At 11:10 AM 11/05/2006, you wrote:

>Ok, sorry, only now I've realized it could be more verbose ;-)

Yes. The problems become immediately evident.

>The main query - IB_QueryOcorrencias:
>-----------------------------------
>select *
>from LOG_OCORRENCIAS lo
> join CAD_OCORRENCIAS co on lo.id_ocorrencia = co.id_ocorrencia
> join cad_classe_ocorrencias cco on co.id_classe_ocorrencia =
>cco.id_classe

First problems occur with the main query: the syntax is bad. Rewrite
it so that

(a) it has a column list; and
(b) each output column is properly identified.

For example,

select
lo.id_ocorrencia,
lo.field1,
co.fieldx,
cco.field_blah
from LOG_OCORRENCIAS lo
join CAD_OCORRENCIAS co on lo.id_ocorrencia = co.id_ocorrencia
join cad_classe_ocorrencias cco on co.id_classe_ocorrencia =
cco.id_classe

>The ComboBox query - IB_QueryClasseOcorrencia:
>-----------------------------------
>SELECT ID_CLASSE, DESCRICAO
>FROM CAD_CLASSE_OCORRENCIAS
>
>The code that loads the values and item values:
>-----------------------------------------------
>void __fastcall TFormCadInstalacoes::LoadCBoxClasseOcorrencia(void)
>{
> IB_CBClasseOcorrencia->Items->Clear();
> IB_CBClasseOcorrencia->ItemValues->Clear();
> IB_QueryClasseOcorrencia->Open();
> while (!IB_QueryClasseOcorrencia->Eof) {
>IB_CBClasseOcorrencia->Items->Add(IB_QueryClasseOcorrencia->FieldByName("DESCRICAO")->AsString);
>
>IB_CBClasseOcorrencia->ItemValues->Add(IB_QueryClasseOcorrencia->FieldByName("ID_CLASSE")->AsString);
> IB_QueryClasseOcorrencia->Next();
> }
> IB_QueryClasseOcorrencia->Close();
>}

This approach is inefficient. Use a TIB_Cursor to load the Items.
Let's suppose you make ib_CBClasseOcorrencia an IB_Cursor object.

IB_CBClasseOcorrencia->Items->Clear();
IB_CBClasseOcorrencia->ItemValues->Clear();
IB_QueryClasseOcorrencia->First(); <-------------------------------------
while (!IB_QueryClasseOcorrencia->Eof) {
IB_CBClasseOcorrencia->Items->Add(IB_QueryClasseOcorrencia->FieldByName("DESCRICAO")->AsString);

IB_CBClasseOcorrencia->ItemValues->Add(IB_QueryClasseOcorrencia->FieldByName("ID_CLASSE")->AsString);
IB_QueryClasseOcorrencia->Next();
}
IB_QueryClasseOcorrencia->Close();
}
The event that adds the parameter:

>-----------------------------------
>void __fastcall
>TFormCadInstalacoes::IB_QueryOcorrenciasPrepareSQL(TIB_Statement *Sender)
>{
> if (IB_CBClasseOcorrencia->ItemIndex != -1)
> IB_QueryOcorrencias->SQLWhereItems->Add("id_classe_ocorrencia
>= :id_classe_ocorrencia");
>}

No.
(1) This is not the right usage of SQLWhereItems. You use that when
you actually want to change the WHERE criteria (which you don't,
here) AND you have do this in the OnPrepareSQL event.

(2) What you REALLY want here is to place a parameterised WHERE
clause in the main query - since you are "setting it in concrete"
anyway, by binding it to your combobox.

So, here is how your your main query needs to be:

select
lo.id_ocorrencia,
lo.field1,
co.fieldx,
cco.field_blah
from LOG_OCORRENCIAS lo
join CAD_OCORRENCIAS co on lo.id_ocorrencia = co.id_ocorrencia
join cad_classe_ocorrencias cco on co.id_classe_ocorrencia =
cco.id_classe
where cco.id_classe_ocorrencia = :id_classe_ocorrencia

(Sorry if I have guessed wrong about which table has
id_classe_ocorrencia, but you get the picture.)

>Propesties of the IB_ComboBox:
>------------------------------
>DataField = blank
>DataSource= IB_DataSourceOcorrencias (which is connected to
>IB_QueryOcorrencias)
>ParamName = id_classe_ocorrencia
>
>When the user select the tab where are the controls, the program runs
>like this:
>
>LoadCBoxClasseOcorrencia();
>IB_QueryOcorrencias->InvalidateSQL();

No, don't call InvalidateSQL. **You are NOT changing the parameter,
only its value.**

What you actually want is to start with the entire main query
(INCLUDING the where clause), prepare it, and thereafter to apply a
new *value* to the parameter by way of the combobox selection.

>IB_QueryOcorrencias->Active = true;

Don't open queries by setting Active true. Use Active when you want
to to test whether an IB_Query is active; use Open on an IB_Query
the *first time* and Refresh all other times; use First on an IB_Cursor.

>And nothing is showed in the Combo.
>I hope not throwed out too much information this time. ;-)

This time it was adequate. :-)

Helen