SQL Server data retrieving speed problem

Hi guys,
I 'm building Qt application based on QTextEdit. The app retrieves data from SQL Server database and inserts it into QTextEdit in the form of table. (Later I create pdf or print)
Everything works fine except for the speed.

Problem:
Data retrieving lasts too long. It seems to me that each time I get record from the QSqlQuery object, the app sends query to SQL Server. Shouldn't QSqlQuery object have buffer with returned data set?

Potential solution:
QSqlTableModel + QTableView works much faster, but I really need that data in the QTextEdit object for inserting some other data and printing!

Does anyone know faster way for this?

Example code:

Code:

---

…
//CREATE & EXECUTE QUERY
QSqlQuery queryAlarms;
queryAlarms.exec(“SELECT …”);
//FULFIL TEXT TABLE WITH RECORDS
FulfilTableWithRecords (queryAlarms, cursor, texttableTable, formatCellFormat2);
…
 
void AlarmsEditor::FulfilTableWithRecords (QSqlQuery queryAlarms, QTextCursor cursor, QTextTable* texttableTable, QTextCharFormat formatCellFormat2)
{
    QSqlRecord record;
    QString strAlarmTime;
    QString strAckTime;
    QString strReturnTime;
    QString strTagName;
    double doubleValue;
    QString strLimit;
    QString strKomentar1;
    QString strAckOperatorName;
    QString strKomentar2;
 
    while(queryAlarms.next())
    {
	//INSERT ROW IN THE TABLE
        texttableTable->appendRows(1);
        //GET ONE RECORD
        record = queryAlarms.record();
        //GET FIELDS FROM THE RECORD
        strAlarmTime = record.value(0).toString();   
        strAckTime = record.value(1).toString();
        strReturnTime = record.value(2).toString();
        strTagName = record.value(3).toString();
        doubleValue = record.value(4).toDouble();
        strLimit = record.value(5).toString();
        strKomentar1 = record.value(6).toString();
        strAckOperatorName = record.value(7).toString();
        strKomentar2 = record.value(8).toString();
        //CHANGE TIME FORMAT. "2010-07-27T07:27:27" to "2010-07-27 07:27:27"
        strAlarmTime.replace("T", " ");
        strAckTime.replace("T", " ");
        strReturnTime.replace("T", " ");
        //FULFIL ONE ROW IN THE TABLE
        cursor.insertText(strAlarmTime, formatCellFormat2);
        cursor.movePosition(QTextCursor::NextCell);
        cursor.insertText(strAckTime, formatCellFormat2);
        cursor.movePosition(QTextCursor::NextCell);
        cursor.insertText(strReturnTime, formatCellFormat2);
        cursor.movePosition(QTextCursor::NextCell);
        cursor.insertText(strTagName, formatCellFormat2);
        cursor.movePosition(QTextCursor::NextCell);
        cursor.insertText(tr("%1").arg(doubleValue), formatCellFormat2);
        cursor.movePosition(QTextCursor::NextCell);
        cursor.insertText(strLimit, formatCellFormat2);
        cursor.movePosition(QTextCursor::NextCell);
        cursor.insertText(strKomentar1, formatCellFormat2);
        cursor.movePosition(QTextCursor::NextCell);
        cursor.insertText(strAckOperatorName, formatCellFormat2);
        cursor.movePosition(QTextCursor::NextCell);
        cursor.insertText(strKomentar2, formatCellFormat2);
        cursor.movePosition(QTextCursor::NextRow);
    }
}

---

It seems like there is no problem with SQL Server data retrieving speed. The QTextTable which I use in QTextEdit to show retrieved data is the one that is slow !!!
Does anyone know how to make QTextTable works faster?!?

Have you tried to wrap your update code into:

Code:

---

..
texttableTable->setUpdatesEnabled(false);
while (queryAlarms.next())
{
   ...
}
texttableTable->setUpdatesEnabled(true);

---

HIH

Joh

Thank you Joh,

This is a valuable note for me, but my app still has speed problem. If you have any more suggestions please share with me!

Aleksandar

Hi!

I don't know if it will help, but you could try the following:

1) retrieve the number of rows matching your query directly from mysql. => count ?
2) append this number of rows to your text table at once
3) fill the data.

This way the texttable is only resized once. Maybe that increases the speed?

Joh