> What are the opinions about this? What does the standard say? What do
> other databases implement?

One other thing about our Check Constraints:
They allow access to other tables.

This is prohibited in the SQL (2003) standard, as a check constraint
should be a row constraint.

I guess this is an implementation error, given that Firebird check
constraints aren't evaluated completely if, for example, you delete
a row in the table.

The SQL standard says, I believe, that there's an "assertion" object
which can be used for table or database (multi-table) constraint.

With regards,

Martijn Tonies
Database Workbench - tool for InterBase, Firebird, MySQL, Oracle & MS SQL
Server
Upscene Productions
http://www.upscene.com
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