QAbstractItemModel::dataChanged fires two times for single cell change

[boo9]

I am using QSqlTableModel + QTableView
Why does the QAbstractItemModel::dataChanged signal fires two times for single cell data change.
- first signal marks single cell changed
- second signal marks entire row

debug trace:
onTableDataChanged top.left.ndx(9,5) bottom.righ.ndx(9,5) rules.size=0
onTableDataChanged top.left.ndx(9,0) bottom.righ.ndx(9,10) rules.size=0

debug trace:
onTableDataChanged top.left.ndx(9,5) bottom.righ.ndx(9,5) rules.size=0
onTableDataChanged top.left.ndx(9,0) bottom.righ.ndx(9,10) rules.size=0

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[anda_skoa]

Looks like two different signal emits to me, so they might caused by different things.

Cheers,
_