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:

* --.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

$3

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;
`

$3

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 ##

$3

* none

$3

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

$3

* fixed up a test related to patch application

$3

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

$3

* fix patch direction error message

$3

* fix error handling when the connection fails

$3

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

License ##

Mozilla Public License v2

(Ends)