[Qt-interest] How to get DoubleSpinBox to display null value using QDataWidgetMapper

[bar tomas]

Hi,

I'm using QDataWidgetMapper to create a form-like interface to a database table.
I've mapped a DoubleSpinBox to a float field in my table.
However, even when this field contains a null value in my database,
the DoubleSpinBox displays the value 0.00.
I would like the DoubleSpinBox to display blank when the value is null
in the database.
What would be the simplest way to do this?
Many thanks