public function createUpdateCommand($table,$data,$criteria)
	{
		$criteria=$this->checkCriteria($table,$criteria);
		$fields=array();
		$values=array();
		$bindByPosition=isset($criteria->params[0]);
		$i=0;
		foreach($data as $name=>$value)
		{
			if(($column=$table->getColumn($name))!==null)
			{
				if ($table->sequenceName !== null && $column->isPrimaryKey === true) continue;
				if ($column->dbType === 'timestamp') continue;
				if($value instanceof CDbExpression)
				{
					$fields[]=$column->rawName.'='.$value->expression;
					foreach($value->params as $n=>$v)
						$values[$n]=$v;
				}
				elseif($bindByPosition)
				{
					$fields[]=$column->rawName.'=?';
					$values[]=$column->typecast($value);
				}
				else
				{
					$fields[]=$column->rawName.'='.self::PARAM_PREFIX.$i;
					$values[self::PARAM_PREFIX.$i]=$column->typecast($value);
					$i++;
				}
			}
		}
		if($fields===array())
			throw new CDbException(Yii::t('yii','No columns are being updated for table "{table}".',
				array('{table}'=>$table->name)));
		$sql="UPDATE {$table->rawName} SET ".implode(', ',$fields);
		$sql=$this->applyJoin($sql,$criteria->join);
		$sql=$this->applyCondition($sql,$criteria->condition);
		$sql=$this->applyOrder($sql,$criteria->order);
		$sql=$this->applyLimit($sql,$criteria->limit,$criteria->offset);

		$command=$this->getDbConnection()->createCommand($sql);
		$this->bindValues($command,array_merge($values,$criteria->params));

		return $command;
	}