Training is also available on a wide variety of topics for both PostgreSQL and MySQL. MySQL AB provides training in cities around the world, with topics ranging from administration to writing Web-based applications using MySQL. PostgreSQL training is also available from dbExperts and Big Nerd Ranch.

Who Else Uses Them?
A number of large companies use both open-source databases in various ways. Both database engines have somewhat large database installations in use. I use the word somewhat because data storage is a relative term. Oracle and DB2 can scale to terabytes of data storage fairly easily. MySQL and PostgreSQL are known to run well into the hundreds of gigabytes, but few companies use the databases above that range.

Cox Communications uses MySQL to manage information related to its cable modem business. NASA uses MySQL to store information about public contracts. Slashdot, a widely read online publication, uses MySQL to store all of the information related to its site. The Associated Press uses MySQL to serve various types of information, including access to the U.S. Census and Olympic results.

You probably use PostgreSQL indirectly on a fairly regular basis. Afilias, which manages the .ORG registration, uses PostgreSQL to store all of .ORG registry information. The American Chemical Society uses PostgreSQL to store documents that exist only within that database. BASF uses PostgreSQL in a shopping platform for its agriculture products. The World, a media company, has built much of its infrastructure around the use of PostgreSQL.