QTableView field (related to other db table) does not get refreshed

[Panoss]

The articlesTable (a QTableView) displays data from db table 'articles'.
The field 'positions' is related to table 'positions'.
The code:

// Create the data model for articles:
 model = new QSqlRelationalTableModel();
 model->setEditStrategy(QSqlTableModel:: OnFieldChange);
 model->setTable("articles");
 model->select(); 

 // Remember the indexes of the columns:
 positionIdx = model->fieldIndex("position");

 // Set the relations to the database table 'positions':
 model->setRelation(positionIdx, QSqlRelation("positions", "id", "name"));

 // articlesTable is a QTableView, set it's model
 ui.articlesTable->setModel(model);

The problem:
-I add a new record in database table 'positions'
-I call model->select()  (to refresh articlesTable)
-the new record is not displayed in the combo box of field 'positions'

I must close the form and reopen it in order for this field to display the new record.
How can I fix this?