hi,
i'm using BCB5 and DBISAM 4.22
do the WHERE command run well if the compared field is a BYTES type ?

for exemple:
SELECT idx FROM myTable WHERE field1= :Pfield1
i try also with LIKE command ...

field1 is a BYTES type..
the result dataset is always empty

Davide.

Davide,

<< i'm using BCB5 and DBISAM 4.22
do the WHERE command run well if the compared field is a BYTES type ?

for exemple:
SELECT idx FROM myTable WHERE field1= :Pfield1
i try also with LIKE command ...

field1 is a BYTES type..
the result dataset is always empty >>

Are you sure that the values are exactly identical, byte-for-byte, and that
the lengths are the same ?  If you're using an ftBytes field, then the
length of the data that you're assigning to the field must match the field
length exactly.

Here's an example for a Bytes field with a length of 10:

procedure TForm1.PopulateButtonClick(Sender: TObject);
var
  TempBytes: array[0..9] of Byte;
  I: Integer;
begin
  with DBISAMTable1 do
     begin
     Open;
     Append;
     for I:=0 to 9 do
        TempBytes[I]:=I;
     FieldByName('BytesField').SetData(@TempBytes);
     Post;
     Close;
     end;
end;

procedure TForm1.QueryButtonClick(Sender: TObject);
var
  TempBytes: Variant;
  I: Integer;
begin
  with DBISAMQuery1 do
     begin
     SQL.Text:='SELECT * FROM BytesTest WHERE BytesField=:BytesParam';
     TempBytes:=VarArrayCreate([0,9],varByte);
     for I:=0 to 9 do
        TempBytes[I]:=I;
     with ParamByName('BytesParam') do
        begin
        DataType:=ftBytes;
        Value:=TempBytes;
        end;
     Open;
     end;
end;

I would also suggest that you might want to look into using just a straight
BLOB field instead of a Bytes field.  They are easier to deal with, and are
variable in length.

--
Tim Young
Elevate Software
www.elevatesoft.com

thanks Tim, next days i'll try..


"Tim Young [Elevate Software]" <timyoung@elevatesoft.com> ha scritto nel
messaggio news:6A6F7FAB-071E-4216-8E51-20449A4BFEC7@news.elevatesoft.com...
> Davide,
>
> << i'm using BCB5 and DBISAM 4.22
> do the WHERE command run well if the compared field is a BYTES type ?
>
> for exemple:
> SELECT idx FROM myTable WHERE field1= :Pfield1
> i try also with LIKE command ...
>
> field1 is a BYTES type..
> the result dataset is always empty >>
>
> Are you sure that the values are exactly identical, byte-for-byte, and
> that the lengths are the same ?  If you're using an ftBytes field, then
> the length of the data that you're assigning to the field must match the
> field length exactly.
>
> Here's an example for a Bytes field with a length of 10:
>
> procedure TForm1.PopulateButtonClick(Sender: TObject);
> var
>   TempBytes: array[0..9] of Byte;
>   I: Integer;
> begin
>   with DBISAMTable1 do
>      begin
>      Open;
>      Append;
>      for I:=0 to 9 do
>         TempBytes[I]:=I;
>      FieldByName('BytesField').SetData(@TempBytes);
>      Post;
>      Close;
>      end;
> end;
>
> procedure TForm1.QueryButtonClick(Sender: TObject);
> var
>   TempBytes: Variant;
>   I: Integer;
> begin
>   with DBISAMQuery1 do
>      begin
>      SQL.Text:='SELECT * FROM BytesTest WHERE BytesField=:BytesParam';
>      TempBytes:=VarArrayCreate([0,9],varByte);
>      for I:=0 to 9 do
>         TempBytes[I]:=I;
>      with ParamByName('BytesParam') do
>         begin
>         DataType:=ftBytes;
>         Value:=TempBytes;
>         end;
>      Open;
>      end;
> end;
>
> I would also suggest that you might want to look into using just a
> straight BLOB field instead of a Bytes field.  They are easier to deal
> with, and are variable in length.
>
> --
> Tim Young
> Elevate Software
> www.elevatesoft.com
>
>