>> Until now I'm checked the table its normal again.
> I'm having a little trouble parsing that sentence ... and the semantic
> analysis is going even worse.
What I meant is that I don't know from the sentence above whether things
are OK, or not, or were once OK and now aren't. The dates associated
with the bad records are a couple of weeks ago, so it doesn't sound as if
you had check the data regularly and just recently found it bad.
>
> What when insert or else ? Can show and tell me this trouble because my code ? Connection or ?
>
No, my comment had nothing to do with your code. It's unlikely that Firebird is
randomly introducing nulls when it should not, so there's probably something
different about the way the bad values were created. One way to figure it out
is to compile a debugging version of Firebird that tests specifically for the
insertion of nulls to that field in that table, set a breakpoint, and
look backward
to see where the problem starts.