What I like about my solution is you can just let the db compute the average of the ratings for any given user when it's needed.
Admittedly this gets a little hairy if you want to rank sellers according to rating in an index list, or show the ratings in such a list. On Monday, October 14, 2013 4:26:42 PM UTC-4, Niphlod wrote: > > Things can get messy in no-time with a field that is constantly > recalculated every time (e.g.) a row gets inserted into the "ratings" table. > Plan carefully those "updating functions" because if that function takes > 0.15 sec to execute, than you incur in AT LEAST 0.15 sec delay for every > insert/update/delete out there. > The way to go for "real-time" is using DAL callbacks > http://web2py.com/books/default/chapter/29/06/the-database-abstraction-layer#before-and-after-callbacks > > I'd instead go for a scheduled function that every n minutes recalculates > what is there to recalculate (and I'll plan carefully that too). > > > On Monday, October 14, 2013 10:12:26 PM UTC+2, Apple Mason wrote: >> >> Suppose I have three different types of users: buyer, distributor, and >> reseller. >> >> All buyers, distributors, and resellers have an email, password, and >> ratings. Since email and password are already part of auth_user, the >> ratings Field will be an extra field in auth_user. >> >> To separate the user roles, we can user auth_membership and auth_group to >> designate an auth_user as a 'buyer', 'distributor', or 'reseller'. >> >> Although each user role uses the same backend code for storing email and >> password (through auth_user), how would one go about storing a custom >> rating mechanism for each user role? >> >> For example, let's say: >> >> A buyer is rated with some combination of # of product reviews written >> and credible purchase history. >> >> A reseller is rated with some combination of buyer reviews and warranty >> service. >> >> A distributor is rated with reseller reviews. >> >> Assuming I have the following functions which returns on an integer with >> range 1 - 100 for ratings: >> >> def buyer_calc_rating(): # Random calcluation for this example >> comment_num = len(db(db.comments.user == db.buyer.id).select()) >> purchase_history = #... some calculation that returns int >> >> return comment_num + purchase_history >> >> def reseller_calc_rating(); # Assume similar calculation returns int >> def distributor_calc_rating(); # Assume similar calculation returns int >> >> I have two questions: >> >> - How would I go about assigning these functions to user's ratings Field >> in auth_user? >> >> - How would the ratings be dynamically updated each time something >> changes pertaining to rating calculation (ie, when a buyer rates a seller, >> etc)? >> >> Would the preferred way be to stick the above functions in a module >> which is then called wherever some controller function changes ratings? I >> would always get an update-to-date rating on the user this way (simply by >> querying 'db.auth_user.rating'), but that would also be a code-maintanence >> nightmare since I would have to keep track of all the places in the code >> that manipulates ratings? >> >> Thanks in advance. >> >> >> -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
