Subject Re: [Firebird-Architect] Re: Nulls in CHECK Constraints
Author Ann W. Harrison
Alex Peshkov wrote:
> Should not we clarify one aspect of cross-table constraints.
(Excellent example deleted. Essentially it's a cross table
constraint for table T2 depending on values in T1. Changing
T1 allows the constraint to be violated without error.)
> Is it up to standard that enabling cross-table check constraints makes
> it virtually impossible to strictly follow them?

My understanding - and it's probably very flawed - is that the
constraint applies to the table on which it is defined and is
checked after operations on that table. Changes to other
tables may cause problems, but that's outside the scope of the

That makes a certain amount of sense. If I have a table T1 and
give you read access to it, and you create a table T2 that has
a constraint based on values in T1, you shouldn't be able to
constraint my table, should you?