Database migration tool

This is used to keep track of database structure, content etc, and update it when need be via deploys.

A table by default called db_versions will be created, containing a single integer.

Scripts will be placed by default in process.cwd()/dbmigration/<version>.js

Each migration script will be ran, and the db_version increased, until no more migration scripts exists.

Installation

npm i larvitdbmigration-pg

Usage

Application startup script

In your application startup script, do something like this:

const DbMigration = require('larvitdbmigration-pg');
const Db = require('larvitdb-pg');
const dbDriver = new Db({
	user: 'foo',
	password: 'bar',
});
const dbMigration = new DbMigration({
	dbDriver,
	tableName: 'db_version', // Optional - defaults to 'db_version'
	migrationScriptPath: './dbmigration', // Optional, defaults to './dbmigration'
	log // Optional, will use log.silly(), log.debug(), log.verbose(), log.info(), log.warn() and log.error() if given.
});

dbMigration.run().then(() => {
	console.log('Database migrated to latest version');
}).catch(err => {
	throw err;
});

Example migration scripts

Lets say the current database have a table like this:

CREATE TABLE bloj (nisse serial);

And in the next deploy we’d like to change the column name "nisse" to "hasse". For this you can do one of two methods:

Javascript

Create the file process.cwd()/migrationScriptPath/1.js with this content:

migrationScriptPath/1.js

'use strict';

// Always make the function async (or return a promise, they are equal)
exports = module.exports = async function (options) {
	const { db } = options;

	await db.query('ALTER TABLE bloj RENAME COLUMN nisse TO hasse;');
};

SQL

IMPORTANT! SQL files will be ignored if a .js file exists.

Create the file process.cwd()/migrationScriptPath/1.sql with this content:

migrationScriptPath/1.sql

ALTER TABLE bloj RENAME COLUMN nisse TO hasse;

Summary

Tadaaa! Now this gets done once and the version will be bumped to 1. If you then create a script named "2.js" or "2.sql" you might guess what happends. :)

Version history

v0.2.0

• Updated larvitdb-pg and the requirements of the database layer

v0.1.3

• Fixed bug with multiple concurrent migrations hangs