ows in
   <TT
CLASS="STRUCTNAME"
>test1</TT
> and only a few rows (perhaps zero
   or one) that would be returned by such a query, this is clearly an
   inefficient method.  But if the system has been instructed to maintain an
   index on the <TT
CLASS="STRUCTFIELD"
>id</TT
> column, it can use a more
   efficient method for locating matching rows.  For instance, it
   might only have to walk a few levels deep into a search tree.
  </P
><P
>   A similar approach is used in most non-fiction books:  terms and