protected property

A closure or anonymous function which receives an instance of this class, a collection name and associated meta information, and returns an array defining the schema for an associated model, where the keys are field names, and the values are arrays defining the type information for each field. At a minimum, type arrays must contain a 'type' key. For more information on schema definitions see the $_schema property of the Model class.

This example shows how to implement a schema callback in your database connection configuration that fetches and returns the schema data. It defines an optional MongoDB convention in which the schema for each individual collection is stored in a schemas collection, where each document contains the name of a collection, along with a 'data' key, which contains the schema for that collection.

Connections::add('default', [
 'type' => 'MongoDb',
 'host' => 'localhost',
 'database' => 'app',
 'schema' => function($db, $collection, $meta) {
     $result = $db->connection->schemas->findOne(compact('collection'));
     return $result ? $result['data'] : [];

A complete schema defintion looks like:

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

The types in the schema map to database native type like this:

 id      => MongoDB\BSON\ObjectId
 date    => MongoDB\BSON\UTCDateTime
 regex   => MongoDB\BSON\Regex
 integer => integer
 float   => float
 boolean => boolean
 code    => MongoDB\BSON\Javascript
 binary  => MongoDB\BSON\Binary


	protected $_schema = null;