Hi, thanks. I'll investigate this possibility.
John Stanton schrieb: > Something to investigate is to use an AVL tree structure with rowids as > the pointers. It would stay balanced and you could present family trees > quite simply as well as use SQL to extract data on individuals and sets > of individuals. > > Jay A. Kreibich wrote: >> On Tue, Jun 02, 2009 at 11:16:20PM +0200, Jan scratched on the wall: >> >>> Hi, >>> >>> I am planning a database for animal breeding. I need to store the >>> relations between individuals and therefore I have to build something >>> like a tree structure. But of course with two parents (There wont be >>> cloned animals in the database .-) afaik) >>> >> >> >> >>> - adjacency list (not very difficult to understand) >>> >> Also easy to work with two parents, just have a "father" column and a >> "mother" column. >> >> Adjacency lists are quick to update, but many queries can't be done >> in (standard) SQL by itself. That usually isn't a problem, and it >> doesn't sound like you'll have millions of records. >> >> >>> - nested sets (hm, more difficult) >>> >> Nested sets only work with one parent. They're also extremely >> expensive to update, although you can do some interesting tricks with >> queries. >> >> >>> - b tree (to difficult) >>> >> B-trees are more of a way to sort and access large amount of linear >> data. They're not really designed to represent data that is >> inherently tree like. >> >> >>> - ? (something I missed?) >>> >> You might want to see if you can find a copy of one of Joe Celko's >> books... either "SQL for Smarties" (which has a chapter on trees) or >> the book "Joe Celko's Trees and Hierarchies in SQL for Smarties" >> which is all about trees. >> >> That said, it sounds like you'd be well serviced by a two parent >> adjacency list and a bit of custom programming/scripting. >> >> -j >> >> > > _______________________________________________ > 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
