This article is from the Threads Programming FAQ, by Bryan O'Sullivan email@example.com with numerous contributions by others.
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.