Select data from QSqlite in thread

[isan]

I have used the thread to read data from QSqlite database

void RandomWalk::run()
{
    qDebug("Thread id inside run %d", (int)QThread::currentThreadId());

    QSqlQuery  qry(db);
    qry.prepare( "SELECT * FROM  TEST  ");
      if( !qry.exec() )
        qDebug() <<"here"<< qry.lastError();
      else
      {
        qDebug( "Selected!" );

        QSqlRecord rec = qry.record();
       

       for( int r=0; qry.next(); r++ ){
          qDebug() << QString( "Row %1, %2: %3" ).arg( r ).arg( rec.fieldName(0) ).arg( qry.value(0).toString() );

            qDebug() << QString( "Row %1, %2: %3" ).arg( r ).arg( rec.fieldName(1) ).arg( qry.value(1).toString() );

          }
      }
}

I don't use sleep in thread and it starts with : thread->start();
the output like :

"Row 0, Field1: 77"
"Row 0, Field2: 87"
"Row 1, Field1: 77"
"Row 1, Field2: 87"
"Row 2, Field1: 77"
"Row 2, Field2: 87"
"Row 3, Field1: 76"
"Row 3, Field2: 86"
"Row 4, Field1: 77"








"Row 4, Field2: 87"
"Row 5, Field1: 77"
"Row 5, Field2: 87"
"Row 6, Field1: 77"
"Row 6, Field2: 87"
"Row 7, Field1: 77"
"Row 7, Field2: 87"






....

Why is space between output data?Why is not read data continuous?

[SGaist]

Hi,

What do you mean by space ?
What is the expected output ?

[isan]

@SGaist Hi , the space between Rows 4
The output shouldn't continuous? like this:

"Row 0, Field1: 77"
"Row 0, Field2: 87"
"Row 1, Field1: 77"
"Row 1, Field2: 87"
"Row 2, Field1: 77"
"Row 2, Field2: 87"
"Row 3, Field1: 76"
"Row 3, Field2: 86"
"Row 4, Field1: 77"
"Row 4, Field2: 87"
"Row 5, Field1: 77"
"Row 5, Field2: 87"
"Row 6, Field1: 77"
"Row 6, Field2: 87"
"Row 7, Field1: 77"
"Row 7, Field2: 87"
....

[SGaist]

Each time you call qdebug, you get a new line printed on the console.

[jsulm]

@isan Maybe you have an entry in the database containing many newlines at the end?
Use the debugger to see what data you get in each line.
Also, these empty lines could be from another (main for example) thread.

[JonB]

@isan
As the others say, you might have non-printing bytes in the column in the database. For your debug line try something like:

qry.value(0).toString().toLatin1().toHex()

in order to see what is actually in there.