From the looks of it, you have to re-create the models when you change these settings.

So my final solution is:

class SqlRelationalDelegate : public QSqlRelationalDelegate { Q_OBJECT public: StorageSqlRelationalDelegate(QObject* parent = nullptr) : QSqlRelationalDelegate(parent) {} QWidget* createEditor(QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index) const override { editor = QSqlRelationalDelegate::createEditor(parent, option, index); return editor; } void destroyEditor(QWidget* editor, const QModelIndex& index) const override { QSqlRelationalDelegate::destroyEditor(editor, index); this->editor = nullptr; } QWidget* getEditor() const { return editor; } private: mutable QWidget* editor = nullptr; }; ... class TableView : public QTableView { Q_OBJECT public: StorageTableView(QWidget* parent = nullptr) {} void openPersistentEditor(const QModelIndex &index) { QTableView::openPersistentEditor(index); emit persistentEditorOpened(index); } signals: void persistentEditorOpened(const QModelIndex &index); }; ... connect(view, &TableView::persistentEditorOpened, [view] (const QModelIndex& index) { auto model = view->model(); auto delegate = qobject_cast<SqlRelationalDelegate*>(view->itemDelegate(index)); if (!delegate) qFatal("Delegate cast error"); delegate->setModelData(delegate->getEditor(), model, index); });

@VRonin
Ah. I believe the user described the interface he gets currently (with his QTableView). Whether he likes it or not is a different matter.

Then his question was: how does he get a notification when, having created a new row, it is actually sent to the database for INSERT, given that there is no signal for this in his case ("editStrategy is OnFieldChange").

My overriding QSqlTableModel::insertRowIntoTable() is how to achieve that. So yours is to do with the interface for adding a new row, right? Whether he would benefit/prefer to change over to that to I cannot say :)

I don't understand this question.

How do you think about information from Cppcheck's forum and issue tracker? Do you care for software aspects which can be discussed there?

What further software evolution ?

You might occasionally find SQL data models more promising, don't you?

To use it as a model for QTableView with PostgreSQL 9.1 on PySide2, I subclass QSqlTableModel and rewrite the function insertRowIntoTable (assuming the primary key of serial type is the first field of the record) :

def insertRowIntoTable(self, values): if QSqlTableModel.insertRowIntoTable(self, values): # returns the value of the primary key "autovalue" (serial) only when the record is added in database rs = QSqlQuery() rs.exec_("SELECT CURRVAL (pg_get_serial_sequence('public." + self.tableName() + "','"+ self.primaryKey().field(0).name() +"'))") if rs.next(): ID = rs.value(0) # without this line the row displayed in the QTableView immediately after insertion cannot be updated self.setData (self.index(self.rowCount()-1,0), ID) # without this line the created row appears blank in the QTableView values.remove(0) return True return False

@SGaist Ok that makes sense. Thank you

@mranger90 said in sqlite commands not working in qt:

Apparently you can not directly access an SQLite database from a resource. There are some discussions about this, but I cant find the links right now.

Indeed, Qt resources are compiled into the executable (or standalone binary file) which is read-only. Good catch! :-)

I did this:

ui->comboBox->clear(); ((QSqlTableModel*)ui->comboBox->model())->select();

And it's working!

@spektro37
Well its used with all QWidgets so would make sense.

Its something to be aware of when creating GUI and also the little note that
any QWidget that are not given a owner/parent, will become a window.
That can be surprised when coming from other frameworks.

Say you make a new label

QLabel *lab= new QLabel();

Since its given no parent, it will become a window.

That was pretty surprising to me first time as i wanted to insert it into the main window.

So its good to know about.

I've uncovered the same issue with QSqlQueryModel using the Windows QODBC database engine connected to MS SQL Server, and have been do some digging. Hopefully this will help others experiencing this issue.

There are a couple of different things happening here.

First, QSqlQueryModel does not support forward only queries. If you try to use a forward only query, QSqlQueryModel::lastError() will return "Forward-only queries cannot be used in a data model".

That seems clear, but does not explain the situation when the forward only is left in its default false state or explicitly set in code. During my exploration of the issue, I would notice that even though I called QSqlQuery::setForwardOnly(false), a call to QSqlQuery::isForwardOnly() made after the query was executed would show forward only set to true, something I did not understand.

Then I read the Qt documentation for setForwardOnly:

Setting forward only to false is a suggestion to the database engine, which has the final say on whether a result set is forward only or scrollable. isForwardOnly() will always return the correct status of the result set.

The database engine has the final say whether or not forward only is used!

Why was the database engine setting forward only? Qt's SQL Database Drivers documentation gives part of the answer if you know what you are looking at.

ODBC Stored Procedure Support

With Microsoft SQL Server the result set returned by a stored procedure that uses the return statement, or returns multiple result sets, will be accessible only if you set the query's forward only mode to forward using QSqlQuery::setForwardOnly().

By observation, the QODBC database engine (in Qt 5.8) recognizes when more than one return set has resulted from the query, so it is automatically setting forward only to true.

How are multiple result sets generated? I've uncovered a few ways.

A query that has multiple select statements (e.g. select * from table1; select * from table2). Stored Procedures In particular, MS SQL Server documentation has this to say:

SQL Server stored procedures have four mechanisms used to return data:

Each SELECT statement in the procedure generates a result set. The procedure can return data through output parameters. A cursor output parameter can pass back a Transact-SQL server cursor. The procedure can have an integer return code.

The first item in Microsoft's list was the key for me. When NOCOUNT is OFF, Even a simple internal variable assignment using a select (e.g. select @user = 'fred') generated a return set. Setting NOCOUNT to ON stops this behavior. From Microsoft's documentation on NOCOUNT

SET NOCOUNT ON prevents the sending of DONE_IN_PROC messages to the client for each statement in a stored procedure. For stored procedures that contain several statements that do not return much actual data, or for procedures that contain Transact-SQL loops, setting SET NOCOUNT to ON can provide a significant performance boost, because network traffic is greatly reduced.

The Solution for me turned out to be two things:

Add SET NOCOUNT ON to the top of my stored procedure so that only the select statement I cared about was returned Instead of using QSqlQueryModel, manually extract the results from the query and build my own QStandardItemModel.

Awesome! Thank you @VRonin .

Either trigger the submit yourself or fill all fields in the row.

@maurosanjo
Well, I'm all out of ideas, sorry.

That might happen ;)

By the way, no need to modify the title anymore. You can use the topic tool button to mark the thread as solved :)

@SGaist Thank you. I was missing a }.

I don't know if there are any Qt models that support SQL for trees. I think they were all built for tables so you might have to build one yourself.
Have you checked out the Simple Tree Model example? I found it pretty helpful: http://doc.qt.io/qt-5/qtwidgets-itemviews-simpletreemodel-example.html . Also, if you find it easier, you can use a QStandardItemModel instead of a QAbstractItemModel.

@SGaist I don't mind refactoring it, it's not very long. I will definitely look into this. Thanks!

An example of myModel->setData(myCustomValue, Qt::UserRole + 1); ?