Think/Db/Driver.php
public function startTrans()
    {
        $this->initConnect();
        if (!$this->_linkID) {
            return false;
        }
        //数据rollback 支持
        if ($this->transTimes == 0) {
            $this->_linkID->beginTransaction();
        }
        $this->transTimes++;

        return;
    }
public function startTrans()
    {
        $this->initConnect();
        if (!$this->_linkID) {
            return false;
        }
        //数据rollback 支持
        if ($this->transTimes == 0) {
            $this->_linkID->beginTransaction();
        }
        $this->transTimes++;

        return;
    }
启动事务

@return mixed