Cannot drop constraint with postgres even using adminer or sql command CONSTRAINT DOESN'T EXIST

Question

I cannot drop a constraint in postgres even using adminer

ALTER TABLE table_name
DROP CONSTRAINT constraint_name;

Error in query : ERROR: constraint "constraint_name" of relation "table_name" does not exist

but if I create a new one like :

ALTER TABLE table_name
ADD CONSTRAINT my_new_constraint(column1, column2, ... column_n);

Then it works and I can drop it.

The one who made the constraint I try to drop did it this way two years ago:

create unique index constraint_name on table_name (column1,lower(column2),coalesce(deleted_at,\'19000101\')

If anyone has got any idea to drop this constraint?

What is your intention here: coalesce(deleted_at,\'19000101\') ? — joop
– joop, Commented Jan 21, 2020 at 13:47
I have just tried to drop the index using this and it worked !!! Thank you ``` — Newon
– Newon, Commented Jan 21, 2020 at 13:50

Bergi · Accepted Answer · 2020-01-21 13:48:22Z

2

CREATE UNIQUE INDEX creates an index that needs to be dropped with DROP INDEX, not a table constraint.

answered Jan 21, 2020 at 13:48

Bergi

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