Rollback

How it works

Before each migration run, schema-flow captures a MigrationSnapshot in _smplcty_schema_flow.snapshots. This records the operations that were applied.

schema-flow down computes reverse operations from the latest snapshot and executes them.

Usage

# Rollback the last migration
npx @smplcty/schema-flow down --db postgresql://user:pass@localhost:5432/mydb

Reversible operations

Forward operation	Reverse
create_table	DROP TABLE
add_column	DROP COLUMN
add_index	DROP INDEX
add_foreign_key	DROP CONSTRAINT
add_foreign_key_not_valid	DROP CONSTRAINT
add_check	DROP CONSTRAINT
add_check_not_valid	DROP CONSTRAINT
add_unique_constraint	DROP CONSTRAINT
create_enum	DROP TYPE
create_function	DROP FUNCTION
create_trigger	DROP TRIGGER
drop_trigger	CREATE TRIGGER
create_policy	DROP POLICY
drop_policy	CREATE POLICY
create_view	DROP VIEW
create_materialized_view	DROP MATERIALIZED VIEW
enable_rls	DISABLE RLS
create_extension	DROP EXTENSION
create_role	DROP ROLE
grant_*	REVOKE

Irreversible operations

These are skipped during rollback (no data loss from rollback itself):

• alter_column – column type/default changes cannot be safely reversed
• add_enum_value – PostgreSQL cannot remove enum values in a transaction

Programmatic API

import {
  ensureSnapshotsTable,
  saveSnapshot,
  getLatestSnapshot,
  listSnapshots,
  deleteSnapshot,
  computeRollback,
  runDown,
} from '@smplcty/schema-flow';