Error 2BP01 occurs when you try to drop or alter an object that other database objects still reference.
PostgreSQL Error 2BP01 dependent_objects_still_exist appears when you attempt to DROP or ALTER an object that another table, view, index, or constraint still depends on. Remove or modify the referencing objects first, or use CASCADE, to resolve the error.
PostgreSQL Error 2BP01
Error 2BP01 fires when PostgreSQL refuses to drop or alter a database object that still has dependent objects. The engine protects referential integrity by stopping the command and returning dependent_objects_still_exist.
Developers usually meet this error while cleaning up schemas, renaming columns, or rebuilding tables.
Fixing it promptly avoids broken views, failed migrations, and application downtime.
The error always arises from an attempted DROP or ALTER on an object that another object references. Typical references include foreign keys, views, materialized views, indexes, rules, and triggers.
PostgreSQL runs a dependency check before executing structural changes.
If any dependency chain remains, it throws 2BP01 instead of silently corrupting metadata.
Identify all dependent objects with pg_depend and pg_constraint or the \d + ppsql meta-command. Decide whether to drop, alter, or re-create those objects.
Safest path - remove or update dependents manually, then re-run your original DROP or ALTER.
Quick path - append CASCADE to the statement to let PostgreSQL automatically drop every dependent object.
Dropping a column blocked by a foreign key - drop or disable the foreign key first, or use ALTER TABLE .. DROP COLUMN ..
CASCADE.
Removing a table used by a view - drop the view or ALTER it to stop referencing the table, then drop the table.
Renaming a type used by other tables - either update each table to the new type or create a new type and migrate data.
Design schema changes in dependency order - update or drop children before parents.
Use Galaxy collections to store vetted DDL scripts.
Team review spots hidden dependencies before code reaches production.
Automate dependency scans in CI with queries against pg_depend to fail builds early when risky changes appear.
42704 undefined_table - occurs when an object you referenced does not exist. Fix by creating or spelling the object correctly.
42703 undefined_column - raised when a selected column is missing. Confirm column names after any renames.
42P07 duplicate_table - appears when creating an object that already exists.
Either drop the duplicate or use IF NOT EXISTS.
.
CASCADE is safe when you are sure all dependent objects are obsolete. In production, audit each dependency first.
Use \d+ object_name in psql or query pg_depend joined with pg_class for readable names.
No. VACUUM cleans dead tuples but does not modify dependency metadata.
Yes. Galaxy run history and role based permissions let teams review DDL scripts before execution, reducing accidental data loss.
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