如何防止Delphi ADO将整个表加载到内存中？ [英] How to prevent Delphi ADO from loading the entire table into memory?

问题描述

我不是Delphi程序员，但是我有一个旧的Delphi 7应用程序，我需要修复它正在使用ADO。

数据库表（MS Accesss ）包含+1万行，当我设置ADOTable.Active = true时，它开始将整个表加载到RAM中，这需要大量的内存和时间。

我可以阻止ADO加载整个表吗？我试图设置MaxRecords，但没有帮助。

基本上我们所做的只是安装程序启动：

  //连接到数据库
 DataModule.MyADOConnection.Connected：= true; 
 
 DataModule.MeasurementsADOTable.MaxRecords：= 1; 
 
 //打开数据表
 DataModule.MeasurementsADOTable.Active:=true; 
  

设置Active = true后，开始将整个测量加载到RAM中，需要TIME！ p>

我们正在使用MSDASQL.1提供程序。也许它不支持MaxRecords属性？

如何将一些限制查询添加到此数据对象中，只能从测量中加载TOP 1 *？

解决方案

您可以使用TADOQuery来使用sql查询来限制结果集。或者您可以使用TADOTable，并设置 CursorLocation 到服务器端光标，以防止客户端将完整的结果集加载到内存中。

I am not a Delphi programmer, but I I got an old Delphi 7 application that I need to fix and it is using ADO.

The database table (MS Accesss) contains +100,000 rows and when I set the ADOTable.Active=true it starts to load the entire table into RAM and that takes a lot of memory and time.

How can I prevent ADO to load the entire table? I tried to set the MaxRecords but it does not help.

Basically all we do is att program startup:

// Connect to database
DataModule.MyADOConnection.Connected:=true;

DataModule.MeasurementsADOTable.MaxRecords:=1;

// Open datatables
DataModule.MeasurementsADOTable.Active:=true;                  

After setting Active=true it starts to load the entire measurements into RAM and it takes TIME!

We are using the MSDASQL.1 provider. Perhaps it does not support the MaxRecords property?

How do I add some limiting query into this data object to only "load TOP 1 * from Measurements" ?

解决方案

You could use TADOQuery to limit the result set with a sql query. Or you could use TADOTable and set the CursorLocation to a Server side cursor to prevent the client loading the complete resultset in memory.

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