protected function get_item_schema_base() {

		return array(
			'$schema'    => 'http://json-schema.org/draft-04/schema#',
			'title'      => 'students-progress',
			'type'       => 'object',
			'properties' => array(
				'student_id'   => array(
					'description' => __( 'The ID of the student.', 'lifterlms' ),
					'type'        => 'integer',
					'context'     => array( 'view', 'edit' ),
					'readonly'    => true,
				),
				'post_id'      => array(
					'description' => __( 'The ID of the course/membership.', 'lifterlms' ),
					'type'        => 'integer',
					'context'     => array( 'view', 'edit' ),
					'readonly'    => true,
				),
				'date_created' => array(
					'description' => __( 'Creation date. Format: Y-m-d H:i:s', 'lifterlms' ),
					'type'        => 'string',
					'format'      => 'date-time',
					'context'     => array( 'view', 'edit' ),
					'arg_options' => array(
						'validate_callback' => array( $this, 'validate_date_created' ),
					),
				),
				'date_updated' => array(
					'description' => __( 'Date last modified. Format: Y-m-d H:i:s', 'lifterlms' ),
					'type'        => 'string',
					'format'      => 'date-time',
					'context'     => array( 'view', 'edit' ),
					'readonly'    => true,
				),
				'status'       => array(
					'description' => __( 'The status of the enrollment.', 'lifterlms' ),
					'enum'        => array( 'complete', 'incomplete' ),
					'context'     => array( 'view', 'edit' ),
					'type'        => 'string',
					'required'    => true,
				),
				'progress'     => array(
					'description' => __( 'Student\'s progress as a percentage.', 'lifterlms' ),
					'enum'        => array( 'complete', 'incomplete' ),
					'context'     => array( 'view', 'edit' ),
					'type'        => 'number',
					'readonly'    => true,
				),
			),
		);

	}