Does any DBMS vendor provide a thread-safe interface?
Oracle 7.3 and above provide thread-safe database client interfaces, as do Sybase System 11.1 and above, and Informix ESQL 7 and above. If you are still using an older release of any of these products, it is possible to hack together a set of intermediate thread-safe interfaces to your database if you really need it, but this requires a moderately large amount of work.