Paradox (database)

Paradox is a database development environment or a file-based database format created by Borland and Corel, which dBASE III, dBASE IV, dBASE 3 and is available on the market very similar and since the 1980s.

Construction

Database

Paradox is designed for use with the Borland Database Engine ( BDE). This is not itself part of paradox, but a standalone library and is used in many other software products.

The BDE provides access to a relational database available as a database interface. In the case of Paradox as a database format there is any table (*. DB) and each index a ( primary index *. PX ) or two (per secondary index each *. XG? , And *. YG? ) Own file (s). If a table contains memo fields, validity checks, or formatting information (TV *. MB, *. VAL, *. ) These are also stored in special files. In multi- user operation, these files are located on a network drive, coordinate while the BDE instances of participating computers to share access to each other by a network control file (" PDOXUSRS.NET " ) and lock files (*. LCK ). Paradox or the DB engine dominated so-called " record locking " ( locking individual records) and is therefore - in contrast to competitors such as Microsoft Access - better suited for multi-user operation.

User interface

Core functionality of Paradox are the forms. These are Windows window that you design with the help of the ( paid ) developer version by placing pre - entry and controls. This produces screens for viewing and entering data.

Programming for the purposes of program lines of code is not required. Loading, Blocking and storing records concerned the paradox runtime environment automatically.

Another user interface are the so-called reports. They are similarly constructed as the forms are but the screen does not display, but for formatted printing.

A form will show each file, as well as a report.

Script language

For almost all events (such as inputs, leaves or clicks ) can be stored program code that changes the Paradox own processing of the event in any way. For example, you can at the event "Save" detect inconsistent data, display a message and cancel the registration. In modern terms, you can call this script language.

In Paradox is available as a scripting language the Paradox Application Language ( PAL) or ObjectPAL ( in the Windows versions ) are available. ObjectPAL is the object-based variant of PAL ( it is here between object-based and object-oriented correctly when Paradox distinction ). Both of which are derived from Pascal.

Often the script language is blurred also called " Paradox".

Application programming

Paradox applications are compiled into an intermediate code. The end of these programs continue to be a Paradox system or a ( free ) Paradox Runtime is required. Unlike some Access must be by the Teilkompilierung the source code will not be passed.

Revision history

Paradox for Windows 1.0 was released in early 1993 marketing reasons, the version 1.1 was launched in 1994 as version 4.5 to the market -. Because Paradox for DOS in this version stand was. The Paradox table format is therefore supported in Paradox for Windows 1.0 and 4.5, also up to Level 4. Paradox for Windows 5.0 was then the actual second generation (Paradox Table Level 5). Then paradox came in a version for Windows 7 16- bit and Windows 32- bit ( "Table Level 7" - the last stand format ). The product was made by Paradox Version 7 for Windows Corel (first version of Corel Corel Paradox 8). Corel integrated the program into the Professional versions of its WordPerfect Office Suite. It was released in versions 9, 10, 11, 12, X3 and X4 of the Office suite. The last published by Corel Paradox version 11.0.0.663, which was delivered in X4 Service Pack 1. The last German version is Paradox 9

Security

The content of unencrypted Paradox tables with paradoxfremden means, even simple word processing programs to read. The Paradox program provides the ability to encrypt tables so that when accessed by Paradox password is needed. To decrypt such tables but you do not necessarily need the password: The rules of encryption are fixed and the key to reading is stored in the database, so no brute-force password search is necessary. Various tools such as decryptpdxtable, pxunsec (up to version 4) and pxdazz (up to version 7) can be used to store an unencrypted copy or to determine the password of a Paradoxtabelle. Furthermore, there are some universal passwords, with each encrypted Paradoxtabelle can be opened.