Basic concept of Qt model/view and QTableView

Question

I want to create a software that will browse some database tables and users will be able to edit these tables. Following my reading of this link, I tought that model/view was a good approach for what I need. Look at the following mockup :

Knowing this, I have questions to be sure that I understand the concept. Please, tell my if I am in the good direction :

1. I guess I need to create a model class for each of my tables? (subclassing QAbstractModel). It will look like this :

   class citiesTableModel : public QAbstractItemModel
    {
        Q_OBJECT
    }
   

2. citiesTableModel constructor will fetch data from the table in the database?

   QAbstractItemModel *model = new citiesTableModel(); //model will contain 2 rows, New York and Seattle
   

3. Do I need to subclass QTableView for every different model?

   class citiesTableView : public QTableView{}
   

4. Finnaly, I guess that view.setData and view.setModel need to be reimplemented? setModel will loop over each model rows to build the QTableView, and setData will do proper query to add new data in the model?

Thank you very much.

Answer 1

You can use QSqlTableModel for this.

As the doc says, it can be used quite easy:

QSqlTableModel *model = new QSqlTableModel(parentObject, database);
model->setTable("employee");
model->setEditStrategy(QSqlTableModel::OnManualSubmit);
model->select();
model->setHeaderData(0, Qt::Horizontal, tr("Name"));
model->setHeaderData(1, Qt::Horizontal, tr("Salary"));

QTableView *view = new QTableView;
view->setModel(model);
view->hideColumn(0); // don't show the ID
view->show();

I guess I need to create a model class for each of my tables?

Yes, one model represents one sql table.

citiesTableModel constructor will fetch data from the table in the database?

QSqlTableModel will do it for you:

QSqlTableModel *model = new QSqlTableModel(parentObject, database);
model->setTable("employee");
model->select();

Do I need to subclass QTableView for every different model?

No, you don't. A single QTableview can display any model you set using setModel.

Finnaly, I guess that view.setData and view.setModel need to be reimplemented? setModel will loop over each model rows to build the QTableView, and setData will do proper query to add new data in the model?

Depending on the edit strategy you set using setEditStrategy, the changes will be commited as your are editing table cells, or after you submit them using submitAll.

Also, you may want to take a look at the QDataWidgetMapper. It can map your model data to different widgets and track the changes you are doing editing those widgets.