you must know that “tableModel->setTable(TABELLA); “this method does not select data from the table, but fetches its field information.For selecting data from your table, apply “tableModel->select()”.
Try that and wait for seeing results.

Luca wrote:

Hi all,
I need to use a QDataWidgetMapper to show data from an Sql table:

1. tableModel = new QSqlTableModel()
2. tableModel->setTable(TABELLA);
3.  
4. dataWidgetMapper = new QDataWidgetMapper(this);
5. dataWidgetMapper->setModel(tableModel);
6. dataWidgetMapper->addMapping(ui->idEdit, tableModel->fieldIndex("id"));
7. dataWidgetMapper->addMapping(ui->descrizioneEdit, tableModel->fieldIndex("descrizione"));
8. dataWidgetMapper->addMapping(ui->nomeEdit, tableModel->fieldIndex("nome"));
9. dataWidgetMapper->addMapping(ui->menuEdit, tableModel->fieldIndex("menu"));
10. ...
11. ...

This part works fine. Now I’d like to show the “available” menu in a QComboBox (and not in QLineEdit) because there is a vs_menu sql table that contain all the “menu name”.

I tried this:

1. tableModel = new QSqlRelationalTableModel();
2. tableModel->setTable(TABELLA);
3. tableModel->setRelation(3, QSqlRelation("vs_menu", "nome", "nome"));
4. ...
5. ...
6. dataWidgetMapper->addMapping(ui->idEdit, tableModel->fieldIndex("id"));
7. dataWidgetMapper->addMapping(ui->descrizioneEdit, tableModel->fieldIndex("descrizione"));
8. dataWidgetMapper->addMapping(ui->nomeEdit, tableModel->fieldIndex("nome"));
9. dataWidgetMapper->addMapping(ui->menuComboBox, tableModel->fieldIndex("menu"));
10. dataWidgetMapper->setItemDelegate(new QSqlRelationalDelegate(this));

but the combo isn’t populated…

What do I wrong…?

Thanks maxoreli,

I didn’t write all code but I already used tableModel->select() . And I can see data in my widget except for QComboBox.

What about QComboBox’s setModel() and setModelColumn() functions? Maybe you can use QComboBox without QDataWidgetMapper and connect signals from QComboBox to navigate in QDataWidgetMapper.

sidewinder wrote:

What about QComboBox’s setModel() and setModelColumn() functions? Maybe you can use QComboBox without QDataWidgetMapper and connect signals from QComboBox to navigate in QDataWidgetMapper.

There are a lot of possible solution but I’d like to know if it’s possible to use a QDataWidgetMapper in conjunction with QSqlRelationalTableModel to populate a QComboBox and to select the right item in the QComboBox while navigating the table.

So it isn’t possible?

For now I solved populating the combo in the constructor and positioning the right element by hand while navigating.

Now what when I save with:

After addMapping to QComboBox,you should do this:

pate wrote:

After addMapping to QComboBox,you should do this:

1.  QSqlTableModel *relationalModel = tableModel->relationModel(i);
2.    ui->menuComboBox->setModel(relationalModel);
3.    ui->menuComboBox->setModelColumn(relationalModel->fieldIndex("menu");

What is “i” in :

Ok, now I understand what you mean.

I tried this, now the combo get populated but if I navigate the table with:

the combo doesn’t change showed item…

Is it possible to do that or I must do it by hand?

Luca wrote:

pate wrote:

After addMapping to QComboBox,you should do this:

1.  QSqlTableModel *relationalModel = tableModel->relationModel(i);
2.    ui->menuComboBox->setModel(relationalModel);
3.    ui->menuComboBox->setModelColumn(relationalModel->fieldIndex("menu");

What is “i” in :

1. QSqlTableModel *relationalModel = tableModel->relationModel(i);

?

Sorry！It’s the index of the field “menu”.
Here it should be