Re: inheritance

From: "Joshua b(dot) Jore" <josh(at)greentechnologist(dot)org>
To: ktt <kestutis98(at)yahoo(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: inheritance
Date: 2002-06-05 13:01:39
Message-ID: Pine.BSO.4.44.0206050744320.17988-100000@kitten.greentechnologist.org
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Impatient? That was six seconds from first to second post.

So the gist of what you are getting is that you'd like to have a many/many
relationship between your urls and other stuff? This isn't a hard thing at
all and inheritance has nothing to do with it. Just create a table
structure like the article says and you use joins to get the data back
together.

CREATE TABLE users (
user_id SERIAL
PRIMARY KEY,
username VARCHAR(32)
NOT NULL
UNIQUE
CHECK (username != '')
);

CREATE TABLE urls (
url_id SERIAL
PRIMARY KEY,
url TEXT
NOT NULL
UNIQUE
CHECK (url != '')
);

And what you asked for:

CREATE TABLE rel_users_urls (
r_u_b_id SERIAL
PRIMARY KEY,
user_id INTEGER
NOT NULL
REFERENCES users
ON UPDATE CASCADE
ON DELETE CASCADE,
url_id INTEGER
NOT NULL
REFERENCES urls
ON UPDATE CASCADE
ON DELETE CASCADE,
UNIQUE (user_id, url_id)
);

SELECT
us.username,
ur.url
FROM users AS us, urls AS ur, rel_users_urls AS uur
WHERE us.user_id = uur.user_id AND uur.url_id = ur.url_id
ORDER BY us.username, ur.url;

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On Wed, 5 Jun 2002, ktt wrote:

> hello,
>
> I would like to collect indexes of a few other tables
> into one table in order to access their values more
> easier.
> like in "urls" table here:
>
> http://www.phpbuilder.com/columns/barry20000731.php3?page=4
>
> But inserting the same values into many tables isn't
> very convienent.
> Shoul I use inherited tables, aliases, joins?
> That metho is the most effective here?
> PHP will be used to manipulate the data.
>
> thank you in advance,
>
> ktt
>
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