in reply to Preventing SQL injection attacks: are -T and placeholders not enough?
I don't know what database system you are using. However, I would nearly always suggest holding your SQL within a stored procedure held within the database. The stored procedure will not execute unless the variables meet the data types set in the stored procedure. It has other potential added security benefits also.
Incidentally, I have not heard about -T for taint checking. I'll do some research on that - sounds interesting.
Update : I don't use taint checking because I don't use CGI. I have an interface layer that processed requests that come in, in the form of flat files. These flat files are checked for malicious looking requests. I place conditions that the requests have to meet and I actively look for malicious looking requests. Both positive and negative screening, if you like. That might be another approach.