2014-08-16 21:45 GMT+02:00 Aaron Law <aaron...@gmail.com>: > > Hi all, > > I have php web programming background, and new to Django. I am helping my > brother to build an online system to manage inventory, and I've got a > database design & coding problem recently. Needing help! > > That is, I have a set of tables of "possible products", "inventory", > "suppiler", etc. I want to attach a "comment" to each of them. Therefore, I > think I should make a generic "comment" table to hold all the comments of > products, inventory, suppiler. > > -- > possible_products > id: int (pk) > name: varchar > url: varchar > price: decimal > created_at: datetime > updated_at: datetime > -- > comments > id: int (pk) > parent_id: int (fk) > content: text > author: int (fk) > table: char (which the table this comment belongs to) > created_at: datetime > updated_at: datatime > -- > > My problem is, when "possible_products" table is the parent of "comment", > then a foreign key of the parent (id number) is stored in the "comment" > table in order to link up them. > > However, how about the fk of the "inventory" table and the "suppiler" > table? It should not be that: I create 2 more columns of "inventory_id" nor > "suppiler_id" in "comments" table. (That is, I should not create the 4th > column when I want to link up the 4th parent table.) > > So, Should I use generic forgien key of Django? (so that, my "comment" > table design is right.) And how to use/implement it? >
You SHOULD rather create an abstract ProductBase model class with a ManyToMany Field pointing to Comment class and then inherit ProductBase for each specific products. Most of the time class names are singular. > P.S I mainly develop the system in the Admin section of Django. > See also: django polymorphic. -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at http://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAL7_Mo-E1-ZNBk9%2Bh6ggKfs335Z6ai2r7xuUrRr8wYr9YB9b3g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
