A
     <structname>ForeignDataWrapper</structname> object contains properties
     of the FDW (see <filename>foreign/foreign.h</filename> for details).
     <structfield>flags</structfield> is a bitwise-or'd bit mask indicating
     an extra set of options.  It can take the value
     <literal>FDW_MISSING_OK</literal>, in which case a <literal>NULL</literal>
     result is returned to the caller instead of an error for an undefined
     object.
    </para>

    <para>
<programlisting>
ForeignDataWrapper *
GetForeignDataWrapper(Oid fdwid);
</programlisting>

     This function returns a <structname>ForeignDataWrapper</structname>
     object for the foreign-data wrapper with the given OID.  A
     <structname>ForeignDataWrapper</structname> object contains properties
     of the FDW (see <filename>foreign/foreign.h</filename> for details).
    </para>

    <para>
<programlisting>
ForeignServer *
GetForeignServerExtended(Oid serverid, bits16 flags);
</programlisting>

     This function returns a <structname>ForeignServer</structname> object
     for the foreign server with the given OID.  A
     <structname>ForeignServer</structname> object contains properties
     of the server (see <filename>foreign/foreign.h</filename> for details).
     <structfield>flags</structfield> is a bitwise-or'd bit mask indicating
     an extra set of options.  It can take the value
     <literal>FSV_MISSING_OK</literal>, in which case a <literal>NULL</literal>
     result is returned to the caller instead of an error for an undefined
     object.
    </para>

    <para>
<programlisting>
ForeignServer *
GetForeignServer(Oid serverid);
</programlisting>

     This function returns a <structname>ForeignServer</structname> object
     for the foreign server with the given OID.  A
     <structname>ForeignServer</structname> object contains properties
     of the server (see <filename>foreign/foreign.h</filename> for details).
    </para>

    <para>
<programlisting>
UserMapping *
GetUserMapping(Oid userid, Oid serverid);
</programlisting>

     This function returns a <structname>UserMapping</structname> object for
     the user mapping of the given role on the given server.  (If there is no
     mapping for the specific user, it will return the mapping for
     <literal>PUBLIC</literal>, or throw error if there is none.)  A
     <structname>UserMapping</structname> object contains properties of the
     user mapping (see <filename>foreign/foreign.h</filename> for details).
    </para>

    <para>
<programlisting>
ForeignTable *
GetForeignTable(Oid relid);
</programlisting>

     This function returns a <structname>ForeignTable</structname> object for
     the foreign table with the given OID.  A
     <structname>ForeignTable</structname> object contains properties of the
     foreign table (see <filename>foreign/foreign.h</filename> for details).
    </para>

    <para>
<programlisting>
List *
GetForeignColumnOptions(Oid relid, AttrNumber attnum);
</programlisting>

     This function returns the per-column FDW options for the column with the
     given foreign table OID and attribute number, in the form of a list of
     <structname>DefElem</structname>.  NIL is returned if the column has no
     options.
    </para>

    <para>
     Some object types have name-based lookup functions in addition to the
     OID-based ones:
    </para>

    <para>
<programlisting>
ForeignDataWrapper *
GetForeignDataWrapperByName(const char *name, bool missing_ok);
</programlisting>

     This function returns a <structname>ForeignDataWrapper</structname>
     object for the foreign-data wrapper with the given name.  If the wrapper
     is not found, return NULL if missing_ok is true, otherwise raise an
     error.
    </para>

    <para>
<programlisting>
ForeignServer *
GetForeignServerByName(const char *name, bool missing_ok);
</programlisting>

     This function returns a <structname>ForeignServer</structname> object
     for the foreign server with the given name.