In MSEgui version of SQLdb a persistent tfield with ftBoolean can be used for a ftSmalint column. In tibconnection:
procedure TIBConnection.SetParameters(cursor: TSQLCursor; AParams: TmseParams);
...
case paramtypes[sqlvarnr] of
...
ftInteger,ftsmallint : begin
if datatype = ftboolean then begin
i:= 0;
if asboolean then begin
i:= 1;
end;
end
else begin
i:= AsInteger;
end;
Move(i, po1^.SQLData^,po1^.SQLLen);
...