Migrazzjonijiet tad-database (bidliet fl-iskema) huma waħda mill-aktar partijiet trickiest tal-CI/CD — b'differenza mill-kod tal-applikazzjoni stateless, id-databases jżommu stat li ma jistax sempliċement jinbidlu jew jitirġgħu lura. Immaniġġa migrazzjonijiet b'attenzjoni (awtomazzjoni, kompatibilità ħamsa, xejriet siguri) hija essenzjali għad-deployments affidabbli.
Għaliex il-migrazzjonijiet tad-database huma diffiċli
App code is stateless (replace it, roll back freely). DATABASES hold STATE:
→ can't just "roll back" a migration that dropped a column or transformed data
(the data may be gone) → rollbacks are risky/impossible for destructive changes
→ during deployment, OLD and NEW app code may run SIMULTANEOUSLY (rolling deploy) —
both must work with the database schema at that moment
→ Schema changes need careful coordination with code deployment.
