Dear Cariotoglou Mike, are you referring to an mysql link in the previous post? thanks, Michael
On Wed, Oct 14, 2009 at 11:33 AM, Cariotoglou Mike <m...@singular.gr> wrote: > just to throw in my two bits: > > I have done a lot of work with trees in SQL, and IMHO, the best method BY > FAR is the one described in the link below (mysql article), mainly due to > its capability to handle siblings and descendants. > for example, the self-join, parent_node method described elsewhere in this > list is failr ok for simple requirements, but is completely useles in the > following cases: > > select all_descendans_on_any depth for a particular node > > find out if a node "belongs" to a parent which is not its immediate parent. > > in other words, SET operations are quite difficult in the node-parent > relation, but very easy and efficient in the adjacent list model. > > I personally stopped looking for a better solution once I came across and > comprehended the power of this method... > > > -----Original Message----- > > From: sqlite-users-boun...@sqlite.org > > [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of > > Sebastian Bermudez > > Sent: Wednesday, October 14, 2009 5:10 PM > > To: General Discussion of SQLite Database > > Subject: Re: [sqlite] how to represent a tree in SQL > > > > > > > > look this: > > > > http://dev.mysql.com/tech-resources/articles/hierarchical-data.html > > > > is for mysql but aplies to every sql DB > > > > > > ----- Mensaje original ---- > > De: Michael Chen <vancouver.mich...@gmail.com> > > Para: sqlite-users@sqlite.org > > Enviado: mié, octubre 14, 2009 10:40:45 AM > > Asunto: [sqlite] how to represent a tree in SQL > > > > Dear there, > > > > I am developing a numerical application, where a single > > rooted dynamic tree is the main data structure. I intended to > > use SQLite for this purpose and also for other data as well. > > However I have no reference how to represent a tree using > > tables. I need these functionalities: > > (1) basic tree: single root, multi-levels, arbitrary number > > of branches, index each node, index each path (from root to a > > leaf), lookup parent, lookup descendants > > (2) dynamics: delete a path, add a path; maintain parent and > > descendants table; maintain history of tree; lookup history > > (3) each node has lots of matrix and vectors, which will be > > updated with dynamics, and should be tracked > > > > As you see, it is nontrivial to write a tree structure to > > support all these functions, while keep the code clean and > > neat. That's why I want to use SQLite to keep things > > straight. Is there a good reference on this? > > > > Michael Chen > > _______________________________________________ > > sqlite-users mailing list > > sqlite-users@sqlite.org > > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > > > > > > > Yahoo! Cocina > > > > Encontra las mejores recetas con Yahoo! Cocina. > > > > > > http://ar.mujer.yahoo.com/cocina/ > > _______________________________________________ > > sqlite-users mailing list > > sqlite-users@sqlite.org > > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- Best regards, Michael Chen Google Voice Phone.: 847-448-0647 _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
