U129: Cannot drop table / Cannot drop object

Example Postgres Log Output:

ERROR: cannot drop table x because other objects depend on it
DETAIL: view a depends on table x
HINT: Use DROP ... CASCADE to drop the dependent objects too.
STATEMENT: DROP TABLE x

Explanation:

A request was sent to drop a specific database object (e.g. a table), but it couldn't be completed, usually due to other objects still depending on it.

You will likely encounter this when using foreign keys and deleting tables in the wrong order during regular development/staging operations, or when cleaning up an old data model in production.

Sometimes this error message may also be encountered if you try to drop an internal object in the Postgres system which can't be dropped.

Recommended Action:

Review the dependencies to and from the involved object carefully, and drop them in the correct order.

Sometimes you may also utilize the CASCADE option to have this dependency resolution by done automatically - but be careful, since cascading can also lead to unintended objects being dropped.

Always use a transaction when using complex DDL like DROP with CASCADE, and verify whether any problematic tables that are referenced e.g. via a foreign key constraint were not affected negatively by the command, before running COMMIT.

Learn More:

• Postgres Documentation: SQL Commands - DROP TABLE
• Postgres Documentation: Data Definition - Dependency Tracking