mysql-patcher

A package/program to help patch MySql databases.

Synopsis

This is the simplest program that can work:

var path = require('path')

var mysql = require('mysql')
var patcher = require('mysql-patcher')

var options = {
  user       : 'user',
  database   : 'db',
  password   : 'password',
  dir        : path.join(__dirname, 'schema'),
  patchKey   : 'schema-patch-level',
  patchLevel : 4,
  metaTable  : 'dbMetadata',
  mysql      : mysql,
}

patcher.patch(options, function(err, res) {
  console.log('err:', err)
  console.log('res:', res)
})

Note: you should require mysql yourself and pass this to .patch() so that we're using the version you want, instead of us depending on mysql ourselves.

.patch(options)

The options are passed straight through to MySql, so you can provide any of the following:

• https://github.com/felixge/node-mysql#connection-options

Discussed below are some of more regular ones, but if not provided they will take the defaults specified on the mysql page (above):

• user : the user for the database (requires permission to create the database if needed)
• password : the password for the database
• host : the host for the database
• port : the port for the database
• socketPath : the socket (instead of host and port)
• database : the database name

Specific options for mysql-patcher:

• dir : string - the directory where the patch files live
• patchLevel : integer - the level to which the database should patched
• metaTable : string - the metaTable name
• patchKey : string - the name of the row in the metaTable which stores the current patch
• createDatabase : true/false - tries to create the database if it doesn't exist (default: false)
• reversePatchAllowed : true/false - allow reverse patching to take place (default: false)

Database Patch Files

All patch files should be named in the following format:

• <name>-<from>-<to>.sql
• e.g. patch-0001-0002.sql

This example is a patch file from level 1 to level 2.

Each database patch file should perform any queries they want first, then the last statement should set your patchKey value (in the metaTable) to the patch specified

Your Initial Patch

Your initial patch shouldn't do much except create the metaTable and set the patchKey row to be 1.

If you don't know what to do, copy and paste these two files for your initial forward and reverse patches:

e.g. Forward patch file : patch-00-01.sql

CREATE TABLE dbMetadata (
  name VARCHAR(255) NOT NULL PRIMARY KEY,
  value VARCHAR(255) NOT NULL
) ENGINE=InnoDB;

INSERT INTO dbMetadata SET name = 'schema-patch-level', value = '1';

e.g. Reverse patch file : patch-01-00.sql

DROP TABLE dbMetadata;

Patches 2 and above

Once your initial patch has worked, each subsequent patch (both forward and reverse) should not try to insert the patch level, but instead update it:

e.g. Forward patch file : patch-01-02.sql

UPDATE dbMetadata SET value = '2' WHERE name = 'schema-patch-level';

e.g. Reverse patch file : patch-02-01.sql

UPDATE dbMetadata SET value = '1' WHERE name = 'schema-patch-level';

License

Mozilla Public License v2

(Ends)