The purpose of schema files is to allow you to manage your model definitions directly from a yaml file rather then editing php code. The yaml schema file is parsed and used to generate all your model definitions/classes.
Schema files support all the normal things you would write with manual php code. Component to connection binding, relationships, attributes, templates/behaviors, indexes, etc.
Below is an example schema file for generating a set of models.
You will notice in this schema file it is not always necessary to specify the local and foreign parameters on a relationship. If the foreign columns follow the naming patterns, Doctrine can successfully guess each of them.
This is the directory structure that would be generated at /path/to/generate/models. The base classes contain the actual definitions for the model, and the top level models extend the base and they are only written the first time so you are able to modify them without your additions being overwritten.
It isn't necessary to define both sides of a relationship in the schema.yml file as doctrine will attempt to autocomplete the relationships for you. If you choose to define only one side of the relationship, there are two yaml options you can pass to help doctrine decide how to complete the opposite end of the relationship. For example.
schema.yml
<code type="yml">
---
Table1:
tableName: table_1
relations:
Table2Alias:
class: Table2
local: foreign_key
type: one
foreignAlias: Table1Alias
foreignType: one
columns:
column_1: { type: string, length: 128 }
foreign_key: { type: integer, length: 4 }
Table2:
tableName: table_2
columns:
column_1: { type: string, length: 128 }
foreign_key: { type: integer, length: 4 }
</code>
This schema will define a 1-1 relationship between Table1 and Table2. You'll notice there are two new yaml entries, foreignAlias, and foreignType. ForeignAlias will define the as Alias portion of the opposite relationship, and similarily foreignType defines the reverse relationship of the opposite relationship. Defining foreignType is only necessary when you want a one-to-one relationship, but do not want to define both ends of the relationship manually. The above schema produces the following classes.
<code type="php">
/**
* This class has been auto-generated by the Doctrine ORM Framework
*/
class Table1 extends Doctrine_Record
{
public function setTableDefinition()
{
$this->setTableName('table_1');
$this->hasColumn('column_1', 'string', 128);
$this->hasColumn('foreign_key', 'integer', 4);
}
public function setUp()
{
$this->hasOne('Table2 as Table2Alias', array('local' => 'foreign_key',
'foreign' => 'id',
'onDelete' => 'CASCADE'));
}
}
/**
* This class has been auto-generated by the Doctrine ORM Framework
*/
class Table2 extends Doctrine_Record
{
public function setTableDefinition()
{
$this->setTableName('table_2');
$this->hasColumn('column_1', 'string', 128);
$this->hasColumn('foreign_key', 'integer', 4);
}
public function setUp()
{
$this->hasOne('Table1 as Table1Alias', array('local' => 'id',
'foreign' => 'foreign_key'));
}
}
</code>
As you can see doctrine fully completes the relationship for both classes. You can also use this shorter format for m-to-m relationships. Using the same User and Groups models defined previously, we create a simplified schema.yml. Whereas in the one-to-many and one-to-one the foreignAlias isn't a required field. If you choose to create many-to-many relationships using the short yaml syntax, the foreignAlias is required for proper generation.