original_string: public function getPrimaryKey()
      {
          if ($this->_primaryKey === null) {
              $key = (array)$this->getSchema()->primaryKey();
              if (count($key) === 1) {
                  $key = $key[0];
              }
              $this->_primaryKey = $key;
          }
  
          return $this->_primaryKey;
      }
code: public function getPrimaryKey()
      {
          if ($this->_primaryKey === null) {
              $key = (array)$this->getSchema()->primaryKey();
              if (count($key) === 1) {
                  $key = $key[0];
              }
              $this->_primaryKey = $key;
          }
  
          return $this->_primaryKey;
      }
code_tokens: public function getPrimaryKey ( ) { if ( $ this -> _primaryKey === null ) { $ key = ( array ) $ this -> getSchema ( ) -> primaryKey ( ) ; if ( count ( $ key ) === 1 ) { $ key = $ key [ 0 ] ; } $ this -> _primaryKey = $ key ; } return $ this -> _primaryKey ; }
docstring: Returns the primary key field name.
  
  @return string|array
docstring_tokens: Returns the primary key field name .