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.
