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POHow to solve a closed dataset error when running an update query in Delphi 7?
 

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  1. POHow to solve a closed dataset error when running an update query in Delphi 7?
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    <p>I keep getting an error in Delphi 7 with my application that uses the Microsoft Jet engine and a Microsoft Access (*.mdb) database. I am making the connection via a TADOQuery component. The error says 'Cannot perform this operation on a closed dataset' and happens only in one event handler when trying to execute an UPDATE query:</p> <pre><code>frmHome.adoqryMain.SQL.Text := 'UPDATE Predictions SET Complete = True WHERE UID = "'+sUID+'"'; </code></pre> <p>The event handler's code is as follows:</p> <pre><code> procedure TfrmAdmin.bmbSubmitClick(Sender: TObject); var sScore, sEID, sPrediction, sUID : String; iRecordCount, x, iPos, iLength, iActual, iPoints, iPointsNew : Integer; rPrediction : Real; begin // Assign values to variables sScore := IntToStr(sedSuthies.Value) + '-' + IntToStr(sedOpponent.Value); iActual := sedSuthies.Value + sedOpponent.Value; sEID := frmHome.arrEID[lstEvents.ItemIndex]; // Update the score for the event in the database frmHome.adoqryMain.Active := False; frmHome.adoqryMain.SQL.Clear; frmHome.adoqryMain.SQL.Text := 'UPDATE Events SET Score = "'+sScore+'",Complete = True WHERE EID = "'+sEID+'" '; frmHome.adoqryMain.ExecSQL; frmHome.adoqryMain.SQL.Text := 'SELECT * FROM Predictions WHERE EID = "'+sEID+'" '; frmHome.adoqryMain.Open; iRecordCount := frmHome.adoqryMain.RecordCount; //Assign points to users for all the predictions for x := 0 to (iRecordCount - 1) do begin sUID := frmHome.adoqryMain.Fields[1].AsString; sPrediction := frmHome.adoqryMain.Fields[4].AsString; iPos := Pos('-',sPrediction) - 1; iLength := Length(sPrediction) - iPos; ShowMessage('1'); if ((sedSuthies.Value &gt;= sedOpponent.Value) AND (StrToFloat(Copy(sPrediction, 1, iPos)) &gt;= StrToFloat(Copy(sPrediction, iPos + 2, iLength + 1)))) OR ((sedSuthies.Value &lt; sedOpponent.Value) AND (StrToFloat(Copy(sPrediction, 1, iPos)) &lt; StrToFloat(Copy(sPrediction, iPos + 2, iLength + 1)))) then begin rPrediction := StrToFloat(Copy(sPrediction, iPos + 2, iLength + 1)) + StrToFloat(Copy(sPrediction, 1, iPos)); if rPrediction &gt;= iActual then rPrediction := rPrediction - iActual else rPrediction := iActual - rPrediction; iPoints := Round(10 * (1 - (rPrediction / iActual))); end else iPoints := 0; ShowMessage('2'); frmHome.adoqryMain.Open; frmHome.adoqryMain.SQL.Text := 'UPDATE Predictions SET Complete = True WHERE UID = "'+sUID+'"'; frmHome.adoqryMain.ExecSQL; ShowMessage('3'); ShowMessage(IntToStr(iPoints)); frmHome.adoqryMain.Next; end; ShowMessage('Score succefully submitted!'); frmHome.UpdateEventLists; end; </code></pre> <p>It's a bit messy at the moment, but irrespective of what the UPDATE query updates, it always gives this error. I've tried opening the TADOQuery, using various methods of running the query (with statement and parameters), etc. Any help would be greatly appreciated.</p> <p>P.S. The ShowMessage functions are there for debugging purposes and will be removed.</p>
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