Model subclasses can manually define a schema in array notation. The array notation will then be lazily converted to a schema object by the first call to Model::schema().

The schema should only be defined in subclasses for schemaless persistent data sources (e.g. MongoDB), for all other data sources this is done automatically. If you desire a fixed schema for a schemaless data source, the following example shows how you'd define one manually.

For MongoDB specifically, you can also automate schema definition. Please see lithium\data\soure\MondoDb::$_schema for more information.

protected $_schema = [
    '_id'  => ['type' => 'id'],
    'name' => ['type' => 'string', 'default' => 'Moe', 'null' => false],
    'sign' => ['type' => 'string', 'default' => 'bar', 'null' => false],
    'age'  => ['type' => 'integer', 'default' => 0, 'null' => false]
];