/**
  * @param \Doctrine\ORM\Query\AST\Node  $AST
  * @param \Doctrine\ORM\Query\SqlWalker $sqlWalker
  */
 public function __construct(AST\Node $AST, $sqlWalker)
 {
     if ($AST instanceof AST\UpdateStatement) {
         $this->_sqlStatements = $sqlWalker->walkUpdateStatement($AST);
     } else {
         if ($AST instanceof AST\DeleteStatement) {
             $this->_sqlStatements = $sqlWalker->walkDeleteStatement($AST);
         }
     }
 }