模式更改后，Firedac查询字段列表未更新 [英] Firedac Query Field list not updated after Schema change

问题描述

我正在用SQL创建一个临时表，然后向其中添加一个新字段。似乎Firedac正在缓存此临时表的字段列表。

以下代码为我提供了 FDQuery5：找不到字段'Available'。

I am creating a temp table in SQL and then adding a new field to it. It seems Firedac is caching the field list for this temp table.
The following code gives me "FDQuery5: Field 'Available' not found."

  FDQuery5.Connection := FDConnection1;
  FDConnection1.ExecSQL('Select StockNo into #Temp from Stock');
  FDQuery5.SQL.Text := 'Select * From #Temp';
  FDQuery5.open;
  FDConnection1.ExecSQL('Alter Table #Temp add Available Char(1)');
  FDQuery5.Close;
  FDQuery5.open;
  ShowMessage(FDQuery5.FieldByName('Available').AsString);

使用带有Firedac的XE5。
我尝试了Connection.RefreshMetadataCache，并从FetchOptions.Cache中删除了fiMeta。

using XE5 with Firedac. I have tried Connection.RefreshMetadataCache and I have removed fiMeta from FetchOptions.Cache.

如果修改SQL，我可以让Firedac识别新字段。文本。这是不可取的，因为我的应用程序需要在很多地方进行修改。

I can get Firedac to recognise the new field if I modify the SQL.Text. This is undesirable as my application will need modifying in quite a few places.

推荐答案

在调用FDQuery5之后，查询仍处于准备状态。 。这意味着，它还缓存结果集结构。要准备查询，请用FDQuery5.Disconnect替换FDQuery5.Close。

The query remains prepared after you call FDQuery5.Close. That means, it caches also result set structure. To prepare the query replace FDQuery5.Close with FDQuery5.Disconnect.

这篇关于模式更改后，Firedac查询字段列表未更新的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！