Migration Generator
Generate safe database migration scripts in seconds
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Have you ever added one column at six in the evening and spent the rest of the night putting it back? Schema changes look small until they are not. The type is wrong, the default is missing, and nobody wrote the rollback. The Migration Generator writes the change and the reverse step from a description you can read out loud.
Short answer: Migration Generator is for the developer holding a schema change and no rollback plan. Describe what you are adding, renaming or dropping, name the database, and it returns the statements with comments, indexes and constraints already in place.
What is Migration Generator?
The Migration Generator turns a description of a schema change into the statements that make it happen. Say what you are adding, renaming or dropping, choose your database, and the migration comes back written for that dialect. MySQL and PostgreSQL disagree on plenty, so set the Database dropdown first.
Written for your dialect
Pick your engine and the statements arrive in that dialect, down to how a column type is changed.
Keys and indexes included
Add Constraints and Include Indexes are on by default, so foreign keys and lookups are not an afterthought.
Comments you can review
Set Format to Code + Comments and each statement arrives with the reason for it sitting alongside.
How Does Migration Generator Work?
- Describe the change: the table, the columns, the types, and what happens to rows that already exist.
- Pick a model from the selector.
- Set Database, then Output Type to Migration and Format to SQL or Code + Comments.
- Generate, read the statements, then copy them into your own migration file.
Complexity starts on Standard, a fair place to begin. Include Sample Data is off by default, and for a migration it should stay off.
Where It Fits In A Schema Change
The tool sits between the decision and the pull request. You already know what the change is. What you want is a first draft to argue with. Generate it, paste it into a new migration in your framework, rename things to match your project, then send it for review. Ask for the reverse step in the same request, because that is the part everyone skips.
Small Details That Save A Rollback
- Say roughly how many rows the table holds. A change that is instant on a thousand rows can lock ten million.
- Name the exact type you want, length and precision included, instead of leaving it to be guessed.
- Say whether the column can be null, and what existing rows should get.
- Ask for the down path in the same breath as the up path.
Read The Migration Before It Touches Anything
Even a two line change earns a careful read.
ALTER TABLE orders ADD COLUMN refunded_at TIMESTAMP NULL;
CREATE INDEX idx_orders_refunded_at ON orders (refunded_at);| Check | Why it matters |
|---|---|
| Types and lengths | A column set too short truncates data on the way in |
| Nullability and defaults | Adding NOT NULL to a populated table fails without a default |
| Index and key names | A duplicate name stops the migration halfway through |
| The reverse step | A migration you cannot undo is one you cannot roll back |
Copy first, production later Never run a generated migration straight at production. Restore a copy or a recent backup, run it there, then promote it through your normal process. The tool does not connect to any database.
What You Still Have To Do Yourself
It writes SQL, not a plan. It cannot see your row counts, indexes or replication setup, so judgements about lock time and downtime stay with you. It does not know your framework conventions either, so the file name, the class name and the ordering are yours to set.
Schema work is free here, with no account on EizTools and no credit counter, and each tool ships with its own options rather than one shared settings box. Pick a model per generation from the selector and go. When the job is a single query rather than a schema change, the SQL Generator turns the same kind of plain English description into SQL.
Frequently Asked Questions
Does it write for MongoDB too?
Yes. Set Database to MongoDB and you get the collection and index commands rather than SQL. The same rule applies afterwards: run it against a copy first, because nothing on this page touches a database.
Can it write the rollback as well as the change?
Yes, if you ask for it. Say you want the reverse step in the same request and both come back together. Left unasked, most answers give you the forward migration on its own.
Will it handle data as well as structure?
It can write the backfill or update statements alongside the schema change. Describe what existing rows should become. Large backfills still need batching, and that is worth spelling out in the request.
What if my framework uses its own migration files?
Generate the statements, then paste them into the up and down methods of a new file. The tool writes SQL rather than framework scaffolding, so the file itself and its naming stay yours.
A schema change is one of the few things you cannot quietly undo. Describe it properly, read every line the Migration Generator hands back, and run it somewhere safe first.
Sabir Bepari
Founder of EizTools and a passionate AI enthusiast dedicated to building practical, user-friendly AI tools that simplify everyday tasks.
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