How to view contraints of a cloumn in postgresSql?
-
01-03-2021 - |
Domanda
I applied a constraint but forgot its name. Now I want to drop it using ALTER TABLE [TABLENAME] DROP CONSTRAINT [CONSTRAINTNAME]
. If there is a way to drop all constraint from a column that should work too.
I cannot use psql command.
Soluzione
PostgreSQL exposes the constraints as well as other schema details through information_schema
, so to find all the constraints for the table, query table_constraints
, for example:
SELECT constraint_name FROM information_schema.table_constraints
WHERE table_name='my_table' AND constraint_type='UNIQUE';
To find which columns are involved into the constraints, check constraint_column_usage
.
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