Hello,
> I would like to write a simple "invert" function for numeric columns via
> EmpireDB.
> I am aware of the native SQL mechanism, but I was wondering if there is also
> a way of making this "properly":
>
> UPDATE data SET value = 1 / value WHERE key = "someKey";
>
> Any ideas how to achieve this in EmpireDB?
You can extends DBColumnExpr and implement the addSQL method with
something like
buf.append(getObjectValue(DataType.INTEGER, this.expr1, CTX_DEFAULT,
null));
buf.append(" \ ");
buf.append(getObjectValue(DataType.INTEGER, this.expr2, CTX_DEFAULT,
null));
and use it like
DBInvertExpr inv = new DBInvertExpr(db, 1, T.DATA.VALUE);
DBCommand cmd = db.createCommand();
cmd.set(T.DATA.VALUE.to(inv));
cmd.where(T.DATA.KEY.is(23));
- jan
