Hi,

Thank you very much for your attempt to help me.
It's a great solution.
I found another solution but not so beautiful than yours.
I changed the structure of my table and finally, I use parameters only once each....

bye
Laurent.

--- In IBObjects@yahoogroups.com, Svein Erling Tysvær <svein.erling.tysvaer@...> wrote:
>
> >> Parameters are not variables. "Named parameters" in Delphi are
> >> place-holders for members of a positional structure that is described in the API as a list of "?". So
> >> your query is passed as select * from T
> >> where (? > '' and T.F1 = ?)
> >> or (? > '' and T.F1 = ?)
> >> along with a list of XSQLVAR structures (?,?,?,?) into which the engine will return a "template"
> >> describing type and size for each late-bound value, in matching order.
> >>
> >> If you pass four parameters in a statement then you need to describe four parameters and assign values
> >> to each one distinctly, thus:
> >>
> >> select * from T
> >> where (:P1a > '' and T.F1 = :P1b)
> >> or (:P2a > '' and T.F1 = :P2b)
> >>
> >> For the late-binding, you assign as follows:
> >>
> >> ParamByName('P1a').AsWhatever := Var1; ParamByName('P1b').AsWhatever
> >> := Var1; ParamByName('P2a').AsWhatever := Var2;
> >> ParamByName('P2b').AsWhatever := Var2;
> >
> > With my little mind, I thought that parameters are processed at IBO level but not passed to FIREBIRD's
> > API (or something like that).
> >
> > I use FIREBIRD, IBO and DELPHI since a long time but I never took the time to understand what IBO really
> > does or how it works...
>
> Hi Laurent!
>
> I don't doubt Helen is right, but still my big head with a malfunctioning brain thinks similar to you. If things are identical, I expect IBO to allow me to use a parameter twice. Though that requires all references to the parameter to have identical type, so I'd change your original query to:
>
> select * from T
> where (CAST(:P1 AS VARCHAR(32)) > '' and T.F1 = :P1)
> or (CAST(:P2 AS VARCHAR(32)) > '' and T.F1 = :P2)
>
> At least, when I do this change in IB_SQL, the number of parameters change from 4 to 2. Note, though, that the parameter gets cs = NONE, so I guess I'd probably use (CAST(:P1 AS VARCHAR(32) CHARACTER SET UTF8) if T.F1 uses that character set.
>
> HTH,
> Set
>