The following web sites provide additional information about the various vendors covered in this book:
The corporate resource for MySQL is http://theoryx5.uwinnipeg.ca/mysql. A great developer resource with lots of useful tips is Devshed.com: see http://www.devshed.com/Server_Side/MySQL/ for MySQL-specific information.
The official Microsoft SQL Server web site is http://www.microsoft.com/sql/. Microsoft also hosts a strong technical site for SQL Server at http://www.microsoft.com/sql/default.asp. Another good resource is found at the home of the Professional Association for SQL Server (PASS) at http://www.sqlpass.org.
The home for this open source database is located at http://www.postgresql.org. This site contains a great deal of useful information available for download, as well as mailing lists that enable exchanges with other PostgreSQL users. Additional PostgreSQL sites worth investigating are http://www.pgsql.com and http://www.GreatBridge.com, which offer support for commercial customers.