In data base testing, you can check if the data is inserted, updated, deleted correctly or not. Also can check if data is retrieved correctly. Win Runner provides an option called Data base check wizard using which data base can be checked using sql queries.
its also worth looking for locks on data and contentions with multiple users. Also it is worth looking at the performance and ensuring that it copes under load.
For a good paper (though it also pushs a tool as well as an approach) check the www.embarcadero.com site and look up the papers on extreme test, Paul Down one of thier technical guys has done a good paper on Goals Based testing focussing on Databases .
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