Files
magnus919_agent-skills/data-engineering/references/database-migrations.md
T
Magnus HedemarkandGitHub c7c4d3b74f Port 11 methodology skills from hermes-profiles (#69)
Engineering: backend-engineering, frontend-engineering, data-engineering,
ml-engineering, platform-engineering, qa-methodology

Executive: go-to-market, legal-strategy, operational-design, org-design,
product-strategy

ml-engineering: added missing training-infrastructure.md reference
qa-methodology: added test-data-management, performance-testing,
security-testing references

All frontmatter converted to agent-skills convention.
Source: https://github.com/magnus919/hermes-profiles
2026-07-21 00:58:26 -04:00

1.1 KiB

Database Migrations

Migration Types

Type Risk Rollback Example
Add column (nullable) Low Trivial ALTER TABLE ADD COLUMN x TEXT
Add column (NOT NULL) Medium Trivial if default provided ALTER TABLE ADD COLUMN x INT NOT NULL DEFAULT 0
Rename column High Requires migration Two-phase: add new, dual-write, backfill, drop old
Drop column High Requires restore Verify no readers first, soft-delete before hard-drop
Create table Low Trivial CREATE TABLE
Drop table Critical Requires restore Verify no readers, triply confirm
Data migration High Requires rollback script Transform values, update references

Migration Checklist

  • Migration reviewed by another engineer
  • Rollback script exists and is tested
  • Downtime window confirmed (if required)
  • Read replicas considered (replication lag)
  • Foreign key constraints handled
  • Indexes created after data load (not before)
  • Migration tested against copy of production data
  • Query performance verified post-migration