tableView->setModel(model); causes SIGSEGV.

[Christian Ehrlicher]

You should really strip this down to a minimal, compileable example. Simply open a db connection, create and fill a table and set the query to the model. Modify it to your use case until it is crashing or you can see what you are doing wrong.

[JonB]

@snubben
As @Christian-Ehrlicher says.

Given that you say

QSqlQueryModel* model = new QSqlQueryModel(this);
model->setQuery("SELECT field1, field2, prodCount, field3, prod_date  FROM products WHERE 1 = 1 ORDER BY prod_date DESC;");

does work I am not sure where your actual example differs significantly from this. Try it now the way you do it as

QSqlQueryModel* model = new QSqlQueryModel(this);
QSqlQuery query(db);
query.prepare("SELECT field1, field2, prodCount, field3, prod_date  FROM products WHERE 1 = 1 ORDER BY prod_date DESC;");
model->setQuery(query);

I have not included your std::move() not your query.exec();. Only add those in if it does not work as is. See where you get to. If you get that working I'm sure you can then start introducing parameter bindings.

At some point you ought get rid of that QSqlDatabase db class member variable. Per the docs you should be using the static QSqlDatabase QSqlDatabase::database() for that instead. I don't know whether it might be relevant here, probably not but you never know.

[snubben]

It works!

QSqlTableModel* model = new QSqlTableModel(this);

Using this it works. I must read more about QSqlQueryModel and why it didn't work in this situation.
Thank you all!

[JonB]

@snubben said in tableView->setModel(model); causes SIGSEGV.:

Using this it works.

@Christian-Ehrlicher
OP reports that QSqlTableModel works for his QTableView but not QSqlQueryModel. I wonder why? QTV only requires a QAbstractItemModel, QSqlTableModel inherits from QSqlQueryModel, why should the latter not work?

The model for QTV must not be forward-only. Is QSqlQueryModel perhaps automatically forward-only, is that an issue?

UPDATE
Non-issue, see further posts below.

[snubben]

This works too!

QSqlQueryModel* model = new QSqlQueryModel(this);

I feel like a complete moron. I had to check git and in an other function where I get strings for a QComboBox I had

    if (!QSqlDatabase::database().open()) {
        qCritical() << "Database connection failed:" << QSqlDatabase::database().lastError().text();
        //emit errorOccurred(db.lastError().text());
        return result;
    }

which should have of course been

if (!QSqlDatabase::database().isOpen()) {

and this I changed without even reflecting upon it.
A lot I need to learn to properly find the erring location with Qt Creator. Once again, thanks guys & girls!

[JonB]

@snubben said in tableView->setModel(model); causes SIGSEGV.:

This works too!

QSqlQueryModel* model = new QSqlQueryModel(this);

Huh? That is what you started with right at the beginning:

QSqlQueryModel* model = new QSqlQueryModel(this);

That's from your first post. So if you're not saying you had to change from a QSqlQueryModel to a QSqlTableModel per your previous post --- and like I write to @Christian-Ehrlicher I don;t see why you should have to --- then I don't understand what you think you changed to make it work.

[snubben]

@JonB said in tableView->setModel(model); causes SIGSEGV.:

@snubben said in tableView->setModel(model); causes SIGSEGV.:

This works too!

QSqlQueryModel* model = new QSqlQueryModel(this);

Huh? That is what you started with right at the beginning:

QSqlQueryModel* model = new QSqlQueryModel(this);

That's from your first post. So if you're not saying you had to change from a QSqlQueryModel to a QSqlTableModel per your previous post --- and like I write to @Christian-Ehrlicher I don;t see why you should have to --- then I don't understand what you think you changed to make it work.

In the previous post I explained that I erroneously called QSqlDatabase::database().open() twice!

[JonB]

@snubben
OK. Hopefully the moral for you is this is why we (usually) insist on people pasting a complete, minimal example of their code before spending a lot of time on fragments.

[snubben]

@JonB said in tableView->setModel(model); causes SIGSEGV.:

@snubben
OK. Hopefully the moral for you is this is why we (usually) insist on people pasting a complete, minimal example of their code before spending a lot of time on fragments.

OK, I will do that the next time, thanks!

[Pl45m4]

@snubben said in tableView->setModel(model); causes SIGSEGV.:

In the previous post I explained that I erroneously called QSqlDatabase::database().open() twice!

That's why you should use QSqlDatabase::database() and not a DB member... it's less easier to make mistakes there, since database() returns the currently opened connection.

@Pl45m4 said in tableView->setModel(model); causes SIGSEGV.:

Also:

if (!db.isOpen()) {

This looks like you store your db connection as private member in DatabaseHandler.
Don't do that, it might cause undefined behavior. Better use the static QSqlDatabase::database() whenever it's needed.

I said it here :)

@JonB said in tableView->setModel(model); causes SIGSEGV.:

At some point you ought get rid of that QSqlDatabase db class member variable. Per the docs you should be using the static QSqlDatabase QSqlDatabase::database() for that instead. I don't know whether it might be relevant here, probably not but you never know.

And @JonB said it here again :)

[snubben]

Point taken! I will remove it. Thanks!