Migrations Plugin for CakePHP

Version 2.1 for cake 2.x

This migrations plugin enables developers to quickly and easily manage and migrate between database schema versions.

As an application is developed, changes to the database may be required, and managing that in teams can get extremely difficult. Migrations enables you to share and co-ordinate database changes in an iterative manner, removing the complexity of handling these changes. This is not a backup tool, however you can make use of callbacks if you want to backup data or execute extra queries. We highly recommend not to run Migrations in a production environment directly without doing a backup and running it first in a staging environment.

Installing

Usage

Unzip or clone this plugin into your app/Plugin/Migrations folder or the shared plugins folder for your CakePHP installation.
Add the plugin to your app/Config/bootstrap.php using CakePlugin::load('Migrations')
Run Console/cake Migrations.migration run all -p Migrations to initialized the schema_migrations table

Generating your first migration

The first step to adding migrations to an existing database is to import the database's structure into a format the migrations can work with. Namely a migration file. To create the first migration file run the following command:

cake Migrations.migration generate

Answer the questions asked, and it will generate a new file containing a database structure snapshot using the internal migration's plugin syntax. If you want import all tables regardless if it has a model or not you can use -f (force) parameter while running the command:

cake Migrations.migration generate -f

Running migrations

After generating or being supplied a set of migrations, you can process them to change the state of your database.

This is the crux of the migrations plugin, allowing migration of schemas up and down the migration chain, offering flexibility and easy management of your schema and data states.

Runing all pending migrations

To get all pending changes into your database run:

cake Migrations.migration run all

Reseting your database

cake Migrations.migration run reset

Downgrade to previous version

cake Migrations.migration run down

Upgrade to next version

cake Migrations.migration run up

Running migrations for plugins

cake Migrations.migration run all --plugin Users

Getting the status of available/applied Migrations

cake Migrations.migration status

Migration shell return codes

0 = Success 1 = No migrations available 2 = Not a valid migration version

Auto migration files

Once you have Generated your first Migration you will probably do more changes to your database. To simplify the generation of new migration you can do Schema Diffs. To this, you need to follow the steps:

Generate your first Migration (if haven't generated yet)
Generate a schema file with cake schema generate
Do changes to your database using your favorite tool
Generate a new migration file doing cake Migrations.migration generate

Manually creating migration files

If you prefer full control over your changes, or do not want to mess with sql at all you have the option to manually create your migration files. First create a blank migration doing:

cake Migrations.migration generate

And skip the databse to schema comparison if asked. Then open the newly created file under app/Config/Migrations. The file must be filled using the migration directives as follows:

Create Table

Create table is used for the creation of new tables in your database. Note that migrations will generate errors if the specified table already exists in the database. Directives exist (Drop, Rename) to deal with existing tables before proceeding with table creation.

Example:

'create_table' => array(
	'categories' => array(
		'id' => array(
			'type'    =>'string',
			'null'    => false,
			'default' => NULL,
			'length'  => 36,
			'key'     => 'primary'),
		'name' => array(
			'type'    =>'string',
			'null'    => false,
			'default' => NULL),
		'indexes' => array(
			'PRIMARY' => array(
				'column' => 'id',
				'unique' => 1)
		)
	),
	'emails' => array(
		'id' => array(
			'type'    => 'string',
			'length ' => 36,
			'null'    => false,
			'key'     => 'primary'),
		'data' => array(
			'type'    => 'text',
			'null'    => false,
			'default' => NULL),
		'sent' => array(
			'type'    => 'boolean',
			'null'    => false,
			'default' => '0'),
		'error' => array(
			'type'    => 'text',
			'default' => NULL),
		'created' => array(
			'type' => 'datetime'),
		'modified' => array(
			'type' => 'datetime'),
		'indexes' => array(
			'PRIMARY' => array(
				'column' => 'id',
				'unique' => 1)
		)
	)
);

Drop Table

Drop table is used for removing tables from the schema. Directives exist Create, Rename to handle other table based migration operations.

'drop_table' => array(
	'categories',
	'emails'
)

Rename Table

Changes the name of a table in the database. Directives exist (Create, Drop) to handle creation and deletion of tables.

'rename_table' => array(
	'categories' => 'groups',
	'emails' => 'email_addresses'
)

Create Field

Create Field is used to add fields to an existing table in the schema. Note that migrations will generate errors if the specified field already exists in the table. Directives exist (Drop, Rename, Alter) to deal with existing fields before proceeding with field addition.

'create_field' => array(
	'categories' => array(
		'created' => array(
			'type' => 'datetime'),
		'modified' => array(
			'type' => 'datetime')
	)
)

Drop Field

Drop field is used for removing fields from existing tables in the schema. Directives exist (Create, Rename, Alter) to handle other field based migration operations.

'drop_field' => array(
	'categories' => array(
		'created',
		'modified'),
	'emails' => array(
		'error')
)

Alter Field

Changes the field properties in an existing table. Note that partial table specifications are passed, which is a subset of a full array of Table data. These are the fields that are to be modified as part of the operation. If you wish to leave some fields untouched, simply exclude them from the Table spec for the alter operation. Directives exist (Create, Drop, Rename) to handle other field operations.

'alter_field' => array(
	'categories' => array(
		'length' => 11
	)
)

Rename Field

Changes the name of a field on a specified table in the database. Directives exist (Create, Drop, Alter) to handle creation and deletion of fields.

'rename_field' => array(
	'categories' => array(
		'name' => 'title'
	),
	'emails' => array(
		'error' => 'error_code',
		'modified' => 'updated'
	),
)

Alter Index

In order to add a new index to an existing field, you need to drop the field and create it again passing the index definition in an array.

'drop_field' => array(
	'posts' => array('title')
),
'create_field' => array(
	'posts' => array(
		'title' => array('type' => 'string', 'length' => 255, 'null' => false),
		'indexes' => array('UNIQUE_TITLE' => array('column' => 'title', 'unique' => true))
	)
)

Likewise, if you want to drop an index then you need to drop the field including the indexes you want to drop, then you create the field again.

'drop_field' => array(
	'posts' => array('title', 'indexes' => array('UNIQUE_TITLE'))
),
'create_field' => array(
	'posts' => array(
		'title' => array('type' => 'string', 'null' => true, 'length' => 255)
	)
)

Callbacks

You can make use of callbacks in order to execute extra operations, for example, to fill tables with predefined data, you can even use the shell to ask the user for data that is going to be inserted.

Example 1: Create table statuses and fill it with some default data

public $migration = array(
	'up' => array(
		'create_table' => array(
			'statuses' => array(
				'id' => array(
					'type' => 'string',
					'length' => 36,
					'null' => false,
					'key' => 'primary'),
				'name' => array(
					'type' => 'text',
					'null' => false,
					'default' => NULL),
			)
		)
	),
	'down' => array(
		'drop_table' => array('statuses')
	),
);

public function after($direction) {
	$Status = ClassRegistry::init('Status');
	if ($direction == 'up') { //add 2 records to statues table
		$data['Status'][0]['id'] = '59a6a2c0-2368-11e2-81c1-0800200c9a66';
		$data['Status'][0]['name'] = 'Published';
		$data['Status'][1]['id'] = '59a6a2c1-2368-11e2-81c1-0800200c9a67';
		$data['Status'][1]['name'] = 'Unpublished';
		$Status->create();
		if ($Status->saveAll($data)){
			echo "Statues table has been initialized";
		}
	} else if ($direction == 'down') {
		//do more work here
	}
}

Example 2: Prompt the user to insert data

public $migration = array(
	'up' => array(
		'create_table' => array(
			'statuses' => array(
				'id' => array(
					'type' => 'string',
					'length' => 36,
					'null' => false,
					'key' => 'primary'),
				'name' => array(
					'type' => 'text',
					'null' => false,
					'default' => NULL),
			)
		)
	),
	'down' => array(
		'drop_table' => array('statuses')
	),
);

public function after($direction) {
	$Status = ClassRegistry::init('Status');
	if ($direction == 'up') {
		$this->callback->out('Please enter a default status below:');
		$data['Status']['name'] = $this->callback->in('What is the name of the default status?');
		$Status->create(); 
		if ($Status->save($data)){
			echo "Statues table has been initialized";
		}
	} else if ($direction == 'down') {
		//do more work here
	}
}

Requirements

PHP version: PHP 5.2+
CakePHP version: 2.1

Support

For support and feature request, please visit the Migrations Plugin Support Site.

For more information about our Professional CakePHP Services please visit the Cake Development Corporation website.

Branch strategy

The master branch holds the STABLE latest version of the plugin. Develop branch is UNSTABLE and used to test new features before releasing them.

Previous maintenance versions are named after the CakePHP compatible version, for example, branch 1.3 is the maintenance version compatible with CakePHP 1.3. All versions are updated with security patches.

Contributing to this Plugin

Please feel free to contribute to the plugin with new issues, requests, unit tests and code fixes or new features. If you want to contribute some code, create a feature branch from develop, and send us your pull request. Unit tests for new features and issues detected are mandatory to keep quality high.

License

Licensed under The MIT License
Redistributions of files must retain the above copyright notice.

Copyright

Copyright 2009-2012
Cake Development Corporation
1785 E. Sahara Avenue, Suite 490-423
Las Vegas, Nevada 89104
http://cakedc.com

worthy/migrations