subselects in check clauses
I have a need to check if a certain condition holds for all rows that
matches a given criteria. But postgresql appearently doesn't support
subselects in check clauses. Here is an example:
CREATE TABLE example (a int, b date, c date
CONSTRAINT csname CHECK (1 >= ALL (SELECT count(*)
FROM example
WHERE age(now(),b) > '0:0'
AND age(now(),c) < '0:0'
GROUP BY a)));
CREATE
INSERT INTO example VALUES (0,'2001-3-01','2001-12-12');
ERROR: ExecEvalExpr: unknown expression type 108
What can I do?
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Rasmus Resen Amossen | stud.mat.dat at the University of Copenhagen
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On Mon, 4 Jun 2001, Rasmus Resen Amossen wrote:
I have a need to check if a certain condition holds for all rows that
matches a given criteria. But postgresql appearently doesn't support
subselects in check clauses. Here is an example:CREATE TABLE example (a int, b date, c date
CONSTRAINT csname CHECK (1 >= ALL (SELECT count(*)
FROM example
WHERE age(now(),b) > '0:0'
AND age(now(),c) < '0:0'
GROUP BY a)));CREATE
INSERT INTO example VALUES (0,'2001-3-01','2001-12-12');
ERROR: ExecEvalExpr: unknown expression type 108What can I do?
You can probably fake it by doing the check inside a trigger on
insert, update and delete.