/** * Gets the name of the single id field. Note that this only works on * entity classes that have a single-field pk. * * @return string * @throws MappingException If the class has a composite primary key. */ public function getSingleIdentifierFieldName() { if ($this->isIdentifierComposite) { throw MappingException::singleIdNotAllowedOnCompositePrimaryKey($this->name); } return $this->identifier[0]; }