Free Database Roundup

This is not a comprehensive list, but a rundown of the most popular free databases available today. Each of these databases has its own strengths and limitations (either technical or with the licensing), so please choose carefully.

• IBM DB2 Express-C - Find a review of it here. I am currently running it on my laptop, primarily for use with IBM Cognos 8 Business Intelligence. I have posted an install guide, and a guide to setting up the Cognos 8 samples on it.
• Oracle 10g Express - A starter Oracle database. Resources and comparisons with the other free databases can be found here on TechRepublic.
• Sybase ASE Express - The free version of Sybase ASE is only available for Linux. The developer edition is available for other platforms, but it has much more restrictive terms of use.
• SQL Server 2005 Express - A light version of SQL Server for desktops, small servers and for embedding into applications. Lots of good resources here on the Microsoft site.

Open source databases

• Apache Derby - A small Java relational database which can be embedded or used in client - server mode. IBM Cognos 8 BI Server ships with Apache Derby for use as the default content store, which shortens the time to getting a demo or dev server up and running.
• Berkeley DB - Now distributed Oracle after their acquisition of SleepyCat. Berkeley DB is an embedded database with three separate editions: the original relational database, written in C, a Java
  version and an XML edition.
• MySQL - The “M” in LAMP. This database is behind many web applications, including WordPress and Wikipedia. MySQL is now owned by Sun Microsystems.
• PostgresSQL - A mature and well supported open source relational database.
• SQLite - As the name implies, a featherweight and self-contained database. It is designed for embedding into applications, in particular applications on mobile devices.

Other free database resources:

• Azzurrie Clay - a data modeling plugin for Eclipse.
• Freebyte’s guide to free databases - a more comprehensive list of open source databases and free database programming libraries.
• Getting started with the NetBeans Database Explorer.
• Free data models to help get started on database schema development.
• QuantumDB - an open source Eclipse plugin for database development.
• SQL Explorer - another Eclipse plugin for database development.