On Jul 16, 2009, at 07:28, Sean Kline wrote:

Imagine the following example:

Entity               Attributes          Relationships

WeeklyMenu date menuItems (To-many Destination: MenuItems)

MenuItems        dish                   week (Destination: WeeklyMenu)
                       chef
                       cost

Category           chef
                       dish

Chef                    Dish

LunchChef          BLT
LunchChef          Soup
DinnerChef          Soup
DinnerChef          Salad
DinnerChef          Steak

When a new date is created, I want MenuItems to automatically have records corresponding to all of the categories. How would you do this? The example is a bit contrived but is analogous to my actual application. The idea is to have the same categories every week with varying prices. Feel free to suggest a different model if mine is not appropriate. I am able to construct
an interface which allows for new dates and displays the pre-populated
categories, but I am having difficulty figuring out how to create the
MenuItems automatically.

(I compressed blank lines from your example for brevity.)

Since you always want to add menu items for the same set of categories, it's easiest to implement an override of awakeFromInsert:, then create them and set their week relationship in there.

Note that your MenuItems entity should really be called MenuItem, since there's a different instance for each chef/dish combination (assuming I'm reading your example right.) Typically, it's correct for a to-many relationship to be plural and the related-to entity to be singular.


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