[SOLVED] QSqlRecord Update

Gundi

Hi everyone. I have a small database with four columns. I have one field that gets updated at a later date so when I run an initial query I can find the record ok. I can also grab the record and add the data required. The problem is it does not actually save it into the database. I tried commit() and that does not work so I believe I am missing something. Anyone see the problem here?

@
QString queryString = "SELECT CommandSent, AckRvcd FROM CommandSequence";
queryString.append(" WHERE CommandSent = '" + reverseCommandHash[returnedCommand] + "'");

         QSqlQuery query(commandDB);
         query.prepare(queryString);
         query.exec&#40;&#41;;


        while(query.next(&#41;)
        {
            if(query.value(1).toString() == "")
            {
                QSqlRecord ackRecord = query.record();

                ackRecord.setValue(1, "True");
                qDebug() << "Field " << ackRecord.value(1);

                /* Tried this but it adds a new row
                query.previous();
                query.prepare("INSERT INTO CommandSequence (AckRvcd)"
                                 "VALUES (:AckRvcd)");
                //Have to create a second query
                query.bindValue(":AckRvcd", "True");
                query.exec(&#41;;*/

            }

}
@

clochydd

Hi,

your second approach will work if you add a new record.
To update a record use:

@
query.prepare(
"UPDATE CommandSequence "
"SET AckRvcd = :AckRvcd"
"WHERE CommandSent = :cSent"
);
query.bindValue(":CommandSent", "test");
query.bindValue(":AckRvcd", "True");
query.exec();

@

Gundi

Thanks and I did try that. The issue really is if I have more that one "test" records in the CommandSent it fills all of them with true, even if previous happened to be false. I just want to select the last one added to the database and not all of them.

clochydd

If you initialise AckRvcd with NULL you may modify your UPDATE like that:

UPDATE CommandSequence SET AckRvcd = :AckRvcd
WHERE CommandSent = :cSent AND AckRvcd IS NULL;

or use AckRvcd IS NOT FALSE...

Gundi

Great thanks I will try that.