Multi-Value Databases

What are Multi-Value databases?

They are flexible, efficient, relational databases that are optimised for real-world data storage and queries. They differ from SQL databases in that:

• they offer a complete development environment rather than "just" a database. This includes:
  • the database system
  • a query language
  • a programming language
  • a job control language
  • one or more editors
  • interfaces to external environments
• within the database:
  • the data is not necessarily normalised and can contain multiple "values" in a single record (also known as a "nested table structure")
  • the data is described by the (optional) data dictionary (rather than being prescribed by a schema)
• the query language is not SQL (although some multi-value databases support SQL)

Multi-Value databases currently available include:

OpenQM

This site gives particular emphasis to OpenQM. OpenQM is a lightweight (~11 MB download) database offering high performance, unique features, and a low price.

This site has two books on the OpenQM database available for download (no cost, no registration - just send a message of thanks if you find these useful).

These books aim to answer the frequently asked questions:

• What is a multi-value database?
• Where do I get a copy?
• How do I install this software?
• What do I do now?

Getting Started in OpenQM - Part 1 outlines how to install the OpenQM database, how to create data files and dictionary files to describe the data, and how to query the database. This is formatted in two alternative page sizes: A4 (International) and Letter (North America) .

Getting Started in OpenQM - Part 2 shows how to write programs using the inbuilt programming language, and how to create a GUI application using the AccuTerm terminal emulator.

While these books have been written primarily for the OpenQM database, given the similarity between the above database products, you could use these books to learn any of the above databases - particularly UniVerse or UniData (as OpenQM is very similar to these products).

qmExplorer is a File explorer application for use with OpenQM:

The help file can be downloaded from here to preview how to install and run the application. Download links follow:

• Windows clients
• Linux clients

GPL version

An early version of OpenQM was released under the GPL licence. The following download links relate to this version:

• Installation instructions (Ubuntu)
• Patched source code
• Help files
• Documentation

Articles

Occasional articles may be posted in the Articles page.

Multi-value Resources