[PyKDE] Sql prepare

[Diez B. Roggisch]

Matthias Frick wrote:
> hi i got some problems with the prepare function fo QSqlQuery
> 
> i dont get some usefull back.
> 
> here my code:
> 
> print db
> query = QSqlQuery(db)
> print query.prepare( "Select :l, lot_id from yb_lot_history where rownum 
> < 4" )
> print query.bindValue( ":l", QVariant("lot_id"), QSql.ParameterType(3))
> print query.execQuery()
> print query.isActive()
> print query.executedQuery ()
> 
> while query.next():
>    print "erg:",query.value(0).toString()
> 
> 
> and here the output:
> 
> <qtsql.QSqlDatabase object at 0x009C8B70>
> True
> None
> True
> True
> Select :l, lot_id from yb_lot_history where rownum < 4
> erg: lot_id
> erg: lot_id
> erg: lot_id

That won't work, as binding parameters fills in the _value_ of that 
parameter. So it is equivalent to

select 'lot_id', lot_id from ....

I fear you can't do what you want - you have to create the sql statement 
directly with strings:

"select " + column_name + " from ..."


Regards,

Diez