Why do INSERT and DELETE screw up QTableView (Qt, C++, sqlite)? - c++

Question

After setting an INSERT or DELETE query on QSqlQueryModel, my QTableView becomes screwed up. For example I hid the ID column by calling view->hideColumn(ID); but after an INSERT or DELETE the ID column becomes visible.
How can I automatically reset my view to the previous settings in these cases?

Answer 1

I guess the problem is in QSqlQueryModel::setQuery you're eventually calling every time content gets reloaded and rows inserts\deletes. Looking at the setQuery implementation I would suggest: depending on the query your model can be reset including columns settings change which should trigger view columns update.
As Qt documentation suggests:
The QSqlQueryModel class provides a
read-only data model for SQL result
sets.
so I would use direct QSqlQuery calls for the data updates and then would reload the model with the same query. Or consider switching to QSQLTableModel, which is quite handy for single table content manipulation and supports inserts updates and deletes. See if an example below would work for you:
set up database, view and model:
QSqlTableModel *_model;
QTableView *_view;
...
QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName(":memory:");
db.open() ;
QSqlQuery query;
query.prepare("CREATE TABLE IF NOT EXISTS person (id INTEGER UNIQUE PRIMARY KEY, name VARCHAR(30))");
query.exec();
query.prepare("INSERT INTO person (name) VALUES ('test1')");
query.exec();
query.prepare("INSERT INTO person (name) VALUES ('test2')");
query.exec();
_model = new QSqlTableModel(this, db);
_model->setTable("person");
_model->setEditStrategy(QSqlTableModel::OnManualSubmit);
_model->select();
_model->setHeaderData(1, Qt::Horizontal, tr("name"));
_model->setSort(1, Qt::AscendingOrder);
_view = new QTableView(this);
_view->setModel(_model);
_view->hideColumn(0);
add new row:
QSqlRecord record;
_model->insertRecord(-1, record);
delete selected row(s):
QModelIndexList selected = _view->selectionModel()->selectedIndexes();
for (int i = 0; i < selected.size(); ++i)
_model->removeRows(selected.at(i).row(), 1);
submit changes:
_model->submitAll();
hope this helps, regards