3.1. - Generalities
3.2. - The MENU working mode
3.2.1. - Data manipulation
3.2.2. - The use of another working modes
3.2.3. - Auxiliary tools
3.3. - The COMMAND working mode
3.4. - The PROGRAM working mode
3.5. - The GENERATOR working mode
3.6. - Files types
We will present a DBMS User Interface by using the example of one commercial product family, and namely the X-BASE DBMS family. We do this because we will use at the course and at the laboratory works the FOXPRO package to exemplify the basic concepts of DBMS software products.
The FOXPRO package integrates the management of the Relational Data Structures (RDS) in a very powerful Programming Environment (PE). This PE is built in a SYSTEM SCREEN that offer the following facilities:
- To assure two data processing modes:
* An INTERACTIVE access mode (STEP by STEP COMMAND run) by providing the direct access to the COMMAND language
* The streaming of the simples COMMANDS into PROGRAMS that can be run in an OFF LINE processing mode
- To execute the COMMANDS, through the SYSTEM MENU options, for manipulating the data structures without knowing the COMMAND language
- To provide a powerful set of tools for maintenance the data structures and the also procedure structures (text editing, files maintenance, tracing and debugging running procedures, context sensitive help functions, manipulating windows ans.); this tools are accessible also through the SYSTEM MENU
- To provide three kinds of procedures running:
* INTERPRETATIVE mode - running the COMMANDS directly from the source text (STEP by STEP in DEBUGING mode or IN STREAM in running mode)
* EXECUTIVE mode - running the compiled COMMANDS (STATEMENTS) from an OBJECT CODE
* INDEPENDENT mode - running a COMPILED and LINKED OBJECT CODE that is understood directly from the Operating System
The PE offers four WORKING MODES:
- MENU working mode
- COMMAND working mode
- PROGRAM working mode
- GENERATOR working mode
In this Working Mode the user has access to the System Menu (MAIN MENU). This MAIN MENU can be called from the COMMAND WINDOW with the command:
SET DEFAult TO SYSMenu
The menu system is built as a set of OPTIONS that may be chosen from the user within a HORIZONTAL MENU (HM). It contains a horizontal bar viewed as a set of PAD-s that builds the HORIZONTAL OPTIONS. To each PAD it is associated a VERTICAL MENU (VM) built as a set of vertical BARS that are the VERTICAL OPTIONS. To each vertical bar it is associated either an action, which is expressed in a form of a command or a procedure name, or another VERTICAL MENU. In this latter case the vertical menu is named a HIERARCHICAL MENU.
The options in the WM or HM can be in two states:
- ACTIVATED state - marked by a highlighted bar
- DEACTIVATED state - marked by a normallighted (lowlights) bar
This facility allows to build context sensitive menus, that means the opportunities to activate or deactivate the options which follow in a given user menu, and so to guide the user in the selection of the permitted options in a given context.
In this Working Mode the user can get the following activities:
- Data structures manipulation
- The use the another working modes
- The Use the Auxiliary Tools
The user can:
- Define Data structures
- Load by appending (inserting) data values in the defined Data structures
- Update the data values in the Data Base Files
- Delete data values from the Data Base Files
- Retrieve the stored data for displaying, listing and editing (Browse Data)
3.2.2. - The use the another working modes
The COMMAND working mode is running in the COMMAND WINDOW (CW). To open this window we must use the following MENU options:
MENU / WINDOW / COMMAND
or briefly type : < CTRL > + < F2 > . We must push simultaneous two keys.
The CW is a TEXT editing window. The presence of the cursor in this window, checked with the blinking of the cursor, in this window, indicates that we can use the TEXT EDITOR for writing the commands text.
The CW has two functions:
- To permit in foreground the commands text editing, for further interpretation
- To permit in background the display of the invoked commands by the menus options
We can combine the two functions in the following manner:
- Select an option from the SYSTEM MENU
- Look at the interpreted command in the CW
- Update this command by adding, deleted or modifying some clauses
- Run (interpret) once more the updated command
The PROGRAM working mode can be invoked by selecting the program RUN option from the MAIN MENU. This menu also provides the possibility to prepare the object code for running programs. In this way the user can:
- EDIT the source codes (a sequence of commands named also statements) by calling the TEXT EDITOR in a program file window
- COMPILE the source text by calling the compiler that generate an object code and the possible compile errors
- RUN the object code by calling the EXECUTIVE module of the programming environment
The GENERATOR working mode can be invoked by selecting, from the MAIN MENU, the options that permits to build an APPLICATION or only the specific applications modules like SCREENS, REPORTS, RQBE-s or USER MENUS.
When we invoke one of the above-mentioned functions and no file is opened, the system automatically asks for an appropriate file.
3.2.3. - Auxiliary tools
3.2.3.1. - The work with WINDOWS
There are two kinds of windows:
- System windows
- User windows
A lot of system menu options allow us to manage in the same manner these two kinds of windows. The following actions are available:
- Activate the window
- Display and activate the objects in a window
- Deactivate the window
- Deactivate specific window and remove it from the screen
- Place the window on the screen - move a window to a different location on the screen
- Size the window - change the current size of the window
- Walking from one window to another - deactivates the current activated window and activates the next one
There are many other actions for working with windows. Using commands and functions from the programming language we can also do these actions. The system menu offers only the main actions for this purpose.
3.2.3.2. -The TEXT EDITOR
The programming environment offers an own TEXT EDITOR (TE) which can be used in all the TEXT WINDOWS. It disposes of a special memory buffer, named CLIPBOARD, in which the users can store some fragments of text for latter use. With this facility the users can transfer text from one window to another (for example he can copy text from a program file to the command window and vice versa) .The main facilities of a TEXT EDITOR are offered.
3.2.3.2. - The file management function
With this function we can copy, move and rename files. The FOXPRO versions that run in windows environment this function is substituted with the WINDOW FILE MANAGER function (the FILE MANAGER). The FILE option in the horizontal main menu doesn't belong to the FILE MANAGEMENT function. This option assure the possibility to create or update a file which a data or a procedure structures (Database files, Index files, Program files, Screen files, Report files ans.).
3.2.3.3. - The control of the outputs to printer
This facility permits to setup printer options like: select the printer type, the printer driver, the paper size, the print quality, and the output format orientation ans.
3.2.3.3. - The DEBUGGING function
This function consists of the facilities that are offered by two windows: the TRACE and the DEBUG windows, in which the programmer can look at the programs internal variables values, and also can run theirs procedures STEP by STEP or stopped them at selected breakpoints.
3.2.3.3. - The HELP function
The HELP function is a very important function that must be used a quickly answer to the programmer questions and the compilation and runtime errors. FOXPRO provides HELP based on what you are doing. That means it offers a context sensitive HELP, related to the current DIALOG, menu option or system windows. FoxPro even provides a handy list of related help topics that can be obtained by clicking on SEE ALSO option of the HELP window.
The COMMAND-working mode (CWM) is always used in the CW. The CW can be activated in all the moments of the work with the System Menu. It can also be activated at all breakpoints that occur in a program runtime. This provides the opportunity to combine the use of the three working modes: MENU, COMMAND and PROGRAM working mode. The commands edited in CW can be run by pushing the ENTER key. The Command Language has the following main restrictions:
- Each command must be filled on a line
- A line can be continued with a semicolon sign (;)
- The maximum size of a line is 256 characters
The command line are stored in a COMMAND STORAGE and can therefore be recalled and redo from this storage. Because the Control Structure commands needs more that one line they can not be run from the CW in a CWM, but only in PROGRAM working mode.
3.4. - The PROGRAM working mode
The PROGRAM working mode (PWM) consists of the running of the sequence of commands that are grouped in a program by editing and after they're compiled. The editing and the compiling a program can be made. by activating the TEXT EDITOR and the COMPILER from the MAIN MENU (see the section 2.2.2.) the user can build his appropriate menus and screens to communicate with the PROGRAM working mode.
The GENERATOR working mode (GWM) provides many powerful tools for develop and maintenance the programs and applications. A project and with him an application can be constructed with a lot of several kind of procedures modules like MENUS, SCREENS, REPORTS, RQBE-s a.s.o. .
All the needed information that describes DATA or PROCEDURES is stored in files that are differentiated by the file extensions. The main files type are presented in the following list:
- DBF - Database files - describe the data structure and store the data values
- FPT - Memo files - store the data values from the data fields of memo type
- IDX - Individual INDEX files - store the INDEX TABLE associated to the DBF-s
- CDX - Compact INDEX files - store the INDEX TABLES associated to the DBF-s
- VUE - View files - store the working environment associated to one or more procedures
- PRG - PROGRAM source files
- FXP - PROGRAM compiled code files
- EXE - PROGRAM object code files
- PJX - PROJECT files - describe the content in modules of a project
- APP - APPLICATION object code files
- SCX - SCREEN files - the screen description information
- SPR - SCREEN generated files - the generated code from a screen description
- SPX - SCREEN compiled files - the compiled code from a screen generated code
- MNX - MENU files - the menu description information
- MPR - MENU generated files - the generated code from a menu description
- MPX - MENU compiled files - the compiled code from a menu generated code
- FRX - REPORT files - the report description information
- ERR - ERROR files - the compilation errors
- MEM - MEMORY files - the saved internal memory variables
- CFG - CONFIGURATION file - the values of the SET variables
- TMP - TEMPORARY files - any file that is only temporary saved
- TXT - general TEXT files
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