Mitch wrote:

> In what circumstances would you need to use the uprepare/prepare and
> active commands?

Use Unprepare when you are done with a query and you want to free up server
resources.

Use Active when you want to open and maintain buffered records on the
client.

> Does the following code automatically close the query/dataset if it is
> open, before redoing it?
>
> > with qryCurrProjSpecs do
> > begin
> > ParamByName('Var_PVERSION_ID').asinteger := curr_proj_version;
> > Open;
> > end;

IBO does not close your dataset when you assign a value to a parameter.

What may happen is the dataset may refresh. See the RefreshOnParamChange
property.

Also, it is possible to use code in the case of multiple parameters:

MyQuery.Params.BeginUpdate;
...
MyQuery.Params.EndUpdate( );


Here is a sample procedure.

procedure Set_Query_Parameters( query : TIB_Query;
const input_paramNames : array of string;
const input_ParamValues : array of const );
type
ParamCount_t = Integer;
var
param_i : ParamCount_t;
pName : string;
pValue : TVarRec;
fieldParam : TIB_Column;
begin
with query do
begin
Prepared := true;
Params.BeginUpdate;
try
for param_i := 0 to High(input_paramNames) do
begin
pName := input_paramNames[param_i];
pValue := input_ParamValues[param_i];
fieldParam := ParamByName(pname);
with pValue do
begin
case VType of
vtInteger : fieldParam.AsInteger := VInteger;
vtBoolean : fieldParam.AsBoolean := VBoolean;
vtChar : fieldParam.AsString := VChar;
vtExtended :
begin
case fieldParam.SQLType of
Sql_Date : fieldParam.AsDateTime := VExtended^;
Sql_Float,
Sql_DFloat : fieldParam.AsFloat := VExtended^;
Sql_Double : FieldParam.AsDouble := VExtended^;
end;
end;
vtString : fieldParam.AsString := VString^;
vtPChar : fieldParam.AsString := VPChar;
vtAnsiString : fieldParam.AsString := string(VAnsiString);
vtCurrency : fieldParam.AsCurrency := VCurrency^;
else
end;
end;
end;
finally
// Make it so that there is only a single change notification even when
// multiple parameters are modified.
// If RefreshOnParamChange is true then the dataset will be refreshed
// here if it was Active to start with.
Params.EndUpdate( true );
end;
end;
end;


HTH,
Jason Wharton