QSqlRelational ComboBox Delegate doesn't work with items more than 255

[Swerved]

Qt 5.7.0:

I have a relation set up whereby there are more than 255 items in the combobox delegate.

Changing the data structure is /not/ an option as this is an interface for a database I haven't created.

Essentially the problem is thus:

• Set up relation delegate on column that has more than 255 items in the delegate
• Change the item index in the QSqlRelationalTableView to any item after index 255.
• The combobox reverts.
• Similarly, if the current index of the delegate is > 255 and I enter the editor, the current index automatically changes to 0.

Does anybody have any idea what solutions I could use for this?

[SGaist]

Hi,

Can you show the code you are using for that to happen ?

[Swerved]

The table referencing in table_name is the table that I have loaded from the db.
A column may contain a range from 1-1000 (as an example), which I then use relationmap table to get the information I need (a relation table, the uid and name) to set up the itemDelegateforColumn.

It works fine, for most things, but if I am using the delegate to convert ids for a whole bunch of person ids for example (which there can be hundreds), it just doesn't work when using the delegate.

I am also using an Access DB for this, in case this information is of any use. I don't really have a choice to change that. Though I could see if its an issue using similar data in a SQL DB instead.

Anyway, here's the relevant code, inside a function called setupTable(), which decides what table model type to use, depending on a user setting. (SqlTableModel or SqlRelationalTableModel).

QSqlRelationalTableModel *editor = new QSqlRelationalTableModel(this);
                   editor->setTable(table_name);
                   editor->setEditStrategy(QSqlTableModel::OnFieldChange);
                   // Setup table relations.
                   QStringList columndelegateid;
                   QStringList columndelegatename;
                   for (int i = 0; i < relations.size(); i++) // relations is a QStringList comprising all relations for each column.
                   {
                       QString current_index = relations.at(i);
                       QStringList record = current_index.split(",");
                       editor->setRelation(record.at(0).toInt(), QSqlRelation(record.at(1), record.at(2), record.at(3)));
                       columndelegateid << record.at(0);
                       columndelegatename << record.at(1);
                   }
                   // Setup table headers
                   QSqlQuery rcol;
                   rcol.exec("SELECT * FROM relationmap WHERE tbl = '"+table_name+"' ORDER BY UID ASC");
                   while (rcol.next())
                   {
                       editor->setHeaderData(result2.toInt(), Qt::Horizontal, result);
                   }
                   rcol.clear();
                   //Selecting the model
                   editor->setSort(0, Qt::AscendingOrder);
                   while (editor->canFetchMore())
                   {
                       editor->fetchMore();
                   }
                   editor->select();

                   ui->advanced_editor_table->setModel(editor);
                   for (int i = 0; i < columndelegateid.size(); i++)
                   {
                       QSqlQuery checktableexists;
                       if (!checktableexists.exec("SELECT Count(*) AS Count FROM "+columndelegatename.at(i)+""))
                       {
                           emit sendNotice("Error in query", ""+check+" does not exist");
                       }
                       else
                       {
                           ui->advanced_editor_table->setItemDelegateForColumn(columndelegateid.at(i).toInt(), new QSqlRelationalDelegate(ui->advanced_editor_table));
                       }
					   checktableexists.clear();
                   }
                   ui->advanced_editor_table->verticalHeader()->hide();
                   ui->advanced_editor_table->show();

[SGaist]

One thing that I find surprising is the call to select on "editor" after calling fetchMore.

Also, you should consider using a bit more intermediate variables, your code, while not pretty big, is not verbose enough to be easy to follow.