Clipper is a database development tool based on the dBase III Plus file structure. All code developed with
Clipper can be linked and compiled into machine-executed code that can be run directly from the DOSprompt.
Clipper allows many enhancements to the database parameters of dBase III Plus and dBase IV and offers the ability to create user-defined functions, link object files compiled with other languages (such as C and assembler) and data arrays, and call external programs. No runtime module is required. Clipper contains a library, an error handler, a debugger, and a compiler. The library stores frequently used routines. The error handler system lets a programmer control the response of an application when and where errors occur. The debugger assists in finding and correcting both logical and execution errors.
The compiler translates the source code into an executable format. Once the source code is debugged and compiled, the program (stored in an executable file) will run faster than non-compiled dBase III Plus programs. This executable file can be transported to any machine. You do not need Clipper or a runtime version to run the compiled program. Clipper makes it easy to create multi-user applications that support record and file locking and can open files for shared or exclusive access. It supports single and multi-user commands with no need to purchase additional runtime licences or multi-user versions. Research Clipper
Ashton-Tate's dBase III Plus became an industry standard relational database management system The product line, beginning with dBase II (formerly known as Vulcan), which was the first database manager for the personal computer, was built around a powerful, flexible programming language. Many third party vendors have chosen to support the dBase standard and there are a variety of add-on and work-alike products available. dBase III Plus includes The Assistant, a menu-driven program with some relational capabilities that leads you through the maze of dBase procedures using pull-down menus and context-sensitive help. The commands in The Assistant appear on the screen. The Applications Generator is a menu-driven dBase module that brings you through the process of creating a custom program and shows how to design screens, menus, and reports.
dBase III Plus includes a 'Data Catalog' to keep track of related files. When you enter '?' you get a list of all files currently available. The menu-driven query facility lets you define and save a filter criteria. Research dBase III Plus
Ashton-Tate's dBase IV was a greatly enhanced version of dBase III Plus and provided more facilities for the power user to develop turnkey applications without the need to write code. The Control Center was an extension of The Assistant in dBase III Plus and was much more powerful. The Control Center let users open and close files, create views and reports, and run programs that provide the novice end-user with easier access to dBase files. Reports, forms, and queries produced through the Control Center generate dBase source code which can be edited. The Query By Example panel of the Control Center displays a visual representation of the data file. By specifying criteria within a view, you can select records, display fields, or combine data from several database files. Without leaving dBase IV, you can run DOS operations such as CHKDSK or DIR through the DOS window. dBase IV can save 47 indexes to a single file. Index files are automatically created with every database file. Each time you open a database file, the associated index file is automatically opened. This is much easier than opening data and index files separately as required in dBase III Plus. The new Application Generator writes all code necessary for incorporating forms, reports, and files into a turnkey application. The dBase/SQL command programming language lets you create, modify, or query databases using SQL commands. You can issue SQL commands from the dot prompt and include SQL procedures within dBase programs. This allows access to dBase files by mainframe and minicomputer users who are familiar with SQL. When dBase IV executes SQL commands, it first translates the code from SQL to actual dBase source code. This translation prevents users from accessing external SQL code. Enhancements to the programming language let you create two dimensional arrays, multi-child relationships, and data validation support. A transaction processing procedure creates a transaction log file of changes made to se files. This helps avoid data loss due to power shortages, inadvertent reboots, and system failures.
When used with Ashton-Tate's Chart-Master, the dBase/ Chart-Master Bridge let users graph data files. The report and form generator are WYSIWYG, so it is easier to develop forms and reports. The screen painter displays memo fields through a window, and a pseudo compiler increases the speed of all commands issued at the dot prompt up to ten times faster than in dBase III Plus. Memo fields can be searched, copied to and from, and are available for program control. This lets you program
dBase IV to perform automatic queries on memo fields. Built-in printer drivers support bold, italics, underlining, superscript, and subscript printing. Research dBase IV
Foxbase+ is a developmental tool based on the dBase data structure and programming language. Foxbase+ creates files with a .FOXextension which must be run with either Foxbase+ Development or Foxbase+ Runtime. A runtime version is necessary to distribute programs to other users. Under the runtime version, Foxbase+ programs may be executed but not modified. The runtime version ensures the integrity of source code by only allowing users with the development program access to the source code.
Foxbase+ includes an interpreter similar to dBase from which you can run
Foxbase+ programs or any uncompiled dBase III Plus program. In fact, you can run almost any dBase III Plus command from the Foxbase+ dot prompt without worrying about incompatibility. The Product's Assistant is similar to that in dBase III Plus. Foxbase+ has many features that make it easy to use, such as the FoxCentral interface, which allows novice users to take advantage of Foxbase+'s features. A screen and code generator is also included. Research Foxbase+
FoxPro is the PC version of FoxBASE+/Mac. It is a relational database with a report generator, application generator, and screen painter. Although it is a character-based product, it has some features of a graphical interface: pull-down and pop-up menus, buttons, check boxes, and scroll bars. FoxPro can be used for simple data entry, query and report applications, or complex menu- driven user applications. For less experienced users, it offers an easy-to-use, mouse-driven interface; for developers, it offers an interactive syntactical mode. There are step-by-step tutorials geared to four levels of experience. Most functions run in their own window. Colours can be assigned to any screen area. Applications created in Foxbase+ and dBase III Plus are fully supported. Research FoxPro
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Clipper
