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copied!<p>You can get creative using a addref/release like approach. Just create a few functions and an integer variable in your shared datamodule to do the magic, and be sure to call them..partial code follows:</p> <pre><code>TDMShared = class(tDataModule) private fQueryCount : integer; // set to 0 in constructor public function GetQuery : tDataset; procedure CloseQuery; end; function TDMShared.GetQuery : tDataset; begin inc(fQueryCount); if fQueryCount = 1 then SharedDatsetQry.open; Result := shareddatasetqry; // your shared dataset here end; procedure TDMShared.CloseQuery; begin dec(fQueryCount); if fQueryCount <= 0 then shareddatasetqry.close; // close only when no refs left. end; </code></pre> <p><strong>EDIT:</strong> To do this with multiple queries, you need a container to hold the query references, and a way to manipulate them. a tList works well for this. You will need to make appropriate changes for your TDataset descendant, as well as create a FreeAndNil function if you are using an older version of Delphi. The concept I used for this was to maintain a list of all queries you request and manipulate them by the handle which is in effect the index of the query in the list. The method FreeUnusedQueries is there to free any objects which no longer have a reference...this can also be done as part of the close query method, but I separated it to handle the cases where a specific query would need to be reopened by another module. </p> <pre><code> Procedure TDMShared.DataModuleCreate(Sender:tObject); begin dsList := tList.create; end; Function TDMShared.CreateQuery(aSql:String):integer; var ds : tAdoDataset; begin // create your dataset here, for this example using TADODataset ds := tAdoDataset.create(nil); // self managed ds.connection := database; ds.commandtext := aSql; ds.tag := 0; Result := dsList.add(ds); end; function TDMShared.GetQuery( handle : integer ) : tDataset; begin result := nil; if handle > dsList.count-1 then exit; if dsList.Items[ handle ] = nil then exit; // handle already closed result := tAdoDataset( dsList.items[ handle ]); Inc(Result.tag); if Result.Tag = 1 then Result.Open; end; procedure TDMShared.CloseQuery( handle : integer ); var ds : tAdoDataset; begin if handle > dsLIst.count-1 then exit; ds := tAdoDataset( dsList.items[ handle ]); dec(ds.Tag); if ds.Tag <= 0 then ds.close; end; procedure TDMShared.FreeUnusedQueries; var ds : tAdoDataset; ix : integer; begin for ix := 0 to dsList.Count - 1 do begin ds := tAdoDataset(dsLIst.Items[ ix ]); if ds.tag <= 0 then FreeAndNil(dsList.Items[ix]); end; end; procedure TDMShared.DataModuleDestroy(Sender: TObject); var ix : integer; begin for ix := 0 to dsList.count-1 do begin if dsLIst.Items[ix] <> nil then FreeAndNil(dsLIst.Items[ix]); end; dsList.free; end; </code></pre>

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