Can anyone tell me who developped SQLdb framework for lazarus?
It is a combination of many people, but I think nowadays it is Michael van Canneyt that does most of the database related development for FPC.
As for Thaddy's comment about the unit header comment - those can not be relied upon. They are 90% of the time way out of date. Better look at the source code commit log, but even that is unreliable, because SubVersion (what FPC project uses) doesn't distinguish between the person that created the code changes/patches and the person that committed the patch. The FPC team doesn't give out commit access very easily. Git on the other hand tracks how created the patch and how committed the patch.