2011/7/18 Tom Lane <tgl@sss.pgh.pa.us>:
> Josh Berkus <josh@agliodbs.com> writes:
>> Tom,
>>> No, I don't. You're adding complication to solve a problem that doesn't
>>> need to be solved. The standard says to return the name of the
>>> constraint for a constraint-violation failure. It does not say anything
>>> about naming the associated column(s). COLUMN_NAME is only supposed to
>>> be defined for certain kinds of errors, and this isn't one of them.
>
>> Are we talking about FK constraints here, or CHECK contstraints?
>
> Either one. They both have the potential to reference more than one
> column, so if the committee had meant errors to try to identify the
> referenced columns, they'd have put something other than COLUMN_NAME
> into the standard. They didn't.
Personally, I see a sense for COLUMN_NAME field only with relation to
CHECK_CONSTRAINT - for any other constraint using a COLUMN_NAME is
based on parsing a constraint rule - and I don't believe so the
standard is based in it. Column check constraint is attached
explicitly to one column - but this relation should not be based on
semantic.
We can check DB2 implementation.
Regards
Pavel
>
> regards, tom lane
>
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