RE: [PHP-DB] Help needed creating a social network

My first thought was recursion - repeat the call for each element of the result set, numbering each so you can find each level, until nothing is returned. That would probably work, but oh, what a mess. That triggered something ... off to consult Joe Celko's SQL for Smarties. He has a whole chapter on Trees, and guess what: they're not easily done in relational databases. To try and condense it here would be, shall we say, impractical. Check with a library, or try googling for trees -- hey, look what turned up:

        http://www.dbmsmag.com/9603d06.html

by JC himself. Have fun - Miles Thompson At 03:19 PM 3/7/2006, Daevid Vincent wrote:

Thanks for the reply. However, that only gives me a single degree. I'm looking for the way to traverse a 'tree' to see who is in your extended networks, so I can do things like: You are 4 degrees away from Sam: You know bob who knows john who knows carrol who knows Sam. Sam <- carrol <- john <- bob <- you Etc. -----Original Message----- From: Micah Stevens [mailto:micah@raincross-tech.com] Sent: Monday, March 06, 2006 10:28 PM To: php-db@lists.php.net Subject: Re: [PHP-DB] Help needed creating a social network CREATE TABLE users (userID int(11) not null auto_increment, primary key(userID), name tinytext not null, email tinytext not null); CREATE TABLE links (userID int(11), key (userID), friendID int(11), key(friendID)); <?php $friends = mysql_query("select users.name, users.userID from users left join links on links.friendID = users.userID where links.userID = {$_GET['userID']}"); echo "<h1>You have friends!!</h1>"; while ($f = mysql_fetch_assoc($friends)) { echo "<a href='socialnetwork.php?userID={$f['userID']}'>{$f['name']}</a

<br>\n";

} publish(); profit($greatly); do (!$use) {

      coldfusion('Cause it sucks');

} ?> (har har) On Monday 06 March 2006 9:47 pm, Daevid Vincent wrote:

Anyone have some pointers at a HowTo on creating a social network? Basically I need to show people in your immediate network,

and also friends

of your friends, etc... Like the whole 'six degrees of

separation' thing.

Ala: myspace, friendster, etc. ad nauseum. I prefer mySQL and PHP, but I could port from most any

code. I guess I'm

mostly interested in the theory of this an how do I set up

the tables

properly and what is the magic incantation (JOIN) to get

this "chain" of

people.

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