Question

I would like to know how I can save a query in memory to display in DBgrid,

my current application is using :

TZConnection > TZquery > DataSource > DBgrid

works fine but the problem here is, after a call ZConnection.disconnect the dbgrid is cleaned

i want to disconnect TZConnection immediately after finish the query because most MySQL databases have an limited numbers of user connected simultaneously.

Answer 1

Use the TDataSetProvider to transfer your Query data into the ClientDataSet. That component does everything for you.

Put the following components on your DataModule, and link them accordingly:

TZQuery <- TDataSetProvider <- TClientDataSet <- TDataSource

TDataSource.DataSet := TClientDataSet;
TCLientDataSet.ProviderName := TDataSetProvider;
TDataSetProvider.DataSet := TZQuery;

After that, just call the TClientDataSet.Open method, and the data are transfered automaticaly into the TClientDataSet. With TClientDataSet.ApplyUpdates, you can push back the data into your database.

I use that technic with firebird (TIBQuery).

Here are some information about ClientDataSets:
A ClientDataSet in Every Database Application
Delphi In Depth: ClientDataSet book
Building Applications With ClientDataSet and InterBase Express