Application Development Software

Hello everyone. When we check-in a document in UCM, it inserts a row in Revisions table (and also in docMeta and Documents tables) in the database. The primary key for revisions table is dID. Can anyone tell me where is this dID generated. Let's take an example:

I insert a row in revisions table, docMeta and Documents tables manually with dID = X (say). from the front-end i can find the file and everything works fine. However when i check-in a document now it throws an error because it is again trying to insert into the revisions table with dID = X. I tried to find if there is a sequence but apparently it is not using any sequence or at least i couldn't find one.

So how is this dID generated? I would highly appreciate some pointers.

Regards,
Sadik Bhimani