Database Wisdom: Reference - Free Database Downloads

If you do not already have a database in mind, there are plenty of free databases you can download from the Internet to play with.

Oracle Express * Recommended Download

I have a preference for Oracle. It is a robust, stable and powerful database. You can get the free Express Edition (XE) directly from Oracle. Oracleoffers plenty of tutorials on the OracleTechnology Network. Oracle XE is a limited database. That means that you can run it on any computer but it will only take advantage of 1 CPU, 1GB of RAM and will only access up to 4GB of disk. There are also some enterprise features missing. For a learning database though, I fully recommend it.

The Oracle documentation is excellent. Support via multiple community forums, email lists and wikis.

Oracle 10g Express Edition Home Page

Oracle 10g Express Edition Download

Oracle 10g Express Edition Documentation

Oracle 10g Express Edition: Not Just For Learners (written by me)

MySQL * Recommended Download

MySQLis a widely used open source database. It has a very low cost of entry and a very high ease of use factor. As a matter of a fact, I believe it has the market share that it does strictly because it is so easy to install and use. For someone new to databases, MySQL is a very good choice.

Documentation is decent. Community and forum support is robust.

MySQL Home Page

MySQL Download

MySQL Documentation

MySQL Community OurDelta - OurDelta.com provides downloadable binaries that inlcude patches from third parties such as Google and Percona. These patched binaries may be more stable and/or performant than the community version avaialable from MySQL.

OurDelta.com Home Page

OurDelta.com Downloads

OurDelta.com Documentation

Postgres

Postgres is another, less widely used, open source database. It is fairly easy to install and use, although no where near as easy as MySQL. It is a more enterprise-class database than MySQL but as a learning database, it falls short.  

Postgres documentation is decent but community support is via email lists.  

Postgres Home Page

Postgres Download

Postgres Documentation

MS SQL Server Express

Microsoft's SQL Server is the database many people are referring to the SQL database. Microsoft offers an Express edition much like Oracle's (with the same limitations). Microsoft, love them or hate them, they are everywhere. If you are going to be developing purely for windows (probably with .Net) and are planning to use Visual Studio, SQL Server is a good choice. Otherwise, go with Oracle or an open source database.  

SQL Server Express Edition Home Page

SQL Server Express Edition Download

SQL Server Express Edition Support

DB2 Express

Not to be outdone, shortly after Oracle released their Express Edition, IBM followed suit with DB2 ExpressEdition (with limited CPU and memory but unlimited disk space). Like Oracle and SQL Server, DB2 is not an open source database. Unless you are working for a company that uses DB2 and want to be completely compatible, there is really no good reason to use DB2. Oracle is a more robust, reliable and scalable database that costs about the same (when you move beyond express editions).  

DB2 Express Home Page

DB2 Express Download

Db2 Express Documentation

Firebird

To round out the open source offerings, here is Firebird. Firebird is not nearly as common as MySQL but has a very strong community of supporters. Enterprise features fall just short of Postgres but Firebird is easier for new users.

Documentation is sparse and incomplete.

Firebird Home Page

Firebird Download

Firebird Documentation

Ingres

And finally, Ingres. Ingres has been around for a very long time and has changed hands multiple times. Its latest incarnation is as an open source database. Ingres is probably the most advanced open source database and offers some features that are normally only available in commercial databases. Unfortunately, it is not used very extensively outside of certain circles and still lacks some features I consider basic (although they are working on that).

Ingres offers exceptional documentation and a very nice community online.

Ingres Home Page

Ingres Download

Ingres Documentation