RE: [PHP] Question about SQL and Graph nodel trees

> -----Original Message----- > From: Tim Gallagher [mailto:tgallagher@danati.com] > Sent: Wednesday, July 21, 2010 12:49 PM > To: Andrew Ballard > Cc: php-general@lists.php.net > Subject: RE: [PHP] Question about SQL and Graph nodel trees > > Thank you for the informaiton. I did see that code but it looks like it is > formatted for MSSQL and was unable to get it to work for Mysql. > > Tim > @Tim, You'll have to migrate the stored procedures (SP) from MSSQL to MySQL (aka stored programs). Each DBMS have their own way of implementing the SP. http://dev.mysql.com/doc/refman/5.1/en/stored-programs-views.html @Andrew, interesting link! Thanks! Regards, Tommy > ________________________________________ > From: Andrew Ballard [aballard@gmail.com] > Sent: Wednesday, July 21, 2010 11:40 AM > To: Tim Gallagher > Cc: php-general@lists.php.net > Subject: Re: [PHP] Question about SQL and Graph nodel trees > > On Wed, Jul 21, 2010 at 11:04 AM, Tim Gallagher <tgallagher@danati.com> > wrote: > > I cannot be the only one that is having this problem, what are you using for > DAG (Direct Acrylic Graph)? I need to have a mesh node edge graph and am > having trouble with this? I see that Neo4j has a rest server and I can do this > in Java but I want to do it in PHP with a MYSQL or postgresql. If you are doing > something like this, can you please tell me how you are doing this. I can do a > relationship with a parent child or a nested tree, but I need to do a DAG. > > > > Thanks for the help, > > timgerr > > > > A basic approach would be to use two tables - one to store the nodes and > second table to store the edges between the nodes. As far as traversing the > graph, the best approach I have seen expands this a bit to store the full > transitive closure of the graph, rather than just the direct edges: > > > http://www.codeproject.com/KB/database/Modeling_DAGs_on_SQL_DBs.a > spx > > It is written for SQL Server, but the idea works OK (and I successfully tested it > once) in MySQL. (I imagine the same would be true for PostgreSQL.) > > The idea is to store the transitive closure (every possible path) of the entire > graph. For instance, if you have a basic graph > > A -> B -> C -> D > > it stores these paths: > > A -> B > B -> C > C -> D > A -> C > B -> D > A -> D > > The obvious downside is that edge table can get incredibly large depending > on the nature of the graph you are modeling. (The article provides much > more detail.) I did, however, import a good chunk of an Active Directory tree > (just users and groups, not the full list of > attributes) into this pattern just to test the concept, and I found that in that > case the size of the transitive closure table did not get out of hand. > > > Andrew > -- > PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: > http://www.php.net/unsub.php