[thelist] Nested Queries

[rudy]

> Or am I missing something?

possibly

a parent-child or one-to-many relationship has the foreign key in the child

create table treetable
  ( id integer primary key
, name varchar(20) not null
, parent_id integer null
     references (treetable)
)

this structure not only allows the database to enforce relation integrity,
it makes for simpler queries

if you store child keys in the parent record, you essentially need one
parent-to-child row for each instance of the relationship, and then you
must either set the parent name to null or make it redundant -- an
ungainly, inlikeable structure either way

while database enforced relational integrity is possible(*) with the parent
record containing the child key, you still have twice as many rows in the
table as you really need, and twice as much traffic for inserts and deletes

(*) cascading deletes would work -- just backwards from what you'd expect!!

rudy