Doctrine_manual-1-2-en

Chapter 24: Migrations 336
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Diff Tool
Sometimes you may want to alter your models and be able to automate the migration process
for your changes. In the past you would have to write the migration classes manually for your
changes. Now with the diff tool you can make your changes then generate the migration
classes for the changes.
The diff tool is simple to use. It accepts a "from" and a "to" and they can be one of the
following:
• Path to yaml schema files
• Name of an existing database connection
• Path to an existing set of models
A simple example would be to create two YAML schema files, one named schema1.yml and
another named schema2.yml.
The schema1.yml contains a simple User model:
---
# schema1.yml
User:
columns:
username: string(255)
password: string(255)
Now imagine we modify the above schema and want to add a email_address column:
---
# schema1.yml
User:
columns:
username: string(255)
password: string(255)
email_address: string(255)
Now we can easily generate a migration class which will add the new column to our database:
Doctrine_Core::generateMigrationsFromDiff('/path/to/migration/classes',
'/path/to/schema1.yml', '/path/to/schema2.yml');
This will produce a file at the path /path/to/migration/classes/
1236199329_version1.php
class Version1 extends Doctrine_Migration_Base
{
public function up()
{
$this->addColumn('user', 'email_address', 'string', '255', array
());
}
}
public function down()
{
$this->removeColumn('user', 'email_address');
}
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