Too long to load data from Sql Server

Duy Khang

This post is deleted!

jsulm

@Duy-Khang Please provide more information:

Is the SQL server running on another machine?
How long does it take if you execute same query directly using command line SQL client?
How many rows do you have in that table?

Duy Khang

@jsulm SQL Server is on my machine
it's has 11 rows and if i user command line SQL client then so fast to execute

Duy Khang

This post is deleted!

jsulm

@Duy-Khang said in Too long to load data from Sql Server:

do u have facebook account ?
i'll send you video to watch.

I consider such posts to be spam...

Duy Khang

@jsulm i'm very sorry about that, please help me ! i was stucked for 2 days for its

jsulm

@Duy-Khang said in Too long to load data from Sql Server:

i'm very sorry about that

OK, no problem.

Try to do it like shown here: https://doc.qt.io/qt-5/qsqlquerymodel.html (without QSqlQuery)

modal = new QSqlQueryModel();
modal->setQuery("SELECT name, salary FROM employee");
ui->tableView->setModel(modal);

Does it make a difference?

Duy Khang

@jsulm it's still dont make a difference .

SGaist

Hi,

Which database plugin are you using ?
By the way, there's no need to allocate QSqlQuery on the heap.

Duy Khang

Hi, i'm using SQL Server

Christian Ehrlicher

And how do you know that it's because of the query model?
What Qt version do you use?

Duy Khang

because if i don't use the query model then when click to Xem push button, it's work
and if i use the query model. it takes about 30s to load data from SQL Server.
Version is Qt Creator 4.14.0

Christian Ehrlicher

@Duy-Khang said in Too long to load data from Sql Server:

click to Xem push button, it's work

?

Version is Qt Creator 4.14.0

we don't care which IDE (and it's version) you use - we want to use what Qt version you're using for developing.

Duy Khang

Sorry for my English. i'm using Qt5

Pl45m4

@Christian-Ehrlicher

I assume @Duy-Khang is using 5.15.2 MinGW (the debug output, you can see in the screenshot). So it's probably not some weird buggy behavior

@Duy-Khang have you tried any other query or any other database? Can you print the query result to console?
Set breakpoints to see where it crashes (during the query execution or while filling your tableView/model with data).

Duy Khang

okay, let me try it!

JonB

@Duy-Khang
Can we be clear whether it is specifically because you use QSqlQueryModel that you are seeing slow behaviour?

What is the timing if you just use:

query = new QSqlQuery("SELECT * FROM Lecturer_DATABASE");

?
And what about:

int count = 0;
query = new QSqlQuery("SELECT * FROM Lecturer_DATABASE");
while (query.next()) 
    qDebug() << ++count;

Duy Khang

it's also takes about 10s to execute

JonB

@Duy-Khang
Which one takes 10 seconds? The 1-liner, the 4-liner, both?

Duy Khang

The 1-liner