protected function get_item_schema_base() {

		$schema = array(
			'$schema'    => 'http://json-schema.org/draft-04/schema#',
			'title'      => 'students-enrollments',
			'type'       => 'object',
			'properties' => array(
				'post_id'      => array(
					'description' => __( 'The ID of the course/membership.', 'lifterlms' ),
					'type'        => 'integer',
					'context'     => array( 'view', 'edit' ),
					'readonly'    => true,
				),
				'student_id'   => array(
					'description' => __( 'The ID of the student.', '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',
					'context'     => array( 'view', 'edit' ),
				),
				'date_updated' => array(
					'description' => __( 'Date last modified. Format: `Y-m-d H:i:s`', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'view', 'edit' ),
					'readonly'    => true,
				),
				'status'       => array(
					'description' => __( 'The status of the enrollment.', 'lifterlms' ),
					'enum'        => array_keys( llms_get_enrollment_statuses() ),
					'context'     => array( 'view', 'edit' ),
					'type'        => 'string',
				),
				'trigger'      => array(
					'description' => __( 'The enrollment trigger. Default is `any`.', 'lifterlms' ),
					'context'     => array( 'view', 'edit' ),
					'type'        => 'string',
					'default'     => 'any',
					'readonly'    => true,
				),
			),
		);

		$object_type = $this->get_object_type( $schema );

		/**
		 * Filter item schema for the enrollments controller.
		 *
		 * @since 1.0.0-beta.10
		 * @deprecated 1.0.0-beta.27
		 *
		 * @param array $schema Item schema data.
		 */
		return apply_filters_deprecated(
			'llms_rest_enrollments_item_schema',
			array( $schema ),
			'[version]',
			"llms_rest_{$this->get_object_type( $schema )}_item_schema"
		);

	}