src/Model.php
public function getPrimaryKeyValue()
    {
        $primaryKey = $this->getPrimaryKey();
        if (isset($this->$primaryKey)) {
            return $this->$primaryKey;
        } else {
            return null;
        }
    }
public function getPrimaryKeyValue()
    {
        $primaryKey = $this->getPrimaryKey();
        if (isset($this->$primaryKey)) {
            return $this->$primaryKey;
        } else {
            return null;
        }
    }
public function getPrimaryKeyValue ( ) { $ primaryKey = $ this -> getPrimaryKey ( ) ; if ( isset ( $ this -> $ primaryKey ) ) { return $ this -> $ primaryKey ; } else { return null ; } }
Returns the value of the primary key

@return null
Returns the value of the primary key