Re: query to select a linked list
| От | Aaron Bono |
|---|---|
| Тема | Re: query to select a linked list |
| Дата | |
| Msg-id | bf05e51c0705090629l7232a6d2we87170b2168c1c82@mail.gmail.com обсуждение исходный текст |
| Ответ на | query to select a linked list (Louis-David Mitterrand <vindex+lists-pgsql-sql@apartia.org>) |
| Ответы |
Re: query to select a linked list
|
| Список | pgsql-sql |
On 5/9/07, Louis-David Mitterrand <vindex+lists-pgsql-sql@apartia.org> wrote:
Unlike Oracle, PostgreSQL doesn't have anything like a connect by so you would need to write your own stored procedure for that (if new versions of PostgreSQL will have connect by, let me know guys).
What I did was add a little redundancy to my forum tables and had a table structure kind of like this:
forum
forum_id BIGSERIAL PK,
name VARCHAR(50)
forum_topic
forum_topic_id BIGSERIAL PK,
forum_id BIGINT FK to forum
forum_post
forum_post_id BIGSERIAL PK,
create_dt TIMESTAMP,
subject VARCHAR(255),
message TEXT,
forum_topic_id BIGINT FK to forum_topic
and if you want threading, you add a parent_forum_post_id to forum_post (this is where you get the redundancy since only the top forum_post record needs a reference to forum_topic and forum_topic wouldn't even really be needed.
-Aaron
--
==================================================================
Aaron Bono
Aranya Software Technologies, Inc.
http://www.aranya.com
http://codeelixir.com
==================================================================
Hi,
To build a threaded forum application I came up the following schema:
forum
------
id_forum | integer| not null default nextval('forum_id_forum_seq'::regclass)
id_parent| integer|
subject | text | not null
message | text |
Each message a unique id_forum and an id_parent pointing to the replied
post (empty if first post).
How can I build an elegant query to select all messages in a thread?
Thanks,
Unlike Oracle, PostgreSQL doesn't have anything like a connect by so you would need to write your own stored procedure for that (if new versions of PostgreSQL will have connect by, let me know guys).
What I did was add a little redundancy to my forum tables and had a table structure kind of like this:
forum
forum_id BIGSERIAL PK,
name VARCHAR(50)
forum_topic
forum_topic_id BIGSERIAL PK,
forum_id BIGINT FK to forum
forum_post
forum_post_id BIGSERIAL PK,
create_dt TIMESTAMP,
subject VARCHAR(255),
message TEXT,
forum_topic_id BIGINT FK to forum_topic
and if you want threading, you add a parent_forum_post_id to forum_post (this is where you get the redundancy since only the top forum_post record needs a reference to forum_topic and forum_topic wouldn't even really be needed.
-Aaron
--
==================================================================
Aaron Bono
Aranya Software Technologies, Inc.
http://www.aranya.com
http://codeelixir.com
==================================================================
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