Alvaro Herrera <alvherre@commandprompt.com> writes:
> The reason it's not supported in table_constraint, IIUC, is that the
> standard doesn't allow it, and that syntax is standards-mandated.
The real problem is not so much extending the syntax as that there'd be
no way to represent the constraint in information_schema. Exclusion
constraints are outside the standard already, so omitting them from the
information_schema views is less bad than missing unique constraints
would be.
regards, tom lane