private function _prepareValues(array $valueArrays)
	{
		if(count($valueArrays) === 0)
		{
			throw new \Exception('The value method of the statement must called before!');
		}
		foreach($valueArrays as $valueArray)
		{
			$valueString = '(';
			foreach($valueArray as $value)
			{
				$valueString .= $value->getValue() . ', ';
			}
			$valueString = rtrim($valueString);
			$valueString = rtrim($valueString, ',') . ')';
			$this->values .= $valueString . ', ';
		}
		$this->values = rtrim($this->values);
		$this->values = rtrim($this->values, ',');

		return $this;
	}