> > What are the opinions about this?
>
> The Firebird behaviour violates the standard.
>
> > What does the standard say?
>
> "A table check constraint is satisfied if and only if the specified

<search

> condition> is not False for any row of
> a table". And Unknown is not False.
>
> > What do other databases implement?
>
> PostgreSQL and MSSQL are standard compliant, i.e. they follow the Oracle's
> line of thinking.

I would also say that "not null"-ness is a column constraint, not a
row constraint...

With regards,

Martijn Tonies
Database Workbench - tool for InterBase, Firebird, MySQL, Oracle & MS SQL
Server
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