Open source databases come with the advantage of being free, available for understanding, modification, and improvement as per needs.
There are three ways of using an open source database - do-it-yourself, thirdparty, and outsourcing. The choice of an open source database depends on factors, such as the intended usage, duration of use, and the cost involved as the main factor. Often the best comparison is obtained by first-hand evaluation.
Players: The top three vendors in the database market are: Oracle, IBM (DB2 and Informix), & Microsoft (SQL Server). In the open source market, there are six important
players (on the basis of acceptance in the software community
1. MySQL - GNU (General Public License) as well as commercial
2. PostgreSQL - BSD (Berkeley Software Distribution)
3. Firebird - Initial Developer's Public License (IDPL)
4. Ingres - GNU General Public Licensev2
5. MaxDB (earlier known as SAP DB, it is being developed in alliance with MySQL especially for SAP environments) - GPL
6. HSQLDB - BSD license
The popularity of an open source database seems like a trivial concern to the technical community, but the fact stands tall that a products success is based on other reasons in addition to the technical features. Some of these are:
a) Support available from community as well as tool vendors
b) Momentum of the product being released in and open source arena
These are the two most important business concerns for choosing an open source product. The former ensures integrity with various other technologies and the latter ensures that open source is not going to die or fade out easily.
The six open source databases that we selected fare differently on the popularity aspect.
MySQL - most popular open source database boasting more than 8 million active installations. Starting since 95 (internally), the MySQL community is the largest and has frequent releases; version 4.1 came out in Apr-03, current version 5.0 in Aug-04, and the much-talked and awaited future release version 5.1 is out as beta since Nov-05.
PostgreSQL - has hundreds of companies listed as Users. The community is as old as Aug-96. It is much-adored among technical jig wigs for its huge support of features.
EnterpriseDB is a product built over it. Last few releases have been version 7.4 in Nov-03, current version 8.0 in Jan-05, and the new release 8.1 in Nov-05.
Firebird - about 0.1 million deployments as of Sep-05. This is a very old community since Sep-84 and has a huge fan following for the number of good and bad times it has been through. The versions out are version 1.0 in Mar-02, current v1.5 in Feb-04 and 2.0 alpha is out there.
Ingres - about 5000 existing customers. After changing many hands, the product has been made available to open source since 04, though it has been in existence along with
PostgreSQL. The current release - r3 is out since Aug-04 and r4 is much-awaited for its support to materialized views.
MaxDB - about 6000 customer installations. This has been specific to Mobile application development earlier known as SAPDB. Started since Oct-00. It was available in version 7.6 in Nov-05
HSQLDB - 0.3 million downloads. The project is finding hard to get contributions and is slower than others. It is the youngest in the group, formed since 01. It released 6 versions since Apr-01. Platform Support also speaks about the popularity and acceptance. Regarding the OS, we have major players as Linux, UNIX, Apple, and Windows. Besides, we also have Novell with Netware and BSD.