NSPredicate to get children's children's

问题

I want to fetch all the treatments, that are children of this List object.

I am not sure if it can be done.

I have a TableView showing all the patients of a list. Each patient can have many treatments.

I have a reference to the current list, and want to use that to somehow find the childrens children.

Thank you

回答1:

Use a fetch request for the "Treatment" entity with the predicate

[NSPredicate predicateWithFormat:@"ofPatient.ofList = %@", currentList]

using the inverse relationships from "Treatment" -> "Patient" -> "List".

来源：https://stackoverflow.com/questions/18697355/nspredicate-to-get-childrens-childrens