Обсуждение: Does postgresql know the check condition is valid or not. or can check deduce from multiple conditions
If the question is stupid, please tell me why.
postgresql - How to query check the constraint is valid or not - Stack Overflow
Postgres 14 | db<>fiddle (dbfiddle.uk)
CREATE TABLE emp (test_check int check ( test_check >1 and test_check < 0 ));
alter table emp VALIDATE CONSTRAINT emp_test_check_check;```
select * from pg_constraint where conname = 'emp_test_check_check';
Even with the above mentioned step, does postgresql know above check constraint condition always false.
another similar question:
can postgresql deduce from
CREATE TABLE emp1 (test_check int check ( test_check >1 and test_check > 10 ));
to
CREATE TABLE emp1 (test_check int check ( test_check > 10 ));
Jian He <hejian.mark@gmail.com> writes: > CREATE TABLE emp (test_check int check ( test_check >1 and test_check > < 0 )); > Even with the above mentioned step, does postgresql know above check > constraint condition always false. No, not explicitly. If the constraint always fails, that is your problem not Postgres'. regards, tom lane
Re: Does postgresql know the check condition is valid or not. or can check deduce from multiple conditions
If the question is stupid, please tell me why.
CREATE TABLE emp (test_check int check ( test_check >1 and test_check < 0 ));
alter table emp VALIDATE CONSTRAINT emp_test_check_check;```
select * from pg_constraint where conname = 'emp_test_check_check';
Even with the above mentioned step, does postgresql know above check constraint condition always false.
another similar question:
can postgresql deduce from
CREATE TABLE emp1 (test_check int check ( test_check >1 and test_check > 10 ));to
CREATE TABLE emp1 (test_check int check ( test_check > 10 ));