Working with Date type in database applications

[wysota]

You can overload paint(), check if you should treat any column in a special way, mark it somehow, call original paint() and in drawDisplay check for that mark and act according to it.

There is no need to rewrite paint() code.

BTW. A quick solution would be to return the date from the database in a format of your choice, instead of converting it when you display it.

Anyway, the PROPER solution would be to reimplement the model.

[kolach]

You can overload paint(), check if you should treat any column in a special way, mark it somehow, call original paint() and in drawDisplay check for that mark and act according to it.

There is no need to rewrite paint() code.

BTW. A quick solution would be to return the date from the database in a format of your choice, instead of converting it when you display it.

Anyway, the PROPER solution would be to reimplement the model.

Yes, it is posible. But looks like hack though.

As to the model:

Model returns data in QVariant format.
In delegate I see:

QItemDelegate:: paint(...)
{
...
QString text = model->data(index, Qt:: DisplayRole).toString();
...
}
in case that data is of DATE type, toString() makes ISODate convertion.

So, as I've mentioned, model returns data in QVariant format and for the MODEL I think it is a good solution. It is responsibility of VIEW to view data in this or that way.

So it seems that QItemDelegate:: paint(...) has an ill design.

[ball]

maybe you can format the date-output using built-in sql function from database first?

like to_date(), to_string in oracle

[kolach]

maybe you can format the date-output using built-in sql function from database first?

like to_date(), to_string in oracle

If I still want (and I do!) it to be of DATE type, it will not matter.
Because QItemDelegate will call model's data(...) method that converts all received from database data to QVariant and then QItemDelegate will call QVariant::toString() -> so again ISODate conversion.

[wysota]

Yes, it is a limitation, for sure and there are probably more issues like this, but we have to cope with what we have.