 create trigger if not exists del_triple
   instead of delete on trip
   begin
-    update edge set ended = 'now' where edge.eid = old.eid;
+    update edge set ended = datetime('now') where edge.eid = old.eid;
   end;
 
 --
 -- type system. system nodes have keys <= 0
create table if not exists kind (
  knd integer primary key,
  foreign key (knd) references node (nid) );
--
insert or ignore into node (nid, knd, val) values

------------------------------------------------------------------
create table if not exists node (
  nid integer primary key,
  knd integer  not null default 0,
  val, -- (can be any of the sqlite primitive types)
  foreign key(knd) references kind deferrable initially deferred );

