Wanted: Info about performance-comparison of SQL-databases

Hello People !

I am just beginning my diploma-theses in which I first have to prepare the decission which commercial database-software a bank has to buy. The database-software should have network-ability and should provide a SQL-slang.
The Network should have about 300 users in a later version.

I now have got following Questions:

( 1 ) Which database-software can be recommended?

( 2 ) Under which operating-system/ hardware configuration has the

       database the best performance?

( 3 ) How can I compare the performance of different databases (running

       on the same configuration) ?

The database should be able to work with about 2 Gbyte data.

Please send your response to  

       wpenschk_at_mathematik.uni-ulm.de
       (Walter Penschke/Ulm)