Recursive types? - Mailing list pgsql-hackers

From John Hansen
Subject Recursive types?
Date
Msg-id 5066E5A966339E42AA04BA10BA706AE5628F@rodrick.geeknet.com.au
Whole thread Raw
Responses Re: Recursive types?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Consider the following:

create table foo ( id serial primary key, path text);
alter table foo add ref foo;
                          Table "public.foo"Column |  Type   |                      Modifiers
--------+---------+-----------------------------------------------------id     | integer | not null default
nextval('public.foo_id_seq'::text)path  | text    |ref    | foo     | 
Indexes:   "foo_pkey" PRIMARY KEY, btree (id)


insert into foo (path) VALUES ('/');
insert into foo (path,ref) VALUES ('/foo',ROW(1,'/',NULL));
insert into foo (path,ref) VALUES
('/foo/bar',ROW(2,'/foo',ROW(1,'/',NULL)));

select * from foo;id |   path   |        ref
----+----------+------------------- 1 | /        | 2 | /foo     | (1,/,) 3 | /foo/bar | (2,/foo,"(1,/,)")
(3 rows)

However, it is not possible to create such a type using create type, as
there is no alter type, even tho alter table does the same thing.

Is this a bug or a random feature?

It is also not possible to dump and restore this using pg_dump.

... John


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