How do I install the Migrations skill?

Run npx skillmds@latest add omexit/migrations in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Migrations safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Migrations?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Migrations free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Migrations?

OmexIT (@omexit) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Migrations by omexit — Agent Skill

Name: Migrations
Author: OmexIT

File contents

Database migrations

House law (Postgres)

These defaults apply to service-owned schemas. Third-party and provider-managed schemas keep their own versioned contract.

PKs: BIGINT app-generated TSID, with UUIDv7 as a separate public identifier. Do not retrofit upstream package schemas or expose storage keys.
Audit fields by lifecycle: every business row records creation time and actor when an actor exists. Mutable rows also record update time and actor. Append-only rows do not pretend to update.
Money: NUMERIC(precision, scale) derived from the supported currency or asset contract; common two-decimal fiat may use NUMERIC(20,2), but not when the asset set needs another scale. Time: TIMESTAMPTZ for instants.
Closed enums: TEXT + CHECK; use a reference table when values evolve independently. Avoid native Postgres enums when rolling change is required.
Multi-tenant tables: use tested RLS when the service relies on database tenant enforcement, including ENABLE, normally FORCE ROW LEVEL SECURITY, and a policy based on the correctly typed current_setting('app.tenant_id', true) value.
Naming: <scope>-<NNN>-<description>.sql (Liquibase, established services) / timestamp versions (Flyway, newer services; avoids merge conflicts). Match what the repo already uses. Greenfield (unreleased) repos: edit the existing changeset instead of stacking history.

Zero-downtime rules

Two-phase renames (add → dual-write → switch → drop later).
CREATE INDEX CONCURRENTLY in its own changeset with transactions off (runInTransaction:false Liquibase / executeInTransaction=false Flyway); it cannot run inside a transaction block.
FKs as NOT VALID, then VALIDATE CONSTRAINT.
Destructive ops (DROP, TRUNCATE, column removal) require explicit user confirmation and a documented rollback story.

Backfills

Prefer a resumable application job for complex or long backfills. A PostgreSQL DO loop with per-batch commits is valid only when the exact runner executes it at top level outside a transaction: Liquibase puts runInTransaction:false on the --changeset line; Flyway uses executeInTransaction=false in script configuration. Irreversible changes have no fake rollback and must state restore or forward-fix steps. Pattern: references/backfill-pattern.md.

Verification

Fresh-container run must apply cleanly from scratch; rollback tested where reversible; ledger-table changes also satisfy the ledger skill invariants.

---name: migrationsdescription: Use when creating or reviewing database migrations - Liquibase or Flyway, new tables, columns, indexes, constraints, backfills, or any DDL against Postgres.---# Database migrations## House law (Postgres)These defaults apply to service-owned schemas. Third-party and provider-managed schemas keep theirown versioned contract.- **PKs**: `BIGINT` app-generated TSID, with UUIDv7 as a separate public identifier. Do not retrofit upstream package schemas or expose storage keys.- **Audit fields by lifecycle**: every business row records creation time and actor when an actor exists. Mutable rows also record update time and actor. Append-only rows do not pretend to update.- **Money**: `NUMERIC(precision, scale)` derived from the supported currency or asset contract; common two-decimal fiat may use `NUMERIC(20,2)`, but not when the asset set needs another scale. **Time**: `TIMESTAMPTZ` for instants.- **Closed enums**: `TEXT` + `CHECK`; use a reference table when values evolve independently. Avoid native Postgres enums when rolling change is required.- **Multi-tenant tables**: use tested RLS when the service relies on database tenant enforcement, including `ENABLE`, normally `FORCE ROW LEVEL SECURITY`, and a policy based on the correctly typed `current_setting('app.tenant_id', true)` value.- **Naming**: `<scope>-<NNN>-<description>.sql` (Liquibase, established services) / timestamp versions (Flyway, newer services; avoids merge conflicts). Match what the repo already uses. Greenfield (unreleased) repos: edit the existing changeset instead of stacking history.## Zero-downtime rules- Two-phase renames (add → dual-write → switch → drop later).- `CREATE INDEX CONCURRENTLY` in its own changeset with transactions off (`runInTransaction:false` Liquibase / `executeInTransaction=false` Flyway); it cannot run inside a transaction block.- FKs as `NOT VALID`, then `VALIDATE CONSTRAINT`.- Destructive ops (`DROP`, `TRUNCATE`, column removal) require explicit user confirmation and a documented rollback story.## BackfillsPrefer a resumable application job for complex or long backfills. A PostgreSQL `DO` loop with per-batch commits is valid only when the exact runner executes it at top level outside a transaction: Liquibase puts `runInTransaction:false` on the `--changeset` line; Flyway uses `executeInTransaction=false` in script configuration. Irreversible changes have no fake rollback and must state restore or forward-fix steps. Pattern: `references/backfill-pattern.md`.## VerificationFresh-container run must apply cleanly from scratch; rollback tested where reversible; ledger-table changes also satisfy the `ledger` skill invariants.

Frequently asked questions

Migrations