How to Write a PostgreSQL Migration from a Schema Delta
Migrations invent uuid-ossp and backfills. Lock Postgres version. Up and down from the delta only.
The matching generator is the PostgreSQL Migration from a Schema Delta Brief prompt. Browse related cards in the PromptDig library (Browse more prompts). When a filled run survives, share the version you actually use (Share a prompt).
Lock Postgres version first
Write a PostgreSQL migration from a schema delta brief. Never invent tables, columns, or extensions not listed. Start by filling Inputs, not by asking the model to remember last week's run. If a field is blank, write NONE or NOT IN INPUTS and leave it blank through Generate. The card is built so the model cannot honestly invent a number, owner, URL, or command that you did not paste.
Paste these fields before you hit run:
Schema delta brief: [Delta]
Postgres version I lock: [PGVer]
Migration tool I allow (or raw SQL): [Tool]
Words I must not use: [Banned]
What I must never invent: [Never]
Output format: [Format]
Language: [Lang]
That inventory is the honesty ledger. Anything that does not appear there is forbidden in the draft. If you catch yourself adding a nice-to-have after the run, you are no longer using the card. You are ghostwriting. Put the extra fact in Inputs and run again.
Number changes from the delta only
Generate is numbered on purpose. Do not skip a step because the first paragraph looked done. The early steps exist to stop later prose from smuggling claims.
Walk the Generate list in order:
- Honesty ledger: Delta nouns, PGVer, Tool, Lang.
- Version lock: PGVer.
- Change list numbered from Delta only.
- Up migration SQL. Only objects in Delta. If type missing, write TYPE UNKNOWN and stop that statement.
- Down migration SQL reversing only stated ups.
- Refuse: inventing extensions (uuid-ossp) if not in Delta, inventing backfill UPDATE data, inventing indexes not requested.
- Lock/timeout notes: only if Delta states; else LOCK NOTES NOT IN INPUTS.
- Compliance pass: Banned and Never. Format as Format.
If a step asks for a version lock, quote the version from Inputs in the output. If a step asks for a refuse list, keep the refuse list in the published artifact, not in a sidebar you delete. Reviewers should see what the model was not allowed to do.
Write up and matching down SQL
Most failures are the same shape: a missing field gets a confident fill. A conversion rate appears. A Gradle task appears. A flash point appears. A caption appears on a job that asked for slide text only. Your review is to search the draft for numbers, names, and commands, then grep Inputs. No match means cut.
Honor the constraints as hard stops, not vibes:
- Migration from Delta+PGVer only. Not an ORM scaffold.
- Never invent tables/columns/extensions.
- Provide up and down.
- No emojis.
When the card says not legal advice, not certification, not an exam dump, or not a caption engine, that sentence belongs at the top of the output. Deleting it to look more finished is how you inherit risk.
Refuse invented extensions and data UPDATEs
Finish with the compliance pass the prompt already asks for. Quote the banned-word hits. Cut them. Print character counts when the job has a cap. Print word counts when the job has a budget. List gaps as gaps. Five missing facts are more useful than one smooth paragraph.
Tags on the card (postgresql migration schema delta, postgres ddl from brief, schema delta migration sql) are a reminder of the job shape, not an invitation to wander into a neighboring cluster. If you need a different surface, open a different PromptDig card rather than stretching this one.
Fill the card, then run
Replace every bracket. Run on ChatGPT, Claude, or Gemini. Read the ledger first, then the artifact. If the model invents a commit, KPI, DOI, PEL, bid, or logo, discard the run. Tighten Inputs. Run again. Share the filled card that survived, not the first draft that sounded done.