Zend_Db_Select 问题修复

学习zend framework1.5,我想看看它换个数据库是不是会有问题，于是我把akrabat例子中的脚本改成sqlserver的。
结果 新增编辑删除都报错。
经过一番摸索，找到原因了，Zf1.5 zend/db/select.php生成查询字符串出错了。它把生成的条件全部加到后面，而sqlserver需要修改相应的Sql
Zend\Db\Select.php
问题自己修复如下：
__toString()函数修改如下

/**
     * Converts this object to an SQL SELECT string.
     *
     * @return string This object as a SELECT string.
     */
    public function __toString()
    {
        $sql = array(self::SQL_SELECT);
        foreach (array_keys(self::$_partsInit) as $part) {
            $method = '_render' . ucfirst($part);
            if (method_exists($this, $method)) {
                      if(ucfirst($part)=='Limitoffset')
                      {
                        $tmpstr=implode(' ', array_filter($sql));
                        unset($sql);
                        $sql[] = $this->$method($tmpstr);
                      }
                      else
                        $sql[] = $this->$method();
            }
        }
        return implode(' ', array_filter($sql));
    }

_renderLimitoffset函数修改：

/**
     * Render LIMIT OFFSET clause
     *
     * @return string|null
     */
    protected function _renderLimitoffset($sqlstr = null)
    {
        $count = 0;
        $offset = 0;
               
        if (!empty($this->_parts[self::LIMIT_OFFSET])) {
            $offset = (int) $this->_parts[self::LIMIT_OFFSET];
            // This should reduce to the max integer PHP can support
            $count = intval(9223372036854775807);
        }

        if (!empty($this->_parts[self::LIMIT_COUNT])) {
            $count = (int) $this->_parts[self::LIMIT_COUNT];
        }

        /*
         * Add limits clause
         */
        if ($count > 0) {
           return trim($this->_adapter->limit($sqlstr , $count, $offset));
        }
               
        return $sqlstr;
    }

Zend怎么改我就管不着了，这样反证解决了我的问题。