Is it really necessary to insert an 'empty' record for the root node?
The 'a' record from my experiments seems to be quite suited for the
task, unless I'm missing something.
The root should be and it will be unremovable, because of foreign keys. But it
can be, of course, not empty.
alter table foo add foreign key subpath( path, 0, -1) references foo(
path )
deferrable initially deferred,;
IIRC, you can define equality for custom types depending on the
direction of the comparison. Isn't something like that possible for
foreign keys? You'd be able to check whether the left hand of the
comparison is a parent of the right hand and vice versa. That'd be just
what we need...
Sorry, I don't know. I don't think that pgsql allows to use particular operator
for foreign key...
I must be missing something, you've obviously put a lot of thought in
ltree. Maybe it'll be possible with a future version of PostgreSQL :)
Make a patch to allow function in FK :)
--
Teodor Sigaev E-mail: teodor@xxxxxxxxx
WWW: http://www.sigaev.ru/
