How to delete/drop a constraint in PostgresSQL

This article will show you how to drop a constraint, such as a foreign key constraint, on a PostgresSQL 8.x database.

1. Login to the PostgresSQL command-line interface

psql -U [username] [database_name]

2. Show a list of constraints on a particular table

\d [table_name]

3. To Delete (or Drop) the constraint, use the command:

ALTER TABLE [table_name] DROP CONSTRAINT [constraint_name];