeric values, called hash values. These hash values are based on specific cluster key values. Oracle uses these key values as though they are indexes to retrieve data.
Term used to describe networks running different communications protocols and different media.
Term used to indicate the last block a segment used for storing data. It is reset only when the segment is truncated.
A computer that provides a shared resource on a network.
The name or alias of the host system to which you want to connect.
A file used by most commercially available implementations of TCP/IP that identifies the Internet addresses of the available hosts on the network.
The process that enables recognition by the system, such as providing a username.
Locking that is performed automatically by the Oracle server on behalf of the user. Contrast with explicit locking.
An Oracle utility that reads operating system files, written by Export, to restore the data to an Oracle database.
A tree-like structure that allows direct access to a row in a table. Indexes can be classified on the basis of either their logical design or their physical implementation.
The process whereby the index for a table is created.
A cluster that uses a specifically defined index, known as the cluster index, to maintain the data within the cluster.
An operating system file containing a list of parameters that are read when an instance is started. The parameters identify the database and control instancewide resources. By affecting the size of the SGA, they also affect the performance of the instance. In UNIX, the init.ora file.
A table that stores all the data within an index structure. Row data in an IOT is ordered on the basis of the primary key of the table.
The initialization parameters specify the characteristics of the Oracle instance
File containing data to be transferred into the computer.
The background processes and memory areas required to access an Oracle database. A database system requires one instance and one database. Every Oracle instance has a single System Global Area (SGA); a multiple-user instance also requires several background processes.
Failure that occurs when a problem arises that prevents a database instance (SGA and background processes) from continuing work. Instance failure may result from a hardware problem, such as an outage, or a software problem, such as an operating system crash. When an instance failure occurs, the data in the buffers of the SGA is not written to the data files.
A name or ID used to distinguish one instance from another when multiple instances exist on one machine. The identifier is specified in an operating-system specific manner.
Recovery of an instance in the event of software or hardware failure so that the database is again available to users. If the instance terminates abnormally, then instance recovery automatically occurs at the next instance startup. See also media recovery.
(data) The accuracy, consistency, and security of database data, as maintained by the Oracle server throughout all user access.
The intelligent agent is a process that runs on the remote nodes in a network. The intelligent agent executes the jobs and events that are sent by the OEM Console.
INTERNAL is a username that the DBA can use to connect to a V6 database in rare situations, such as database creation. It requires special operating system privileges.
General category of locks on internal database structures and physical files. Internal locks include dictionary cache locks, file and log management locks, and tablespace and rollback segment locks.
A network made up of two or more subnets.
In TCP/IP, a number that identifies the address for a node on the network.
The ability of programs on different, multivendor computers to share data. Interoperability requires process-to-process networks that follow the same communication protocols at all levels, from client/server programs to the wire.
An invalid object is an object that is marked for recompilation or revalidation when referenced. It cannot be used if any of the objects it depends on are not accessible.
An organization that specifies new networking standards. Not to be confused with OSI, which is the Open Systems Interconnect model put forth by the organization.
A query that retrieves data from multiple database tables, specifying how rows are to be related using a join condition. Occasionally one table is joined to itself. See also self-join.
The core software that runs the Oracle server.
A word that has a specific meaning in a computer language, such as SQL, and therefore cannot be used except in that context.
A unit of computer memory equal to 1024 bytes, often rounded off to 1,000 bytes.
In an index, a node that has no children rows. The lowest-level node, or the node at the finest level of detail.
A scheme that ages out the least recently used data blocks from the database buffer cache or shared pool to make way for new data blocks. This algorithm attempts to retain the most frequently used data or statements in the SGA.
One of five background processes used by an Oracle instance. Log Writer writes redo log entries to disk. Also called LGWR process.
LICENSE_MAX_SESSIONS
This parameter depicts the maximum number of concurrent user sessions that are allowed. When the session reaches this limit, only users with the RESTRICTED SESSION privilege can connect to the database
LICENSE_MAX_USERS
This parameter specifies the maximum number of users that you can create in the database. When you reach this limit, you cannot create more users.
LICENSE_SESSIONS_WARNING
This parameter specifies a warning limit on the number of concurrent user sessions. When this limit is reached, additional users can connect but Oracle server writes a message in the alert file for every new connection.
Term used to describe a segment that stores large objects (LOBs), such as images, in the database.
A limited-distance, high-speed, data communications network that allows various data processing resources to be connected and shared. Typically served by communications media such as Token Ring and Ethernet. LANs are usually less expensive, easier to maintain, and offer better performance than WANs.
The database on the computer running the application.
The database to which an application is connected. This database parses and executes all SQL statements generated by the application. Contrast with remote database.
A table that resides in the database to which the user is connected.
(noun) A temporary hold on a database resource, acquired by a user while using that resource, to support concurrency. A lock is a mechanism intended to prevent destructive interaction between users accessing Oracle data. Destructive interaction can be interpreted as any interaction that incorrectly updates data or incorrectly alters underlying data structures. Locks are used to achieve consistency and integrity. There are numerous types of locks; see dictionary locks.
(verb) To request a lock on a database table or row with the SQL statement LOCK, in order to temporarily restrict other users' access to it and to perform updates or queries.
A parameter that specifies the amount of memory to be allocated for the redo log buffer that is used to cache redo log entries within the SGA before they are written to the redo log files. The amount of memory specified is in bytes.
An output file created by SQL*Loader that contains a record of the load.
To perform a sequence of actions at a workstation that establishes a user's communication with the operating system and sets up default characteristics for the user's session.
Login Server
The Login Server is a component of Oracle Portal 3.0 in Oracle9i Application Server. This server extends the single sign-on capabilities to Web based and external applications
To terminate interactive communication with the operating system, and end a session.
A unique number identifying a specific redo log file. Assigned by the Oracle server and used by the DBA during archiving and recovery of log files.
The event during which LGWR stops writing to one online redo log group and starts writing to another.
One of five background processes used by an Oracle instance. Log Writer writes redo log entries to disk. Also called LGWR process.
A feature in which information about an individual connection is written to a log file. See also tracing.
Structure determined by one or more tablespaces, the database's schema objects (e.g., tables, views, indexes, clusters, sequences, stored procedures), and the logical storage structures, including tablespaces, segments, and extents. All these elements dictate how the physical space of a database is used. The schema objects and the relationships among them form the relational design of a database.
A statement about a relationship between two or more column values or constants, which may be true or false. Logical expressions are used in WHERE clauses in SQL statements and in search criteria in Form Builder.
A logical file comprises a character string used to refer to files or devices by a string other than their specific names. Also known as logical assignment or logical name.
The logical operators are AND, OR, and NOT. You use AND and OR to combine conditions for a query, and NOT to make a negative condition, such as NOT BETWEEN. See also condition.
A username and password to use the Oracle server. This account is usually separate from an operating system account.
A user-specified command line used to run an application that is connected to either a local or remote database. The logon string either explicitly includes a connect string or implicitly uses a default connect string.
A column whose datatype is defined as a LONG datatype. Each entry in a long column can be up to 1 Gb characters long. Users cannot apply SQL functions to LONG columns, nor use LONG columns in the CONDITIONS or to sort the data.
A standard Oracle datatype. A LONG column may contain any printable character, such as A, 3, &, or blanks, and can be any length from 1 to 2 Gb characters; alternatively it can be null.
A standard Oracle datatype similar to LONG, but which contains raw binary data. Values entered into LONG RAW columns must be in hexadecimal notation.
The default password for the SYSTEM user account at the time of its creation.
MAX_ESTIMATED_EXEC_TIME
You can specify the maximum estimated execution time by using this new resource plan directive. If this parameter is set, the Database Resource Manager estimates the execution time before the operation starts.
MAX_ROLLBACK_SEGMENTS
This parameter specifies the maximum size of the rollback segment cache in the SGA. The parameter value specified signifies the maximum number of rollback segments that can be kept online simultaneously by an instance
Recovery performed after media failure, such as disk failure. Hardware failure prevents the reading or writing of data and thus, operation of the database. Recovery steps vary depending on where the failure occurred. See also instance recovery.
A unit of memory equal to 1,048,576 bytes (1024 x 1024). It is often rounded to one million bytes.
There are several basic memory structures associated with Oracle: the System Global Area (which includes the database and redo log buffers, and the shared pool) and the program global area. Memory structures are used to fulfill several requirements. For example, memory is used to store program code being executed and to store data that is shared among database users.
Similar to the mirrored redo log feature; a number of identical control files may be maintained by Oracle, which updates all of them simultaneously. The loss of one control file, therefore, does not cause the database to halt, as long as other control files are available.
To associate a database with a started instance in order to perform maintenance on the database or to open it and make it accessible to database users.
A database associated with an Oracle instance. The database may be opened or closed. A database must be both mounted and opened to be accessed by users. A database that has been mounted but not opened can be accessed by DBAs for some maintenance purposes.
A database that has been started (mounted and opened) in Shared mode so that multiple instances can access it.
A mode of database operation that allows several users to access a database concurrently. Also called multiple user.
An operating system that can handle programs in parallel and is capable of performing background processing.
A user-accessible entity, uniquely identified by name, that contains data. Access to a named object implies the potential ability to read, write, or execute its contents. For example, a named object could be a table.
An Oracle server feature that enables users to access the database in their own language.
A table that has a column whose datatype is another table.
An Oracle product that works with the Oracle server and enables two or more computers that run the Oracle server to exchange data through a third-party network. Net8 supports distributed processing and distributed database capability. Net8 is an "open system" because it is independent of the communications protocol, and users can interface Net8 to many network environments.
A subdirectory of the Orant directory that contains message and configuration files for Net8 products.
A group of two or more computers linked through hardware and software to allow the sharing of data or peripherals.
Network file access and transfer software developed by Sun Microsystems, Inc.
Any industry standard transport protocol, such as TCP/IP or APPC.
A parameter that specifies the character string returned by the number format mask L, the local currency symbol, overriding that defined by the NLS_TERRITORY parameter.
A parameter that specifies the language for the spelling of the day and month names by the functions TO_CHAR and TO_DATE, overriding that specified by the NLS_LANGUAGE parameter.
A parameter that specifies the character string that is returned by the number format mask C, which is the ISO currency symbol. The NLS_ISO_CURRENCY parameter overrides the NLS_TERRITORY parameter.
A parameter that is specified for each operating system shell. It has three components: language, territory, and character set. The language component specifies the conventions of the language for Oracle messages, day names, and month names. The territory component specifies conventions such as default date format, and the decimal character used for numbers. The character set component specifies the character set used for client applications. All the components are optional.
A parameter that specifies the conventions for session characteristics, such as language for the server messages, language for day and month names, and default sorting sequence for character data.
A parameter that defines the decimal character and the group separator, overriding those specified by the NLS_TERRITORY parameter.
A parameter that specifies the type of sorting sequence for character data, overriding that specified by the NLS_LANGUAGE parameter.
A parameter that specifies the default date and numeric characteristics, such as date format, decimal character, and group separator.
The absence of a value for a given item. A null implies nothing more than "a value is not applicable" or "the value is unknown." Nulls are not equal to any other value, even to each other. Comparisons with nulls are always false.
A standard Oracle datatype. A NUMBER column can contain a number, with or without a decimal point and a sign.
A named structure in the Oracle database, such as a table, index, or form.
A group of data in a form that you can copy, move, or delete in a single operation.
The auditing of accesses to specific schema objects without regard to the user. Object auditing monitors the statements permitted by object privileges, such as SELECT or DELETE statements on a given table.
Privileges granted (assigned) to end-users so that they can use a database application to accomplish specific tasks. Object privileges perform a particular action on a specific object. For example, the privilege to delete rows of a specific table is an object privilege.
Oracle Call Interface(OCI)
When an application connects to a server
the database has to manage the physical connections by itself. OCI removes the
need for the servers to handle the physical connections by handling the
connections for the database.
A set of guidelines for organizing the operating system directory structure for installing Oracle products and for database operations.
An archived copy of a redo log file.
The archiving of database data while the database is running. The DBA does not need to shut down the database to archive data; a usable copy of the database can be made even while the database is being updated.
File that records changes made to the database. The redo entries are periodically written from the redo log buffers of the SGA to an online redo log file by the background process LGWR. An online redo log file can be individual or mirrored; in the latter case, it is an online redo log group, made up of online redo log members.
A database that has been mounted and opened by an instance and is available for access by users. See mounted database.
System components that implement standard nonproprietary interfaces, permitting communication with other systems implementing the same standards (interoperability).
The system software that manages a computer's resources, performing basic tasks, such as allocating memory and allowing computer components to communicate.
A clearly defined action that allows users to manipulate the data and structures of a database. The operations on a database must adhere to a predefined set of integrity rules.
The part of the Oracle kernel that determines the best access path to use to perform the operation requested by a SQL statement.
The top directory in the Oracle directory hierarchy on some directory-based operating systems.
On UNIX-based systems, an environment variable specifying the top Oracle directory.
The Oracle side of the program interface, which provides security between the user program and the Oracle program. See also user program interface.
The object-relational database management system (ORDBMS) developed by Oracle Corporation. Components of the ORDBMS include the kernel and various utilities for use by database administrators and database users.
A running Oracle database system. Components of the Oracle server include an Oracle instance and a database.
A unique name for an Oracle instance on a computer that may run multiple Oracle instances concurrently. To switch between Oracle databases, users must specify the desired SID.
A name, known to the Oracle server, by which some form of access to an Oracle database may be gained. An Oracle user will have a name and associated access rights to different tables and menu options.
A name resolution product for the Oracle servers and Net8 networks.
A subdirectory of the Orant directory that contains programs used for installing Oracle products.
A tablespace in which parts of the rows exceeding the specified threshold limit of an index-organized table (IOT) are stored.
A method of encapsulating and storing related procedures, functions, and other package constructs together as a unit in the database. While packages provide the database administrator or application developer with organizational benefits, they also offer increased functionality and database performance.
An interface to the package that declares all public constructs of a package.
The private constructs of a package that include the logic.
An Oracle instance running in parallel mode can share access to the database with other instances in the same Oracle parallel server.
Some hardware architectures (e.g., loosely coupled processors) allow multiple computers to share access to data, software, or peripheral devices. With systems that have the parallel server option, Oracle can take advantage of such hardware platforms by running multiple database instances that share a single physical database. In appropriate applications, the Oracle parallel server allows access to a single database by the users on multiple machines, increasing availability.
A value specified by a command. A parameter can be a file specification, a symbol value passed to a command procedure, or a word defined by the operating system.
In SQL*Plus, a substitution variable consisting of an ampersand followed by a numeral (&1, &2, and so forth).
A variable that is passed to or from a procedure or a function.
File that contains information to initialize an Oracle instance.
A file that defines the command line parameters for a load performed using SQL*Loader.
A phase of SQL statement processing in which a SQL statement is examined and validated to make sure it is properly formed (that it follows syntax rules) and that all necessary information is accessible, in order for the Oracle server to execute the statement. A parse error can occur because of incorrect syntax or naming of nonexistent database objects.
An operating system backup of a database that is less than a full backup. The backup of an individual tablespace's data files is an example of a partial backup. Partial backups are useful only when the database's redo log is operated in ARCHIVELOG mode. A variety of partial backups can be taken to accommodate any backup strategy.
A contiguous range of blocks on a physical disk.
A means of authenticating a user. A password is used for data security and known only to its owner. Passwords are entered in conjunction with an operating system login ID, Oracle username, or account name in order to connect to an operating system or software application (such as the Oracle database). Whereas the username or ID is public, the secret password ensures that only the owner of the username can use that name, or access that data.
An operating system file that is used to authenticate privileged users.
A parameter that controls utilization of a block in a table, or an index. For a table this value represents the proportion of block space that will be reserved for row growth resulting from updates. For an index, this is the amount of space that will be left free in each block during the creation of an index. In an index, this space can be used for inserting new entries.
A storage parameter associated with a schema object to specify the percent by which the size of the third and subsequent extent is increased over the size of the preceding extent.
A block utilization parameter that determines when a block, which has been filled up to 100-PCTFREE will again be available for inserts. See also PCTFREE.
A standard storage allocation on a disk. The native block size varies across operating systems. The logical Oracle block size may differ from the native operating system block size. See also block.
Determined by the operating system files that constitute the database. Each Oracle database is comprised of three types of files: one or more data files, two or more redo log files, and one or more control files. The files of a database provide the actual physical storage for database information.
The Oracle procedural language extension of SQL. PL/SQL combines the ease and flexibility of SQL with the procedural functionality of a structured programming language, such as IF, THEN, WHILE, and LOOP.
A subdirectory of the Orant directory that contains message files, SQL scripts, and demonstration files for PL/SQL.
A subdirectory of the Orant directory that contains message files and the SQL*Plus procedures of a database.
Acronym for process monitor. See process monitor (PMON).
In a database table, a set of columns used as the identifier for a row. The combination of column values is unique for each row in the table. The Oracle server ensures that the key values are NOT NULL.
A rollback segment whose name has been specified in the INIT.ORA file for a particular instance, and is thus, brought online by that instance. Contrast with public rollback segment.
A synonym defined by an Oracle user for a database object, so that the user can more conveniently refer to that object; contrast with public synonym.
A right to successfully execute a particular type of SQL statement. Some examples of privileges include rights to connect to the database (create a session), to create a table in your schema, to select rows from someone else's table, and to execute someone else's stored procedure. The privileges of a user in an Oracle database can be divided into two distinct categories: system privileges and object privileges.
The auditing of the use of system privileges without regard to specifically named objects. Privilege auditing can be broad and audit all users, or focused to audit only selected users.
A set of SQL and PL/SQL statements grouped together as an executable unit to perform a very specific task. Procedures and functions are nearly identical; the only difference between the two is that functions always return a single value to the caller, while procedures do not return a value to the caller.
A thread of control in an operating system; that is, a mechanism in an operating system that can execute a series of steps. Some operating systems use the terms job or task. A process normally has its own private memory area in which it runs. An Oracle database system has two general types of processes: user processes and Oracle processes.
A failure in a user process accessing Oracle, such as an abnormal disconnection or process termination. The failed user process cannot continue work, although Oracle and other user processes can. The Oracle background process PMON automatically detects the aborted user process (or is informed of it by Net8), and rolls back the uncommitted transaction of the user process (if one was in progress), releasing any resources that this process was using.
One of five background processes used by an Oracle instance. Process Monitor releases the locks and performs the cleanup when a process accessing a database terminates abnormally.
A file or set of information that is called or used at a particular time. A profile consists of a named set of resource limits and password usage rules. For example, all of the settings for various functions may be specified in a system profile, including the number of concurrent sessions the user can establish, the CPU processing time, the amount of logical I/O, the allowed amount of idle time for the user's session, and the allowed amount of connect time for the user's session. Different profiles can be created and assigned individually to each user of the database. A default profile is present for all users not explicitly assigned a profile. The resource limit feature prevents excessive consumption of global database system resources.
A memory buffer that contains data and control information for a server process. PGA is allocated when a server process is started. The information in a PGA depends on the configuration of Oracle. Contrast with System Global Area.
Visible or available to all users. Though by default all objects are private, many database objects can be made public. While only DBAs can create public synonyms or database links, any user may grant public access to his own objects.
A rollback segment that may be allocated to any instance accessing the database. Once allocated to an instance, a rollback segment cannot be allocated to other instances until the first instance is shut down. See rollback segment and contrast with private rollback segment.
A synonym for a database object created by a DBA to make access to that object more convenient for all database users. Contrast with private synonym.
A SQL SELECT statement that retrieves data, in any combination, expression, or order. Queries are read operations; they do not change any data, they only retrieve data. Queries are often considered to be DML statements.
The process of choosing the best access path to satisfy a query. The optimizer evaluates the query to see which indexes can be used, and chooses the best possible path to the data.
Quiescing
In this database state only DBA transactions and queries are allowed. n the quiesced database state, ongoing non-DBA transactions, queries, or PL/SQL statements are not allowed on the database. This means that the database instance runs in the restricted mode. Without a provision to quiesce the database, as an alternative you must shutdown and reopen the database in restricted mode.
A limit on the amount of database storage used by a database user. A DBA can set tablespace quotas for each Oracle username.
Searching an index for key values between specified values. A range scan normally relates to numeric or structured fields; for example, dates, ages.
A standard Oracle datatype, RAW is used for storing binary (noncharacter) data.
A subdirectory of the Orant directory that contains server files, scripts, libraries, and other README files required for a database.
A feature of all versions of the Oracle server that guarantees that the results of any query are a consistent set of data as of the time the query was executed. A read-consistent view of the data can be thought of as a "snapshot" of the data as of a point in time. See integrity (data).
A lock used by some databases (not Oracle) to allow shared read access to an object, thus preventing updates. The Oracle server does not use read locks. See also share lock.
The ability to run multiple queries within a single transaction, all of which are read-consistent with respect to the same point in time (i.e., queries in this transaction do not see the effects of intervening committed transactions). If you want to run a number of queries against multiple tables and if you are doing no updating, you may prefer a read-only transaction. After indicating that your transaction is read-only, you can execute as many queries as you like against any database table, knowing that the results of each query are consistent with respect to the same point in time.
Real Application Clusters (RAC)
In the Real Application Cluster environment, all the instances access a single parameter file and this file resides on a shared device. The RAC architecture introduces a new phase of Cache Fusion. In Cache Fusion one instance transfers the latest image block to another instance. This new feature reduces the overhead of resolving write-write conflicts caused by instance contention.
A synonym for row; one row of data in a database table, having values for one or more columns.
A unit of information in a particular panel, corresponding to a row in that panel.
A feature in which database users changing data need only lock the row being updated rather than the block or table containing the row, at the instant of update. Row-level locking supports higher concurrency than block-level or table locking.
A process in which the Oracle server brings the database and associated files back to a consistent state. Some types of recovery are automatic and some require DBA intervention. See also instance recovery and media recovery.
Calls made to the database that generate other calls on their behalf. A SQL statement that is required to execute another SQL statement.
A sequential log of all changes made to the data. The redo log file is written and used in the event that a failure occurs before changes are written to disk; it is used to reapply the changes to disk. The redo log consists of two or more redo log files. When the file currently being written fills, the other file is reused. See also online redo log and offline redo log.
A part of the SGA that stores redo entries, which are records of changes made to the database. The redo entries stored in the redo log buffers are written to an online redo log file. The size of the redo log buffer can only be altered by shutting down and restarting the instance.
A file containing records of changes to the databases. These files are used for recovery purposes. See also redo log.
A condition that guarantees that the values in one column also exist in another column of the same or a different table. This guarantee is enforced through the use of integrity constraints.
A validation rule that is used to define a foreign key and parent key relationship.
A computer program designed to store and retrieve shared data. In a relational system, data is stored in tables consisting of one or more rows, each containing the same set of columns. Oracle is a relational database management system. Other types of database systems are called hierarchical or network database systems.
A symbol used in search criteria to indicate a comparison between two values, such as the equal sign in "WHERE DEPTNO = 10." Rows in which the comparison results in "true" are returned in the result (fetched), while rows in which the comparison returns "false" are rejected from the result.
In the Oracle server, an association between two or more tables (implied by the data values).
The REMARK command is used to enter comments in the SQL script files.
A computer on a network other than the local computer.
A database on a computer other than the local database. A remote database is usually a computer on the same network, but at a different node (i.e., a database that you use through a database link).
REMOTE_LOGIN_PASSWORDFILE
The value that you specify for this parameter determines the mode that is used to connect to the database and also the users who can connect. This parameter takes "Shared", "None", and "Exclusive" as values. None is the deafult value.
A database feature in which you can execute repeated queries on one or more tables with the assurance that the data you see will not appear to change while you are using it. A desirable feature (such as for printing a set of related reports), but one that requires additional DBMS logic, if the database tables are to be concurrently accessed by numerous users or updaters. Repeatable reads are supported in at least two different ways (using LOCK TABLE or SET TRANSACTION READ ONLY).
A database feature in which identical and updateable copies of a table are stored in two or more databases. Table replicates are called synchronized copies.
A mechanism for storing any information to do with the definition of a system at any point in its life cycle. Repository services would typically be provided for extensibility, recovery, integrity, naming standards, and a wide variety of other management functions.
A logical database object or physical structure that may be required or locked by database users. Resources that users can directly lock are rows and tables; resources that the Oracle server can lock are more numerous and include data dictionary tables, caches, and files.
To use previously archived data in order to bring data up to date or to replace corrupted data with data known to be correct.
To reactivate data that has been stored in archives. See also recovery, instance recovery, and media recovery.
To copy, or fetch, selected rows from one or more tables.
A list of usernames that can be granted privileges.
Named groups of related privileges that are granted to users or other roles.
To discard some or all pending changes made to data in the current transaction, using the SQL statement ROLLBACK. You can roll back a portion of a transaction by rolling back to a savepoint.
As a part of recovery, to undo changes made to a database that were never committed by users.
To reapply changes made to data that were made but subsequently lost due to hardware failure. Data is rolled forward during media recovery and instance recovery. The redo log contains the redo entries used to roll forward; media recovery may also require offline redo logs.
The second half of the recovery procedures. After the roll forward, any changes that were not committed must be undone. After the redo log files have been applied, then the rollback segments are used to identify and undo transactions that were never committed, yet were recorded in the redo log. Oracle completes this step automatically.
A database object used to record before-images when a change is made. It is used to undo changes in the database in the event of transaction rollback (i.e. undoing all the changes done in a current transaction), crash, media recovery or, if necessary, for read consistency. Every instance requires at least one rollback segment.
ROLLBACK_SEGMENTS
This parameter allocates one or more rollback segments to the current instance. When you set this parameter, the instance acquires all of the rollback segments that you specify in this parameter, even when the number exceeds the minimum number required by the instance.
rollback segment undo(RBU)
The Oracle server uses rollback segments to store the undo information in the RBU mode. To start the instance in RBU mode you set the value of the UNDO_MANAGEMENT initialization parameter to MANUAL.
Synonym for record; one row of data in a database table, having values for one or more columns. Also called tuple.
One set of field values in the output of a query. See also column.
A feature in which database users changing data need only lock the row being updated rather than the block or table containing the row, at the instant of update. Row-level locking supports higher concurrency than block-level or table locking.
A feature in which database users changing data need only lock the row being updated rather than the block or table containing the row, at the instant of update. Row-level locking supports higher concurrency than block-level or table locking.
A portion of a row containing row header information and row data. Each database row is stored in one or more row pieces.
The portion of each row's required storage that precedes the data for a row and contains information about row pieces, chaining, columns in the row piece, and cluster keys.
A unique identifier that the Oracle server uses to obtain the physical address of the row. Considered a pseudocolumn. ROWIDs can be retrieved in a query using the reserved word ROWID.
A pseudocolumn generated by using the SQL keyword ROWNUM in a query. ROWNUM returns an integer for each row, starting with 1. The ROWNUM identifies the position of each row within the set of rows satisfying the query, before ordering.
A point at which work done thus far in a transaction is temporarily named using the SQL statement SAVEPOINT. Then the name can be used as an intermediate point for rolling back work. You may use multiple savepoints in one transaction at a time.
A user-defined limit on the number of decimal places to be stored for a column of datatype NUMBER. A scale is set when a table is created or changed using ALTER TABLE.
A collection of database objects owned by a particular user.
A collection of related objects. Schema objects are the logical structures that directly refer to the database's data. Schema objects include such structures as tables, views, sequences, stored procedures, synonyms, indexes, clusters, and database links. (There is no relationship between a tablespace and a schema: objects in the same schema can be in different tablespaces, and a tablespace can hold objects from different schemas.)
The level at, or range in which, a trigger operates. This domain is determined by the level (form, block, or item) at which you define the trigger.
An executable procedure written in SQL used to perform database administration. See also SQL script.
One or more criterion specified in WHERE clauses using expressions and conditions, to indicate the rows to be fetched by a particular query.
An index on a set of columns (optional or mandatory), which improves the performance of access to rows.
A set of properties, such as the actions (privileges and roles) available, the tablespace quotas (available disk space), and the system resource limits (e.g., CPU processing time) associated with a user.
The space used by a database object such as a table, index, and cluster. A segment consists of one or more extents.
The first block in the first extent of a segment, which contains segment overhead information, including an extent map for this segment.
To fetch rows from one or more database tables using a query (the SQL statement SELECT).
The list of items that follow the keyword SELECT in a query. These items may include column names, SQL functions, constants, pseudocolumns, calculations on columns, and aliases. The number of columns in the result of the query will match the number of items in the SELECT list.
A SQL statement that specifies which rows and columns to fetch from one or more tables or views. See also SQL statement.
A query in which one table is joined to itself by treating it as two tables, where one copy of the table is joined to the other copy in the join condition. Self-joins require the use of aliases, to give each copy of the table a temporary distinct name. See also join.
A database structure used to generate unique integers to be used as primary keys (which are guaranteed to be unique). Concurrent database users can use a sequence simultaneously. Sequences may be defined with many characteristics (for example, to ascend or descend, to have any increment or decrement, and to recycle values or not).
The provider of services requested by a client.
A process providing services to other cooperating processes.
Oracle software that handles the functions required for concurrent, shared data access to an Oracle database. The server portion receives and processes SQL and PL/SQL statements originating from client applications.
A process that processes database requests made by a user. For example, if a user queries some data that is not already in the database buffers of the SGA, the associated server process reads the required data blocks from the data files into the SGA. In a dedicated server configuration, a server process handles requests for a single user process. A multithreaded server configuration allows many user processes to share a small pool of server processes, thus minimizing the number of server processes and maximizing the utilization of available system resources. On some systems, the user and server processes are separate, while on others they are combined into a single process. If a system uses the multithreaded server, or if the user and server processes run on different machines, the user and server processes must be separate.
The name used by Net8 to identify an Oracle instance. The file TNSNAMES.ORA on client and server machines maps each service name to an instance running on one of the nodes in a network.
A session is a specific connection of a user to an Oracle server. The session commences when the user is validated by the Oracle server, and ends when the user logs out or when there is an abnormal termination.
A type of lock that allows other locks of the same type to coexist on the locked resource, so that more than one user may have access to that resource. Contrast with exclusive lock.
A shared storage area on the Oracle server that contains information required by server and background processes. Every instance starting a multiple-user database first allocates an SGA in main or virtual memory. The SGA supports communication between server and background processes, and tracks resources shared by users (such as cache buffers, database and log buffers, locks, and dictionary caches).
An Oracle instance running in shared mode (parallel mode) can share access to the database with other instances that are part of the same Oracle parallel server.
A portion of the SGA, created on instance startup, that contains shared memory constructs such as the shared SQL area and the dictionary cache. The shared pool caches the parsed versions of the most recently used statements and the most recently used data dictionary structures. This reduces the need to reparse a statement or load a dictionary structure from disk, improving performance.
SHOW PARAMETER is used in Oracle SQL*Plus Worksheet to display the current values for one or more initialization parameters.
The process of stopping a running instance in order to make a database unavailable, including closing and dismounting a database if one has been mounted and opened. Contrast with start up.
A privileged SQL*Plus command used to shut down an Oracle instance.
The default mode in which a database is mounted and opened, and where only one instance can access a database.
single sign-on
You can also use this feature to connect to the different Oracle services. By using this feature, users can access multiple accounts and applications with a single account.
Information stored in rollback segments to provide transaction recovery and read consistency. Rollback segment information can be used to recreate a snapshot of a row before an update.
A snapshot is a local copy of table data that originates from one or more remote master tables. A snapshot is periodically refreshed to reflect changes made to the master table.
Acronym for system monitor. See system monitor (SMON).
(verb) To rearrange a set of values into a new sequence, using rules of precedence, as in alphabetizing or putting in numeric order.
(noun) A program designed to perform a sort.
A program written in a language other than machine code that must be compiled or assembled to be used.
SPFILE
This parameters are stored in a disk file on the server. The SPFILE enables you
to make changes to the database that is persistent across shutdown and startup.
Sending or saving output to a disk storage area. Often used in order to print or transfer files.
Acronym for structured query language. See structured query language (SQL).
In SQL*Plus, the default buffer used to contain the SQL command or PL/SQL block most recently entered.
A complete command or statement written in the SQL language. In Form Builder, SQL statements can be invoked by triggers at various points in the processing of forms. Synonymous with statement (SQL).
A utility to load data from external files into Oracle tables.
A file containing SQL statements that you can run in SQL*Plus to perform database administration quickly and easily.
A complete command or statement written in SQL. In Form Builder, SQL statements can be invoked by triggers at various points in the processing of forms.
An interactive SQL-based language for data manipulation, data definition, and the definition of access rights for an Oracle database. Often used as an ad hoc reporting tool.
To start an instance, presumably with the intention of mounting and opening a database, in order to make a database system available for use.
The command issued to start an instance (presumably with the intention of mounting and opening a database), and thus make a database system available for use.
The auditing of a group of SQL statements without regard to specifically named objects. Statement auditing can be broad and audit all users of the system, or can be focused to audit only selected users of the system. For example, system auditing by user can audit connections to, and disconnections from, the database by the users SCOTT and LORI.
Occurs when there is a logical failure in the handling of a statement in an Oracle program (e.g., the statement is not a valid SQL construction). When statement failure occurs, the effects (if any) of the statement are automatically undone by the Oracle server and control is returned to the user or user program.
To undo or discard the effect of a single SQL statement. A statement-level rollback is automatically performed if an error occurs in the processing of a SQL statement. See roll back.
A set of PL/SQL constructs that are grouped together and stored in the database.
A set of procedures, functions, and packages of a database.
The internationally accepted standard for relational systems, covering not only query but also data definition, manipulation, security, and some aspects of referential integrity. See also data manipulation language (DML), data definition language (DDL), and data control language (DCL).
A directory that is contained within another directory.
A named PL/SQL construct. Functions and procedures constitute subprograms.
A query that is nested in a clause of a SQL command.
In SQL*Plus, a variable name or numeral preceded by one or two ampersands (&). Substitution variables are used in a command file to represent values to be provided when the command file is run.
SWITCH_TIME
You use this parameter to set the time for which the session executes before the session switches.
SWITCH_GROUP
This parameter depicts the group to which the current session switches.
An alias for a table, view, sequence, or program unit; a synonym is not actually an object itself, it is a direct reference to its base object. Synonyms are used to mask the real name and owner of an object, provide public access to an object, provide location transparency for tables, views, or program units of a remote database, and simplify the SQL statements for database users. A synonym can be public or private.
The orderly system by which commands, qualifiers, and parameters are combined to form valid command strings.
One of two standard DBA usernames automatically created with each database (the other is SYSTEM). The Oracle username SYS is created with the password CHANGE_ON_INSTALL. SYS owns the base data dictionary tables and views.
A named, defined, and interacting collection of real-world facts, procedures, and processes, along with the organized deployment of people, machines, various mechanisms, and other resources that carry out those procedures and processes.
A person responsible for the operation and maintenance of the operating system of a computer.
A logical time stamp the Oracle server uses to order events within a single instance and across all instances.
A shared storage area required by the Oracle server that contains information required by server and background processes. Every instance starting a multiple-user database first allocates an SGA in main or virtual memory. The SGA supports communication between server and background processes and tracks resources shared by users (such as cache buffers, database and log buffers, locks, and dictionary caches). May also be called the Shared Global Area.
system-managed undo(SMU)
In this mode of startup, the tablespace specified in the UNDO_TABLESPACE parameter is used to manage the undo. You must create the tablespace before you set the value of the parameter because if the specified tablespace does not exist, the startup fails. You start the instance in the SMU mode by setting the value of UNDO_MANAGEMENT parameter to AUTO.
A background process that performs instance recovery at instance startup. In a multiple instance system (one that uses the parallel server), the SMON of one instance can also perform instance recovery for other instances that have failed. SMON also cleans up temporary segments that are no longer in use and recovers dead transactions skipped during crash and instance recovery because of file-read or offline errors. These transactions are eventually recovered by SMON when the tablespace or file is brought back online. SMON also coalesces free extents within the database to make free space contiguous and easier to allocate.
The mechanisms that control the access and use of the database at the system level. System security includes valid username and password combinations, user authorization, the amount of disk space available, resource limits, and which system operations a user can perform.
One of two standard DBA usernames automatically created with each database (the other is SYS). The Oracle user SYSTEM is created with the password MANAGER. The SYSTEM username is the preferred username for DBAs to use when performing database maintenance.
A variable that indicates status or environment, which is given a default value by Oracle or SQL*Plus. Examples are LINESIZE and PAGESIZE. Use the SQL*Plus commands SHOW and SET to see and alter system variables.
The basic unit of storage in a relational database management system. A table represents entities and relationships, and consists of one or more units of information (rows), each of which contains the same kinds of values (columns). Each column is given a column name, a datatype (such as CHAR, DATE, or NUMBER), and a width (the width may be predetermined by the datatype, as in DATE). Once a table is created, valid rows of data can be inserted into it. Table information can then be queried, deleted, or updated. To enforce defined business rules on a table's data, integrity constraints and triggers can also be defined for a table. In Form Builder, a block in a form is associated with one base table. See also base tables, synonym.
A temporary substitute name for a table, defined in a query and only good during that query. If used, an alias is set in the FROM clause of a SELECT statement and may appear in the SELECT list. See also alias.
An integrity constraint that involves multiple columns of the same table.
A lock that reserves an entire table for reads or writes. A table lock is obtained using the SQL statement LOCK TABLE.
A logical portion of an Oracle database used to allocate storage for table and index data. Each tablespace corresponds to one or more physical database files. Every Oracle database has a tablespace called SYSTEM and may have additional tablespaces. A tablespace is used to group related logical structures together. For example, tablespaces commonly group all of an application's objects to simplify certain administrative operations.
A mechanism that limits the collective amount of disk space available to the objects owned by a user. Quotas (space limits) can be set for each tablespace available to a user. The tablespace quota security feature permits selective control over the amount of disk space that can be consumed by the objects of specific users.
Synonym for an operating system process.
A segment used by the Oracle server for a temporary work area during processing (typically sorting). Temporary segments are implicitly used by the Oracle server on behalf of users when needed. Many temporary segments can exist at any given moment.
When a user executes a SQL statement that requires the creation of temporary segments (e.g., the creation of an index), the user's temporary tablespace is used to store intermediate values. By directing all users' temporary segments to a separate tablespace, the temporary tablespace feature can reduce I/O contention among temporary segments and other types of segments. It also minimizes fragmentation of data files used for user objects.
A unique date and time denoting a particular event, such as the saving of a file. Timestamps are used for identification purposes, especially to locate the most recent version of a file, data item, or program. In Oracle auditing, timestamps can be stored to record the time when the auditing event occurred.
A trace file is created when a problem or exceptional condition is encountered while using a software program. The trace file contains information useful in diagnosing or locating the problem.
A facility that writes detailed information about an operation to an output file. The trace facility produces a detailed sequence of statements that describe the events of an operation as they are executed. Administrators use the trace facility for diagnosing an abnormal condition; it is not normally enabled.
A logical unit of work that comprises one or more SQL statements executed by a single user. According to the ANSI/ISO SQL standard, with which Oracle is compatible, a transaction begins with the user's first executable SQL statement. A transaction ends when it is explicitly committed or rolled back by the user.
TRANSACTIONS
This parameter specifies the maximum number of concurrent transactions. The greater values of this parameter increases the size of the SGA and can increase the number of rollback segments that are allocated.
A unique ID for every transaction that is created, used, and maintained by the Oracle server.
A lock appearing in Enterprise Manager that indicates that a transaction is holding row locks.
TRANSACTIONS_PER_ROLLBACK_SEGMENT
You specify the number of concurrent transactions that each rollback segment can handle by using this parameter. You can determine the minimum number of rollback segments acquired at startup by dividing TRANSACTIONS by the value of this parameter.
A PL/SQL procedure that is stored in the database and fired (implicitly executed) when an INSERT, UPDATE, or DELETE statement is issued against the associated table. Database triggers can be used to customize a database management system with such features as value-based auditing and the enforcement of complex security checks and integrity rules. For example, a database trigger might be created to allow a table to be modified only during normal business hours.
A DDL operation that deletes all rows in a table and optionally deallocates part of the storage used for a table and associated indexes.
A method used by a distributed DBMS to ensure that every local database participating in a single multinode, transaction commits or rolls back, in order to ensure data integrity across all nodes. Each commit actually involves two phases: preparation and verification for the commit and the actual commit.
UNDO_MANAGEMENT
You set this parameter to Manual or Auto to specify the Undo mode. When the value is set to Manual the instance starts up in the RBU mode and if the value if Auto, the instance will be in the SMU mode.
UNDO_TABLESPACE
This dynamic parameter to specify that the undo tablespace must be used in the SMU mode.
UNDO_RETENTION
This parameter contains the retention time of undo. The default value of this parameter is five minutes.
UNDO_SUPPRESS_ERROR
When RBU commands are used in SMU mode, this parameter helps suppress or display error messages that are raised.
Any combination of attributes and/or relationships that serves to uniquely identify an occurrence of an entity; or, any combination of columns that serves to uniquely identify an occurrence of a row in a table. Primary keys and unique constraints are alternative ways of implementing unique identifiers on a relational database management system.
One or more columns that are unique in each row of a table. A unique key can be used as a primary key.
A property of having no duplicates. If an index has been created for a table using the keyword UNIQUE, then every row in that table is guaranteed to be unique. In Form Builder, uniqueness is a property of a block; no commit operation in a block may succeed if it would result in two rows of the associated table having the same value for the key field.
Extents that are currently allocated to a segment, and thus are not available for use by other objects. A used extent may or may not contain data and is not released by the DELETE command. Contrast with free extents.
USE_ESTIMATE
You can specify whether the Oracle server needs to estimate the time by setting
this parameter value. The server uses this value to decide whether to switch a
session before an operation starts running.
Any person or group of people with some rights to access a computer facility. The same person may be known to a sophisticated system in several ways; for example, as an Oracle User, a user of an operating system, or a user of an electronic mail system.
Processes created and maintained to execute the software code of an application program (such as a Pro*C program) or an Oracle tool (such as SQL*Plus). The user process also manages the communication with the server processes. User processes communicate with the server processes through the program interface. See also user program interface.
The part of the user process that is responsible for translating user requests into calls to the server process.
A command line argument used by utilities such as Export and Import that allows you to specify your Oracle username and password with an optional Net8 address.
It specifies the location where the user TRACE files are created.
The name by which a user is known to the Oracle server and to other users. Every username is associated with a private password, and both must be entered to connect to an Oracle database. See also account.
A trigger that is fired when an UPDATE operation is done on a table.
An SQL statement that is used to update an object, such as a table.
A category of the data dictionary view that provides information about the objects owned by that user.
An object that is compiled and can be used when referenced.
Equivalent to the CHAR datatype, a standard Oracle datatype used to store character (alphanumeric) data. CHAR data is fixed-length and VARCHAR is variable-length.
A named object that can be assigned a value and whose assigned value may change over time. SQL*Plus uses substitution, system, and user variables.
V$DB_CACHE_ADVICE
This view is used to collect and display the buffer cache advisory information. This dynamic view contains the buffer cache statistics that are gathered. This view contains different rows that predict the estimated number of physical reads for different cache sizes.
V$ROLLNAME lists the names of all online rollback segments. It can only be accessed when the database is open.
V$ROLLSTAT contains rollback segment statistics.
V$SESSION stores the session information for each current session view.
V$SORT_SEGMENT contains information about every sort segment in a given instance. The view is only updated when the tablespace is of the TEMPORARY type.
V$SORT_USAGE describes sort usage.
V$SPPARAMETER
You can query the V$SPPARAMETER view to see the contents of the SPFILE. The V$SPPARAMETER view returns NULL when you use the PFILE for instance startup.
V$TRANSACTION lists the active transactions in the system.
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