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EffianaMigrationBundle

EffianaMigrationBundle extends DBAL (database abstraction layer) and provides the ability for developers to manage and deploy changes in the application database schema programmatically in a consistent, structured way using Migrations and Fixtures classes.

Database structure migrations

Each bundle can have migration files that allow to update database schema.

Migration files should be located in Migrations\Schema\version_number folder. A version number must be an PHP-standardized version number string, but with some limitations. This string must not contain "." and "+" characters as a version parts separator. More info about PHP-standardized version number string can be found in PHP manual.

Each migration class must implement Migration interface and must implement up method. This method receives a current database structure in schema parameter and queries parameter which can be used to add additional queries.

With schema parameter, you can create or update database structure without fear of compatibility between database engines. If you want to execute additional SQL queries before or after applying a schema modification, you can use queries parameter. This parameter represents a MigrationQuery interface. There are several ready to use implementations of this interface:

• SqlMigrationQuery - represents one or more SQL queries
• ParametrizedSqlMigrationQuery - similar to the previous class, but each query can have own parameters.

If you need to create own implementation of ParametrizedMigrationQuery class as a base class for your migration query.

If you have several migration classes within the same version and you need to make sure that they will be executed in a specified order you can use OrderedMigrationInterface interface.

Example of migration file:

Each bundle can have an installation file as well. This migration file replaces running multiple migration files. Install migration class must implement Installation interface and must implement up and getMigrationVersion methods. The getMigrationVersion method must return max migration version number that this installation file replaces.

During an install process (it means that you installs a system from a scratch), if install migration file was found, it will be loaded first and then migration files with versions greater then a version returned by getMigrationVersion method will be loaded.

For example. We have v1_0, v1_1, v1_2, v1_3 migrations. And additionally, we have install migration class. This class returns v1_2 as a migration version. So, during an install process the install migration file will be loaded and then only v1_3 migration file will be loaded. Migrations from v1_0 to v1_2 will not be loaded.

Example of install migration file:

To run migrations, there is effiana:migration:load command. This command collects migration files from bundles, sorts them by version number and applies changes.

This command supports some additional options:

• force - Causes the generated by migrations SQL statements to be physically executed against your database;
• dry-run - Outputs list of migrations without apply them;
• show-queries - Outputs list of database queries for each migration file;
• bundles - A list of bundles to load data from. If option is not set, migrations will be taken from all bundles;
• exclude - A list of bundle names which migrations should be skipped.

Also there is effiana:migration:dump command to help in creation installation files. This command outputs current database structure as a plain sql or as Doctrine\DBAL\Schema\Schema queries.

This command supports some additional options:

• plain-sql - Out schema as plain sql queries
• bundle - Bundle name for which migration wll be generated
• migration-version - Migration version number. This option will set the value returned by getMigrationVersion method of generated installation file.

Good practice for bundle is to have installation file for current version and migration files for migrating from previous versions to current.

Next algorithm may be used for new versions of your bundle:

• Create new migration
• Apply it with effiana:migration:load
• Generate fresh installation file with effiana:migration:dump
• If required - add migration extensions calls to generated installation.

Extensions for database structure migrations

Sometime you cannot use standard Doctrine methods for database structure modification. For example Schema::renameTable does not work because it drops existing table and then creates a new table. To help you to manage such case and allow to add some useful functionality to any migration a extensions mechanism was designed. The following example shows how RenameExtension can be used:

As you can see to use the RenameExtensionAwareInterface and setRenameExtension method. Also there is some additional useful interfaces you can use in your migration class:

• ContainerAwareInterface - provides an access to Symfony dependency container
• DatabasePlatformAwareInterface - allows to write a database type independent migrations
• DbIdentifierNameGenerator class which can be used to generate names of indices, foreign key constraints and others.

Create own extensions for database structure migrations

To create your own extension you need too do the following simple steps:

• Create an extension class in YourBundle/Migration/Extension directory. Using YourBundle/Migration/Extension directory is not mandatory, but highly recommended. For example:

• Create *AwareInterface in the same namespase. It is important that the interface name should be {ExtensionClass}AwareInterface and set method should be set{ExtensionClass}({ExtensionClass} ${extensionName}). For example:

• Register an extension in dependency container. For example

If you need an access to the database platform or the name generator you extension class should implement NameGeneratorAwareInterface appropriately. Also if you need to use other extension in your extension the extension class should just implement *AwareInterface of the extension you need.

Data fixtures

Symfony allows to load data using data fixtures. But these fixtures are run each time when doctrine:fixtures:load command is executed.

To avoid loading the same fixture several time, effiana:migration:data:load command was created. This command guarantees that each data fixture will be loaded only once.

This command supports two types of migration files: main data fixtures and demo data fixtures. During an installation, user can select to load or not demo data.

Data fixtures for this command should be put in Migrations/Data/ORM or in Migrations/Data/Demo/ORM directory.

Fixtures order can be changed with standard Doctrine ordering or dependency functionality. More information about fixture ordering can be found in doctrine data fixtures manual.

Versioned fixtures

There are fixtures which need to be executed time after time. An example is a fixture which uploads countries data. Usually, if you add new countries list, you need to create new data fixture which will upload this data. To avoid this you can use versioned data fixtures.

To make fixture versioned, this fixture must implement VersionedFixtureInterface and getVersion method which returns a version of fixture data.

Example:

In this example, if the fixture was not loaded yet, it will be loaded and version 1.0 will be saved as current loaded version of this fixture.

To have possibility to load this fixture again, the fixture must return a version greater then 1.0, for example 1.0.1 or 1.1. A version number must be an PHP-standardized version number string. More info about PHP-standardized version number string can be found in PHP manual.

If a fixture need to know the last loaded version, it must implement LoadedFixtureVersionAwareInterface and setLoadedVersion method: