ubstitutions
    described above would give a query tree in which the result
    relation points at a subquery range-table entry, which will not
    work.  There are several ways in which <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
    can support the appearance of updating a view, however.</P
><P
>    If the subquery selects from a single base relation and is simple
    enough, the rewriter can automatically replace the subquery with the
    underlying base relation so that the <TT
CLASS="COMMAND"
>INSER