Borland Paradox

Paradox is a relational database management system originally published by Ansa Software and later by Borland and Corel. It was popular in the DOS and Windows database market.

What You Can Upload

• .DB table files
• .MB memo/BLOB files
• ZIP archive with complete file sets

What You Get Out

DataMeans converts your data into multiple modern formats:

How to Export / Obtain Files

1. Locate your Paradox application's data directory
2. Copy all .DB table files
3. Include associated .MB memo files
4. Create a ZIP with all files
5. Upload the ZIP to DataMeans

Supported Features

• Paradox 3.0 through 11
• Text read in the code page each table declares (437, 850, 1252 and others)
• Memo field support (.MB files, whatever the case of their names)
• Formatted memos delivered as their text
• Binary, OLE, graphic and Bytes fields delivered as their bytes, base64-encoded
• A keyed table's key becomes its primary key in the SQL files, wherever the data satisfies it
• Relationships between tables are suggested from the data; the ones you confirm on the job page become foreign keys in the SQL files

Known Limitations

• Password-protected tables are not supported: remove the password in Paradox first
• Validity checks (.VAL) and secondary indexes are not carried over
• A formatted memo's fonts and styles are not carried over, only its text

Note on the Excel formats. An .xlsx sheet holds at most 1,048,575 rows of data and 16,384 columns, and a legacy .xls sheet 65,535 rows and 256 columns. Rather than ship a file that looks complete but is silently cut short, DataMeans leaves a table out of any Excel format it does not fit and notes it in the job report. The .xlsx copy is also left out for tables of more than 8,000,000 cells (1,048,575 rows of 12 columns is 12.6 million), which take too long and too much memory to write, and the .xls copy for tables of more than 150,000 cells, which the legacy format takes far too long to write. The CSV, JSON and SQL outputs always contain every row.

Overview

Borland Paradox was a popular relational database management system for DOS and Windows, known for its intuitive Query By Example (QBE) interface and powerful reporting capabilities. It used a proprietary file format with separate files for data, indexes, and memos. Paradox was widely used in business applications during the 1980s and 1990s, particularly in the DOS era; Borland sold the product to Corel in 1996, and the final major version shipped in 2003.

History and Background

• 1985: Ansa Software releases Paradox 1.0 for DOS, introducing the QBE interface.
• 1986: Paradox 2.0 adds multi-user support with automatic table and record locking on PC networks.
• 1987: Borland acquires Ansa Software in a stock swap worth $29 million.
• 1989: Paradox 3.0 for DOS released, bundling the PAL-based Personal Programmer.
• 1990: Paradox 3.5 released; the separate Paradox SQL Link product adds connectivity to SQL database servers.
• 1992: Paradox 4.0 for DOS, rewritten with the Borland C++ windowing toolkit, adds memo and binary BLOB fields.
• 1993: Paradox for Windows 1.0 ships in January, introducing the ObjectPAL programming language; Paradox for Windows 4.5 follows the same year.
• 1994: Paradox 5.0 for Windows released, adding long integer, time, timestamp, logical, autoincrement, and BCD field types.
• 1995: Borland releases Paradox 7, a 32-bit version for Windows 95 and Windows NT.
• 1996: Borland sells Paradox to Corel in October.
• 1997: Corel Paradox 8 released as part of Corel WordPerfect Suite 8.
• 2003: Paradox 11, the final major version, ships with WordPerfect Office 11 Professional.
• 2009: Paradox receives its last update, a hot fix issued with WordPerfect Office X4.

File Format Specifications

Primary Files:

• .db: Data table file with fixed-length records
• .px: Primary key index file
• .mb: Memo/BLOB storage for memo, binary, graphic, and OLE fields
• .val: Field validity checks and referential integrity definitions
• .tv: Table view settings

Index Files:

• .Xnn/.Ynn: Paired single-field secondary index files (nn = field number)
• .XGn/.YGn: Paired secondary index files for composite and case-insensitive indexes, numbered sequentially from 0
• Descending secondary indexes were added with format level 7

File Structure:

• Header block with table metadata (record size, record count, block size, file version)
• Fixed-length records stored in data blocks
• Primary index blocks organized as a multi-level tree for fast lookups
• Memo and BLOB values stored in the .mb file, referenced by 10-byte pointers in the record
• Block size: 1024-4096 bytes, selected per table (header code 1-4 multiplied by 1 KB)

Data Types and Structures

Database Structure:

• Tables as primary data containers
• Referential integrity and validity checks stored in .val files
• Optional password protection with table encryption
• Multi-user concurrency through table and record locking
• Saved queries and reports stored in separate files alongside tables

Version Differences

Compatibility Notes:

• Later versions read tables created at earlier format levels
• The Borland Database Engine (BDE) can create tables at level 3, 4, 5, or 7
• Field types introduced at level 5 require a level 5 or level 7 table
• Tables can be password-protected and encrypted
• Open-source libraries such as pxlib read all table versions from 3.0 onward

Technical References

• Wikipedia: Paradox (database)
• Paradox Table File Format Specifications (Randy Beck)
• pxlib: Library to Read and Write Paradox Databases
• DOS Days: Borland Paradox
• Corel Paradox (WordPerfect)