Vicenzo, just a couple of thoughts. 1. Three joins is not database intense. Joining tables is what they do. Correct indexing is the key to good performance.
2. If you have found a way to get Web2py to fetch the data, it is just doing the join for you behind the scenes. Same difference. On Saturday, July 28, 2012 5:25:33 PM UTC-4, Vincenzo Ampolo wrote: > > On 07/28/2012 03:38 AM, Alec Taylor wrote: > > Vincenzo: Have you looked at: https://github.com/niphlod/w2p_tvseries > > What is that ? I can't figure out from the "objectives" section what > that application does... > > On 07/28/2012 05:37 AM, Cliff Kachinske wrote:> You need to define a set > that includes all three tables in the relation. > > > > ((db.genres.id==db.movies_genres.genres_id) & > > (db.movies_genres.movie_id==db.movies.id)) > > > > To get the set of genres for a specific movie, do > > > > | > > ((db.genres.id==db.movies_genres.genres_id)& > > (db.movies_genres.movie_id==db.movies.id)& > > (db.movies.id==1))# or whatever variable you like > > | > > > > > > Notice this query allows you to retrieve information from all three > > tables at one time. > > Which is exactly like the web2py books suggests. Btw to retrieve all the > information of a movie in one shot (so join movie with genres with casts > with pictures) may be really database intense (3 joins!) So after a bit > of hacking I figured out a simply way to accomplish the same goal: > > web2py automatically add the many-to-many sets to an instance with the > same name of the relation table. In my case I've movie.movies_genres for > each movie. Given so I can easily get the genres of a movie in a > template just doing. > > In [36]: for m in movie.movies_genres.select(): print m.genre.name > Thriller > > Best Regards, > > -- > Vincenzo Ampolo > http://vincenzo-ampolo.net > http://goshawknest.wordpress.com > --
