Thank you for answering this.

> TIB_DSQL expects the return of at least one row if it is a singleton
> select.

If this is how it's supposed to work then the help files should at
least mention this and the error message should be more explicit like:
"Error: the select didn't returned any rows!" and not:
ISC ERROR CODE:335544374
ISC ERROR MESSAGE:
attempt to fetch past the last record in a record stream

This tells me that ibo sends the queries to the server and if there is
an error it retunrs that error to the user even if the error is
because of a limitation in the ibo or an error that ibo should deal
with.

This is like making a component that takes a number from user input
but the input is managed through a TEdit and the component does
something like:
values := StrToInt(edit.text);
So if that line breaks the user of the component gets an exception of
invalid converions (EConvertError).
Instead that component should do this:
try
values := StrToInt(edit.text);
except
on E: EConvertError do
begin
// deal with the exception like ask the user to re enter a valid
// number
// or in case of ibo raise an exception of some ibo type like
// EIB_DSQL_Error with a proper error message
end
end