mysql-patcher/README.md

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,
  filePrefix : 'patch',
  metaTable  : 'metadata',
  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)
• filePrefix : string - the patchfile prefix to look for e.g. patch-001-002.sql (default: 'patch')

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 metadata (
  name VARCHAR(255) NOT NULL PRIMARY KEY,
  value VARCHAR(255) NOT NULL
) ENGINE=InnoDB;

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

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

DROP TABLE metadata;

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

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

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

Changelog

Pending

• none

v0.7.0 - 2015-03-16

• added option 'filePrefix' to tighten which files are classed as patch files
• fixed a test related to access for an unknown user

v0.6.1 - 2015-02-02

• fixed up a test related to patch application

v0.6.0 - 2015-02-02

• added ability to create an instance of Patcher which can be controlled more succinctly

v0.5.1 - 2015-01-21

• fix patch direction error message

v0.5.0 - 2015-01-19

• fix error handling when the connection fails

v0.4.0 - 2014-11-14

• added a check between patches to make sure the patch level was incremented properly

License

Mozilla Public License v2

(Ends)