Alternatives to MySQL
Of course, there are many alternatives to MySQL, particularly if you are prepared to pay (lots of) money for licenses and perhaps also for the requisite hardware. Among these are IBM DB2, Informix, Microsoft SQL Server, and Oracle.
If you are looking for a database in the open source realm, then PostgreSQL is currently perhaps the most interesting alternative. However, be warned: The discussion between advocates of MySQL and those of PostgreSQL usually resembles more a war of religions than what might be termed measured intellectual discourse. In any case, PostgreSQL offers more functions than MySQL (even if MySQL is slowly catching up). At the same time, PostgreSQL is considered slower and less stable (even if in this regard the reputation of PostgreSQL has greatly improved).
For small database solutions (also in the sense of saving memory) you might consider SQLite. This is a tiny library (about 250 KB binary code) that is available for elementary database functions. SQLite is available free of charge even for commercial applications and is especially suited for stand-alone solutions (less for network applications). SQLite is moreover integrated into the current versions of PHP.
There are also several formerly commercial database systems that have been converted to open source. The best known of these is Firebird, formerly Interbase from Inprise/Borland.
Finally, I refer you to the already mentioned database MaxDB, formerly SAP-DB. It is maintained and marketed by the firm MySQL but otherwise has little to do with the MySQL database system. MaxDB is a professional and comprehensive–database system that shares the drawbacks of large (commercial) database systems: complex installation, administration, and maintenance, and comparatively small user base and correspondingly small amount of documentation and help in the Internet.
MySQL is a very capable relational client/server database system. It is sufficiently secure and stable for many applications, and it offers an excellent cost/benefit ratio (not only because MySQL is free itself, but also because it makes comparatively modest demands on hardware). MySQL has thus developed into a quasi standard in the realm of Internet databases.
Above all, in the Linux world, MySQL is used increasingly by applications as the background database engine, whether it be managing logging data more efficiently than previously or managing email, MP3 files, addresses, or comparable data. MySQL is poised to play a similar role to that of the Jet Engine in the Microsoft operating system (where in many respects, MySQL offers a meaningfully better technical basis). Thanks to the ODBC interface, MySQL is now being used in the Windows world for such tasks.
Apart from technical data, MySQL has the advantage over other open source database systems in that it is by far the most widely used such system. It follows that MySQL has been more thoroughly tested and documented than other database systems and that it is relatively easy to find developers with MySQL experience.
However, MySQL cannot (yet) compete in every respect with the big boys of the commercial database system world. You are not likely to choose MySQL if you require functions that MySQL does not yet support. The decisive question is, then, Is MySQL good enough for my application? Not only millions of Web site developers, but also firms and organizations such as Associated Press, Citysearch, Cox Communications, Los Alamos National Labs (7 terabytes of data), Lycos, NASA, Sony, Suzuki, Wikipedia, and Yahoo! have answered this question in the affirmative. If you choose MySQL, you will be in good company.
The above tip is excerpted from from Chapter 1, "What is MySQL?" of The Definitive Guide to MySQL 5 by Michael Kofler, courtesy of Apress. Find it helpful? Purchase the book here.
About the author: Michael Kofler holds a Ph.D. in computer science from Graz Technical University. He has written a number of successful computer books on topics such as Visual Basic, Visual Basic .NET, and Linux. Michael is the author of The Definitive Guide to MySQL 5, Third Edition and Definitive Guide to Excel VBA, Second Edition from Apress.