Fix · Supabase and databases

Migration fails (already exists, does not exist, or order problems)

Blocks your work

What you may see

Running my SQL file stops with an error
The table or column already exists, or a relation does not exist

Most likely cause

The file runs against a database that is in a different state than the file expects, or it has a typo, or the files ran in the wrong order.

Check first (about two minutes)

Is this your local test database or your live one? Check before anything else.
Read the error line and number: the problem is usually right there.

The fix prompt

What you type here never leaves your browser. The search runs on this page, and nothing is sent to a server or to an AI.

The exact error or what you see

What you did before it happened

Kept only in this browser, on this device. Keys and passwords are removed before anything is saved.

Prompt language

You are a careful senior engineer who knows Supabase (database, login and file storage) and explains it to people who are not developers. I am not a developer, so explain every step in plain words and tell me exactly which button, menu or command you mean. If you are not sure about something, say so; do not guess.

THE PROBLEM
Migration fails (already exists, does not exist, or order problems)

THE EXACT ERROR OR WHAT I SEE
[paste the exact error here]

WHAT I DID BEFORE IT HAPPENED
[write in a few words what you did before it happened]

MOST LIKELY CAUSE
The file runs against a database that is in a different state than the file expects, or it has a typo, or the files ran in the wrong order.

DO THESE STEPS, IN THIS ORDER
1. Do NOT run anything on the live database yet. Ask me which database the error came from.
2. Reproduce the error on a local or test copy of the database.
3. Fix the file so it can run safely once (use if not exists / if exists where right) and in the right order.
4. Write a rollback file that undoes it. Give me both commands; I will run them myself on the live database after a backup.
Stop and tell me if what you see does not match a step. Do not skip ahead.

CHECK THAT IT WORKED
- On a fresh test copy, the file runs once with no error, and the rollback restores the old state.
Tell me exactly what I should see on the screen when it works.

DO NOT CHANGE
- Do not run migrations on the live database yourself.
- Do not drop tables or columns to make it pass.
- Anything I did not ask about: the design, the text, other pages, other settings or the data.
- Do not delete files, data or branches, do not reset or force-push, and do not rewrite history, unless you first show me exactly what would be lost and I say yes.
- Do not paste, print or ask me to paste a password or secret key into this chat. If one is needed, tell me which settings page of the right service to store it in.

WHEN YOU FINISH
Explain in simple words what you changed (file by file or setting by setting), why you changed it, and how I can undo it.

Paste it into Claude, ChatGPT, Gemini or Cursor, then follow what it says.

After you tried it, did it work?

Steps

Do NOT run anything on the live database yet. Ask me which database the error came from.
Reproduce the error on a local or test copy of the database.
Fix the file so it can run safely once (use if not exists / if exists where right) and in the right order.
Write a rollback file that undoes it. Give me both commands; I will run them myself on the live database after a backup.

Do not do this

Do not run the same SQL twice on live data "to see".
Do not skip a backup before changing the live database.
Do not run migrations on the live database yourself.
Do not drop tables or columns to make it pass.

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