Inspect the current state
Inspect the table, constraints, references and application readers. Check that proposed column names come from the real schema. Understand any discrepancy between migration records and the database before planning more changes. Do not declare a change applied merely to make a history listing look consistent.
Check existing rows against new rules
Before adding required or uniqueness constraints, inspect missing and duplicate values. Plan how existing records become valid. Success on an empty database does not establish that the same operation is appropriate for populated tables. Keep a migration test that represents the real data conditions without exposing private records unnecessarily.
Plan application compatibility
For column names or types, identify which application versions can connect during release. Consider separate stages for addition, data movement, application switch and cleanup. Review whether readers remain valid at each stage instead of requesting one large SQL script that assumes deployment happens everywhere at the same instant.
Verify in an appropriate copy
Use an appropriate test copy to check counts, references and application reads and writes before and after migration. Estimate runtime and interference under representative conditions. A tool reporting that SQL executed is not the final verification: exercise the application behavior the migration was intended to support.
Example: introducing a required field
When existing rows lack a new required field, consider addition, data completion and constraint application as separate stages. Filling missing values with an empty string is not automatically a valid migration. Define the real source of the value and review reads and writes during any period when an older application version can still connect.
Make recovery operational
A backup needs a restore destination, validation steps and a switch procedure. Reverse SQL does not necessarily recover discarded data. Consult the documentation for your actual PostgreSQL version and hosting environment, and require the responsible operator to explain the recovery path before authorizing a production release.
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- PostgreSQL table changesInformation checked: 2026-10-27
- PostgreSQL constraintsInformation checked: 2026-10-27
- PostgreSQL backup and restoreInformation checked: 2026-10-27
- Claude Code permissionsInformation checked: 2026-10-27
- Claude Code overviewInformation checked: 2026-10-27
- Claude Code costsInformation checked: 2026-10-27
- Cline overviewInformation checked: 2026-10-27
- Cline authorization and model accessInformation checked: 2026-10-27
- Cline local modelsInformation checked: 2026-10-27
- Aider usageInformation checked: 2026-10-27
- Aider chat modesInformation checked: 2026-10-27
- Aider models and keysInformation checked: 2026-10-27