Postgresql is free, it is less encumbered, possibly, than MySQL in the long run. Postgresql is more totally Open Source, whereas MySQL is owned by Sun Microsys

Postgresql is free, it is less encumbered, possibly, than MySQL in the long run. Postgresql is more totally Open Source, whereas MySQL is owned by Sun Microsystems. And it is not free for all commercial cases. Postgresql is. MySql gets its speed rep from the 'MyIsam' table type. But you don't want that for financial data. You want a stronger database. They have another several table types that are more robust and standardized, but not as fast. Postgresql is plenty fast for large installations when well tuned. And it has good referential integrity, a long-enough history so you can trust it, and stored procedures. MySql is simpler to get started with. I've never heard that SQL Server was faster, but I'd estimate they have very nice integration with .NET, as it's the same company. This nice integration will undoubtedly lock you in to using their database forever, though. And who knows how their price will change? Whichever you choose, you will gain if you have at least one person around who has used the DB before and (for MySQL) table-type before. Even once in a while. Paid consultants are available for any database you choose.