postgrator

Postgrator is a SQL migration tool for SQL people

npm install postgrator
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Postgrator

A Node.js SQL migration tool using plain SQL scripts.

Overview

Postgrator is a migration tool using SQL instead of a DSL/library in some other language. It currently supports PostgreSQL, MySQL, and SQL Server.

Usage

Create a folder and stick some SQL scripts in there that change your database in some way. It might look like:

migrations/
  |- 001.do.sql
  |- 001.undo.sql
  |- 002.do.sql
  |- 002.undo.sql
  |- ... and so on

The files must follow the convention [version].[action].sql.

Version must be a number, but you may start and increment the numbers in any way you'd like. If you choose to use a purely sequential numbering scheme instead of something based off a timestamp, you will find it helpful to start with 000s or some large number for file organization purposes.

Action must be either "do" or "undo". Do implements the version, and undo undoes it.

To run your sql migrations with Postgrator, you'll write a Node.js script or add it to your application in some way:

var postgrator = require('postgrator');

postgrator.config.set({
    migrationDirectory: __dirname + '/migrations',  // path to the migrations
    driver: 'pg',                                   // or 'mysql' or 'tedious' or 'mssql' (last 2 both non-native SQL Server drivers)
    host: '127.0.0.1',
    database: 'databasename',
    username: 'username',
    password: 'password'
}); 

postgrator.migrate('002', function (err, migrations) {
    if (err) console.log(err)
    else console.log(migrations)
});

Alternatively, for Postgres you could also do:

var postgrator = require('postgrator');

postgrator.config.set({
    migrationDirectory: __dirname + '/migrations',
    driver: 'pg',
    connectionString: 'tcp://username:password@hosturl/databasename'
}); 

postgrator.migrate('002', function (err, migrations) {
    if (err) console.log(err)
    else console.log(migrations)
});

Helpful Info

When first run against your database, Postgrator will create a table called schemaversion. Postgrator relies on this table to track what version the database is at.

Postgrator automatically determines whether it needs to go "up" or "down", and will update the schemaversion table accordingly. If the database is already at the version specified to migrate to, Postgrator does nothing.

If a migration fails, Postgrator will stop running any further migrations. It is up to you to migrate back down to the version you started at if you are running several migration scripts. Because of this, keep in mind how you write your SQL - You may (or may not) want to write your SQL defensively (ie, check for pre-existing objects before you create new ones).

I'm not really sure what happens if a migration takes a really long time to run. Let me know if you run into any weird behavior.

Version 0.2.x Notes

  • Updated database drivers to latest versions
  • pg module swapped out for javascript only pg.js version (cli tool now possible)
  • mssql now used instead of tedious (mssql is just a nice wrapper around tedious)
  • All migrations are run under a single connection instead of creating a new connection for each query
  • config.set accepts a connectionString for Postgres only as an alternative to host/database/username/password

Installation

npm install postgrator

License

MIT

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