QTableView and QSqlTableModel problem

[Misenko]

Hi.

I want to know how to make sure that I wont can let some cell of my view empty.
For example I doubleclicked cell and started write. I rite something and than I press enter or tab or arrow. But when I write nothing, when I let the cell empty and press enter or tab or narrow or click somewhere I want to application set the empty cell as current and call edit().
It sounds pretty easy but I dont know which signal may i use. I tried to use dataChanged with top and bottom modelindexes but it doesnt work and I dont know why. Thisi im the code:

void DB::dataChanged(const QModelIndex &top, const QModelIndex &bottom)
{
	if(!top.isValid())
		return;
	QString data;
	data = top.data().toString();
	if (data.isEmpty())
	{
		view->setCurrentIndex(top);
		view->edit(top);
	}

void DB::dataChanged(const QModelIndex &top, const QModelIndex &bottom)
{
	if(!top.isValid())
		return;
	QString data;
	data = top.data().toString();
	if (data.isEmpty())
	{
		view->setCurrentIndex(top);
		view->edit(top);
	}

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I tried some other signals from QTableView and QSqlTableModel but nothing works perfectly for me.

Can anyone help me?