1 files changed, 892 insertions, 0 deletions
diff --git a/contrib/plpgsql/test/triggers.sql b/contrib/plpgsql/test/triggers.sql
new file mode 100644
index 0000000000..185db97b29
--- /dev/null
+++ b/contrib/plpgsql/test/triggers.sql
@@ -0,0 +1,892 @@
+-- ************************************************************
+-- * 
+-- * Trigger procedures and functions for the patchfield
+-- * test of PL/pgSQL
+-- * 
+-- * $Header: /cvsroot/pgsql/contrib/plpgsql/test/Attic/triggers.sql,v 1.1 1998/08/22 12:38:37 momjian Exp $
+-- * 
+-- ************************************************************
+
+
+-- ************************************************************
+-- * AFTER UPDATE on Room
+-- *	- If room no changes let wall slots follow
+-- ************************************************************
+create function tg_room_au() returns opaque as '
+begin
+    if new.roomno != old.roomno then
+        update WSlot set roomno = new.roomno where roomno = old.roomno;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_room_au after update
+    on Room for each row execute procedure tg_room_au();
+
+
+-- ************************************************************
+-- * AFTER DELETE on Room
+-- *	- delete wall slots in this room
+-- ************************************************************
+create function tg_room_ad() returns opaque as '
+begin
+    delete from WSlot where roomno = old.roomno;
+    return old;
+end;
+' language 'plpgsql';
+
+create trigger tg_room_ad after delete
+    on Room for each row execute procedure tg_room_ad();
+
+
+-- ************************************************************
+-- * BEFORE INSERT or UPDATE on WSlot
+-- *	- Check that room exists
+-- ************************************************************
+create function tg_wslot_biu() returns opaque as '
+begin
+    if count(*) = 0 from Room where roomno = new.roomno then
+        raise exception ''Room % does not exist'', new.roomno;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_wslot_biu before insert or update
+    on WSlot for each row execute procedure tg_wslot_biu();
+
+
+-- ************************************************************
+-- * AFTER UPDATE on PField
+-- *	- Let PSlots of this field follow
+-- ************************************************************
+create function tg_pfield_au() returns opaque as '
+begin
+    if new.name != old.name then
+        update PSlot set pfname = new.name where pfname = old.name;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_pfield_au after update
+    on PField for each row execute procedure tg_pfield_au();
+
+
+-- ************************************************************
+-- * AFTER DELETE on PField
+-- *	- Remove all slots of this patchfield
+-- ************************************************************
+create function tg_pfield_ad() returns opaque as '
+begin
+    delete from PSlot where pfname = old.name;
+    return old;
+end;
+' language 'plpgsql';
+
+create trigger tg_pfield_ad after delete
+    on PField for each row execute procedure tg_pfield_ad();
+
+
+-- ************************************************************
+-- * BEFORE INSERT or UPDATE on PSlot
+-- *	- Ensure that our patchfield does exist
+-- ************************************************************
+create function tg_pslot_biu() returns opaque as '
+declare
+    pfrec	record;
+    rename new to ps;
+begin
+    select into pfrec * from PField where name = ps.pfname;
+    if not found then
+        raise exception ''Patchfield "%" does not exist'', ps.pfname;
+    end if;
+    return ps;
+end;
+' language 'plpgsql';
+
+create trigger tg_pslot_biu before insert or update
+    on PSlot for each row execute procedure tg_pslot_biu();
+
+
+-- ************************************************************
+-- * AFTER UPDATE on System
+-- *	- If system name changes let interfaces follow
+-- ************************************************************
+create function tg_system_au() returns opaque as '
+begin
+    if new.name != old.name then
+        update IFace set sysname = new.name where sysname = old.name;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_system_au after update
+    on System for each row execute procedure tg_system_au();
+
+
+-- ************************************************************
+-- * BEFORE INSERT or UPDATE on IFace
+-- *	- set the slotname to IF.sysname.ifname
+-- ************************************************************
+create function tg_iface_biu() returns opaque as '
+declare
+    sname	text;
+    sysrec	record;
+begin
+    select into sysrec * from system where name = new.sysname;
+    if not found then
+        raise exception ''system "%" does not exist'', new.sysname;
+    end if;
+    sname := ''IF.'' || new.sysname;
+    sname := sname || ''.'';
+    sname := sname || new.ifname;
+    if length(sname) > 20 then
+        raise exception ''IFace slotname "%" too long (20 char max)'', sname;
+    end if;
+    new.slotname := sname;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_iface_biu before insert or update
+    on IFace for each row execute procedure tg_iface_biu();
+
+
+-- ************************************************************
+-- * AFTER INSERT or UPDATE or DELETE on Hub
+-- *	- insert/delete/rename slots as required
+-- ************************************************************
+create function tg_hub_a() returns opaque as '
+declare
+    hname	text;
+    dummy	integer;
+begin
+    if tg_op = ''INSERT'' then
+	dummy := tg_hub_adjustslots(new.name, 0, new.nslots);
+	return new;
+    end if;
+    if tg_op = ''UPDATE'' then
+	if new.name != old.name then
+	    update HSlot set hubname = new.name where hubname = old.name;
+	end if;
+	dummy := tg_hub_adjustslots(new.name, old.nslots, new.nslots);
+	return new;
+    end if;
+    if tg_op = ''DELETE'' then
+	dummy := tg_hub_adjustslots(old.name, old.nslots, 0);
+	return old;
+    end if;
+end;
+' language 'plpgsql';
+
+create trigger tg_hub_a after insert or update or delete
+    on Hub for each row execute procedure tg_hub_a();
+
+
+-- ************************************************************
+-- * Support function to add/remove slots of Hub
+-- ************************************************************
+create function tg_hub_adjustslots(bpchar, integer, integer)
+returns integer as '
+declare
+    hname	alias for $1;
+    oldnslots	alias for $2;
+    newnslots	alias for $3;
+begin
+    if newnslots = oldnslots then
+        return 0;
+    end if;
+    if newnslots < oldnslots then
+        delete from HSlot where hubname = hname and slotno > newnslots;
+	return 0;
+    end if;
+    for i in oldnslots + 1 .. newnslots loop
+        insert into HSlot (slotname, hubname, slotno, slotlink)
+		values (''HS.dummy'', hname, i, '''');
+    end loop;
+    return 0;
+end;
+' language 'plpgsql';
+
+
+-- ************************************************************
+-- * BEFORE INSERT or UPDATE on HSlot
+-- *	- prevent from manual manipulation
+-- *	- set the slotname to HS.hubname.slotno
+-- ************************************************************
+create function tg_hslot_biu() returns opaque as '
+declare
+    sname	text;
+    xname	HSlot.slotname%TYPE;
+    hubrec	record;
+begin
+    select into hubrec * from Hub where name = new.hubname;
+    if not found then
+        raise exception ''no manual manipulation of HSlot'';
+    end if;
+    if new.slotno < 1 or new.slotno > hubrec.nslots then
+        raise exception ''no manual manipulation of HSlot'';
+    end if;
+    if tg_op = ''UPDATE'' then
+	if new.hubname != old.hubname then
+	    if count(*) > 0 from Hub where name = old.hubname then
+		raise exception ''no manual manipulation of HSlot'';
+	    end if;
+	end if;
+    end if;
+    sname := ''HS.'' || trim(new.hubname);
+    sname := sname || ''.'';
+    sname := sname || new.slotno::text;
+    if length(sname) > 20 then
+        raise exception ''HSlot slotname "%" too long (20 char max)'', sname;
+    end if;
+    new.slotname := sname;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_hslot_biu before insert or update
+    on HSlot for each row execute procedure tg_hslot_biu();
+
+
+-- ************************************************************
+-- * BEFORE DELETE on HSlot
+-- *	- prevent from manual manipulation
+-- ************************************************************
+create function tg_hslot_bd() returns opaque as '
+declare
+    hubrec	record;
+begin
+    select into hubrec * from Hub where name = old.hubname;
+    if not found then
+        return old;
+    end if;
+    if old.slotno > hubrec.nslots then
+        return old;
+    end if;
+    raise exception ''no manual manipulation of HSlot'';
+end;
+' language 'plpgsql';
+
+create trigger tg_hslot_bd before delete
+    on HSlot for each row execute procedure tg_hslot_bd();
+
+
+-- ************************************************************
+-- * BEFORE INSERT on all slots
+-- *	- Check name prefix
+-- ************************************************************
+create function tg_chkslotname() returns opaque as '
+begin
+    if substr(new.slotname, 1, 2) != tg_argv[0] then
+        raise exception ''slotname must begin with %'', tg_argv[0];
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_chkslotname before insert
+    on PSlot for each row execute procedure tg_chkslotname('PS');
+
+create trigger tg_chkslotname before insert
+    on WSlot for each row execute procedure tg_chkslotname('WS');
+
+create trigger tg_chkslotname before insert
+    on PLine for each row execute procedure tg_chkslotname('PL');
+
+create trigger tg_chkslotname before insert
+    on IFace for each row execute procedure tg_chkslotname('IF');
+
+create trigger tg_chkslotname before insert
+    on PHone for each row execute procedure tg_chkslotname('PH');
+
+
+-- ************************************************************
+-- * BEFORE INSERT or UPDATE on all slots with slotlink
+-- *	- Set slotlink to empty string if NULL value given
+-- ************************************************************
+create function tg_chkslotlink() returns opaque as '
+begin
+    if new.slotlink isnull then
+        new.slotlink := '''';
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_chkslotlink before insert or update
+    on PSlot for each row execute procedure tg_chkslotlink();
+
+create trigger tg_chkslotlink before insert or update
+    on WSlot for each row execute procedure tg_chkslotlink();
+
+create trigger tg_chkslotlink before insert or update
+    on IFace for each row execute procedure tg_chkslotlink();
+
+create trigger tg_chkslotlink before insert or update
+    on HSlot for each row execute procedure tg_chkslotlink();
+
+create trigger tg_chkslotlink before insert or update
+    on PHone for each row execute procedure tg_chkslotlink();
+
+
+-- ************************************************************
+-- * BEFORE INSERT or UPDATE on all slots with backlink
+-- *	- Set backlink to empty string if NULL value given
+-- ************************************************************
+create function tg_chkbacklink() returns opaque as '
+begin
+    if new.backlink isnull then
+        new.backlink := '''';
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_chkbacklink before insert or update
+    on PSlot for each row execute procedure tg_chkbacklink();
+
+create trigger tg_chkbacklink before insert or update
+    on WSlot for each row execute procedure tg_chkbacklink();
+
+create trigger tg_chkbacklink before insert or update
+    on PLine for each row execute procedure tg_chkbacklink();
+
+
+-- ************************************************************
+-- * BEFORE UPDATE on PSlot
+-- *	- do delete/insert instead of update if name changes
+-- ************************************************************
+create function tg_pslot_bu() returns opaque as '
+begin
+    if new.slotname != old.slotname then
+        delete from PSlot where slotname = old.slotname;
+	insert into PSlot (
+		    slotname,
+		    pfname,
+		    slotlink,
+		    backlink
+		) values (
+		    new.slotname,
+		    new.pfname,
+		    new.slotlink,
+		    new.backlink
+		);
+        return null;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_pslot_bu before update
+    on PSlot for each row execute procedure tg_pslot_bu();
+
+
+-- ************************************************************
+-- * BEFORE UPDATE on WSlot
+-- *	- do delete/insert instead of update if name changes
+-- ************************************************************
+create function tg_wslot_bu() returns opaque as '
+begin
+    if new.slotname != old.slotname then
+        delete from WSlot where slotname = old.slotname;
+	insert into WSlot (
+		    slotname,
+		    roomno,
+		    slotlink,
+		    backlink
+		) values (
+		    new.slotname,
+		    new.roomno,
+		    new.slotlink,
+		    new.backlink
+		);
+        return null;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_wslot_bu before update
+    on WSlot for each row execute procedure tg_Wslot_bu();
+
+
+-- ************************************************************
+-- * BEFORE UPDATE on PLine
+-- *	- do delete/insert instead of update if name changes
+-- ************************************************************
+create function tg_pline_bu() returns opaque as '
+begin
+    if new.slotname != old.slotname then
+        delete from PLine where slotname = old.slotname;
+	insert into PLine (
+		    slotname,
+		    phonenumber,
+		    comment,
+		    backlink
+		) values (
+		    new.slotname,
+		    new.phonenumber,
+		    new.comment,
+		    new.backlink
+		);
+        return null;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_pline_bu before update
+    on PLine for each row execute procedure tg_pline_bu();
+
+
+-- ************************************************************
+-- * BEFORE UPDATE on IFace
+-- *	- do delete/insert instead of update if name changes
+-- ************************************************************
+create function tg_iface_bu() returns opaque as '
+begin
+    if new.slotname != old.slotname then
+        delete from IFace where slotname = old.slotname;
+	insert into IFace (
+		    slotname,
+		    sysname,
+		    ifname,
+		    slotlink
+		) values (
+		    new.slotname,
+		    new.sysname,
+		    new.ifname,
+		    new.slotlink
+		);
+        return null;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_iface_bu before update
+    on IFace for each row execute procedure tg_iface_bu();
+
+
+-- ************************************************************
+-- * BEFORE UPDATE on HSlot
+-- *	- do delete/insert instead of update if name changes
+-- ************************************************************
+create function tg_hslot_bu() returns opaque as '
+begin
+    if new.slotname != old.slotname or new.hubname != old.hubname then
+        delete from HSlot where slotname = old.slotname;
+	insert into HSlot (
+		    slotname,
+		    hubname,
+		    slotno,
+		    slotlink
+		) values (
+		    new.slotname,
+		    new.hubname,
+		    new.slotno,
+		    new.slotlink
+		);
+        return null;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_hslot_bu before update
+    on HSlot for each row execute procedure tg_hslot_bu();
+
+
+-- ************************************************************
+-- * BEFORE UPDATE on PHone
+-- *	- do delete/insert instead of update if name changes
+-- ************************************************************
+create function tg_phone_bu() returns opaque as '
+begin
+    if new.slotname != old.slotname then
+        delete from PHone where slotname = old.slotname;
+	insert into PHone (
+		    slotname,
+		    comment,
+		    slotlink
+		) values (
+		    new.slotname,
+		    new.comment,
+		    new.slotlink
+		);
+        return null;
+    end if;
+    return new;
+end;
+' language 'plpgsql';
+
+create trigger tg_phone_bu before update
+    on PHone for each row execute procedure tg_phone_bu();
+
+
+-- ************************************************************
+-- * AFTER INSERT or UPDATE or DELETE on slot with backlink
+-- *	- Ensure that the opponent correctly points back to us
+-- ************************************************************
+create function tg_backlink_a() returns opaque as '
+declare
+    dummy	integer;
+begin
+    if tg_op = ''INSERT'' then
+        if new.backlink != '''' then
+	    dummy := tg_backlink_set(new.backlink, new.slotname);
+	end if;
+	return new;
+    end if;
+    if tg_op = ''UPDATE'' then
+        if new.backlink != old.backlink then
+	    if old.backlink != '''' then
+	        dummy := tg_backlink_unset(old.backlink, old.slotname);
+	    end if;
+	    if new.backlink != '''' then
+	        dummy := tg_backlink_set(new.backlink, new.slotname);
+	    end if;
+	else
+	    if new.slotname != old.slotname and new.backlink != '''' then
+	        dummy := tg_slotlink_set(new.backlink, new.slotname);
+	    end if;
+	end if;
+	return new;
+    end if;
+    if tg_op = ''DELETE'' then
+        if old.backlink != '''' then
+	    dummy := tg_backlink_unset(old.backlink, old.slotname);
+	end if;
+	return old;
+    end if;
+end;
+' language 'plpgsql';
+
+
+create trigger tg_backlink_a after insert or update or delete
+    on PSlot for each row execute procedure tg_backlink_a('PS');
+
+create trigger tg_backlink_a after insert or update or delete
+    on WSlot for each row execute procedure tg_backlink_a('WS');
+
+create trigger tg_backlink_a after insert or update or delete
+    on PLine for each row execute procedure tg_backlink_a('PL');
+
+
+-- ************************************************************
+-- * Support function to set the opponents backlink field
+-- * if it does not already point to the requested slot
+-- ************************************************************
+create function tg_backlink_set(bpchar, bpchar)
+returns integer as '
+declare
+    myname	alias for $1;
+    blname	alias for $2;
+    mytype	char(2);
+    link	char(4);
+    rec		record;
+begin
+    mytype := substr(myname, 1, 2);
+    link := mytype || substr(blname, 1, 2);
+    if link = ''PLPL'' then
+        raise exception 
+		''backlink between two phone lines does not make sense'';
+    end if;
+    if link in (''PLWS'', ''WSPL'') then
+        raise exception 
+		''direct link of phone line to wall slot not permitted'';
+    end if;
+    if mytype = ''PS'' then
+        select into rec * from PSlot where slotname = myname;
+	if not found then
+	    raise exception ''% does not exists'', myname;
+	end if;
+	if rec.backlink != blname then
+	    update PSlot set backlink = blname where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''WS'' then
+        select into rec * from WSlot where slotname = myname;
+	if not found then
+	    raise exception ''% does not exists'', myname;
+	end if;
+	if rec.backlink != blname then
+	    update WSlot set backlink = blname where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''PL'' then
+        select into rec * from PLine where slotname = myname;
+	if not found then
+	    raise exception ''% does not exists'', myname;
+	end if;
+	if rec.backlink != blname then
+	    update PLine set backlink = blname where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    raise exception ''illegal backlink beginning with %'', mytype;
+end;
+' language 'plpgsql';
+
+
+-- ************************************************************
+-- * Support function to clear out the backlink field if
+-- * it still points to specific slot
+-- ************************************************************
+create function tg_backlink_unset(bpchar, bpchar)
+returns integer as '
+declare
+    myname	alias for $1;
+    blname	alias for $2;
+    mytype	char(2);
+    rec		record;
+begin
+    mytype := substr(myname, 1, 2);
+    if mytype = ''PS'' then
+        select into rec * from PSlot where slotname = myname;
+	if not found then
+	    return 0;
+	end if;
+	if rec.backlink = blname then
+	    update PSlot set backlink = '''' where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''WS'' then
+        select into rec * from WSlot where slotname = myname;
+	if not found then
+	    return 0;
+	end if;
+	if rec.backlink = blname then
+	    update WSlot set backlink = '''' where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''PL'' then
+        select into rec * from PLine where slotname = myname;
+	if not found then
+	    return 0;
+	end if;
+	if rec.backlink = blname then
+	    update PLine set backlink = '''' where slotname = myname;
+	end if;
+	return 0;
+    end if;
+end;
+' language 'plpgsql';
+
+
+-- ************************************************************
+-- * AFTER INSERT or UPDATE or DELETE on slot with slotlink
+-- *	- Ensure that the opponent correctly points back to us
+-- ************************************************************
+create function tg_slotlink_a() returns opaque as '
+declare
+    dummy	integer;
+begin
+    if tg_op = ''INSERT'' then
+        if new.slotlink != '''' then
+	    dummy := tg_slotlink_set(new.slotlink, new.slotname);
+	end if;
+	return new;
+    end if;
+    if tg_op = ''UPDATE'' then
+        if new.slotlink != old.slotlink then
+	    if old.slotlink != '''' then
+	        dummy := tg_slotlink_unset(old.slotlink, old.slotname);
+	    end if;
+	    if new.slotlink != '''' then
+	        dummy := tg_slotlink_set(new.slotlink, new.slotname);
+	    end if;
+	else
+	    if new.slotname != old.slotname and new.slotlink != '''' then
+	        dummy := tg_slotlink_set(new.slotlink, new.slotname);
+	    end if;
+	end if;
+	return new;
+    end if;
+    if tg_op = ''DELETE'' then
+        if old.slotlink != '''' then
+	    dummy := tg_slotlink_unset(old.slotlink, old.slotname);
+	end if;
+	return old;
+    end if;
+end;
+' language 'plpgsql';
+
+
+create trigger tg_slotlink_a after insert or update or delete
+    on PSlot for each row execute procedure tg_slotlink_a('PS');
+
+create trigger tg_slotlink_a after insert or update or delete
+    on WSlot for each row execute procedure tg_slotlink_a('WS');
+
+create trigger tg_slotlink_a after insert or update or delete
+    on IFace for each row execute procedure tg_slotlink_a('IF');
+
+create trigger tg_slotlink_a after insert or update or delete
+    on HSlot for each row execute procedure tg_slotlink_a('HS');
+
+create trigger tg_slotlink_a after insert or update or delete
+    on PHone for each row execute procedure tg_slotlink_a('PH');
+
+
+-- ************************************************************
+-- * Support function to set the opponents slotlink field
+-- * if it does not already point to the requested slot
+-- ************************************************************
+create function tg_slotlink_set(bpchar, bpchar)
+returns integer as '
+declare
+    myname	alias for $1;
+    blname	alias for $2;
+    mytype	char(2);
+    link	char(4);
+    rec		record;
+begin
+    mytype := substr(myname, 1, 2);
+    link := mytype || substr(blname, 1, 2);
+    if link = ''PHPH'' then
+        raise exception 
+		''slotlink between two phones does not make sense'';
+    end if;
+    if link in (''PHHS'', ''HSPH'') then
+        raise exception 
+		''link of phone to hub does not make sense'';
+    end if;
+    if link in (''PHIF'', ''IFPH'') then
+        raise exception 
+		''link of phone to hub does not make sense'';
+    end if;
+    if link in (''PSWS'', ''WSPS'') then
+        raise exception 
+		''slotlink from patchslot to wallslot not permitted'';
+    end if;
+    if mytype = ''PS'' then
+        select into rec * from PSlot where slotname = myname;
+	if not found then
+	    raise exception ''% does not exists'', myname;
+	end if;
+	if rec.slotlink != blname then
+	    update PSlot set slotlink = blname where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''WS'' then
+        select into rec * from WSlot where slotname = myname;
+	if not found then
+	    raise exception ''% does not exists'', myname;
+	end if;
+	if rec.slotlink != blname then
+	    update WSlot set slotlink = blname where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''IF'' then
+        select into rec * from IFace where slotname = myname;
+	if not found then
+	    raise exception ''% does not exists'', myname;
+	end if;
+	if rec.slotlink != blname then
+	    update IFace set slotlink = blname where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''HS'' then
+        select into rec * from HSlot where slotname = myname;
+	if not found then
+	    raise exception ''% does not exists'', myname;
+	end if;
+	if rec.slotlink != blname then
+	    update HSlot set slotlink = blname where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''PH'' then
+        select into rec * from PHone where slotname = myname;
+	if not found then
+	    raise exception ''% does not exists'', myname;
+	end if;
+	if rec.slotlink != blname then
+	    update PHone set slotlink = blname where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    raise exception ''illegal slotlink beginning with %'', mytype;
+end;
+' language 'plpgsql';
+
+
+-- ************************************************************
+-- * Support function to clear out the slotlink field if
+-- * it still points to specific slot
+-- ************************************************************
+create function tg_slotlink_unset(bpchar, bpchar)
+returns integer as '
+declare
+    myname	alias for $1;
+    blname	alias for $2;
+    mytype	char(2);
+    rec		record;
+begin
+    mytype := substr(myname, 1, 2);
+    if mytype = ''PS'' then
+        select into rec * from PSlot where slotname = myname;
+	if not found then
+	    return 0;
+	end if;
+	if rec.slotlink = blname then
+	    update PSlot set slotlink = '''' where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''WS'' then
+        select into rec * from WSlot where slotname = myname;
+	if not found then
+	    return 0;
+	end if;
+	if rec.slotlink = blname then
+	    update WSlot set slotlink = '''' where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''IF'' then
+        select into rec * from IFace where slotname = myname;
+	if not found then
+	    return 0;
+	end if;
+	if rec.slotlink = blname then
+	    update IFace set slotlink = '''' where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''HS'' then
+        select into rec * from HSlot where slotname = myname;
+	if not found then
+	    return 0;
+	end if;
+	if rec.slotlink = blname then
+	    update HSlot set slotlink = '''' where slotname = myname;
+	end if;
+	return 0;
+    end if;
+    if mytype = ''PH'' then
+        select into rec * from PHone where slotname = myname;
+	if not found then
+	    return 0;
+	end if;
+	if rec.slotlink = blname then
+	    update PHone set slotlink = '''' where slotname = myname;
+	end if;
+	return 0;
+    end if;
+end;
+' language 'plpgsql';
+
+