Carsten,

> Alexander,
> i think it is all right, what you have written, but it's not relevant for my case.
> (there was no data insertet in the database after my updates)
> I forget to define a default value.
> Why is there no error raised from the database, if this leads to unrestorable backups ?

When I insert a new field with NOT NULL but without a DEFAULT
value, then dependent on the used data type a value is inserted
for existing records automatically. e.g. 0 for Integer, empty
string for VARCHAR, ... so this shouldn't be the problem.

I'm using Firebird 1.0 Build 796.

What exact error message do you get during the restore?

Regards,
Thomas.