Hi,

> i was only thinking that if you have several write-authorised users
> simultaneously connected to a database and user 1 for instance
> modifies an entry in transaction 1 while user 2 deletes the exact same
> entry in transaction 2, you would end up with inconsistent data..

it seems that you are lacking some basic concepts of Transactions,
Databases and the ACID properties. I suggest you to read something about
these topics first. I'm afraid I cannot offer you a concrete link or
book suggestion though.
Does the Firebird book by Helen talk about these topics?