PostgreSQL

PostgreSQL is a sophisticated Object-Relational DBMS, supporting almost all SQL constructs, including subselects, transactions, and user-defined types and functions. It is the most advanced open-source database available anywhere.

The home page for PostgreSQL is http://www.postgresql.org.

PostgreSQL Information

There is a great deal of PostgreSQL documentation available, but among the most helpful is the book, PostgreSQL: Introduction and Concepts, by Bruce Momjian. The full text of the book is available online here: http://www.ca.postgresql.org/docs/awbook.html.

Another book in progress, to be published soon by O'Reilly & Associates, is Practical PostgreSQL. It also has the full text available online (for the moment, it is unclear if it will remain there after publishing) and can be found here: http://stage.linuxports.com/projects/postgres/book1.htm

Using PostgreSQL with Tavi

I you want use PostgreSQL instead of MySQL with Tavi, look at TaviPatches/PostgreSQLSupport page.