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Editorial Team
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Asked: 2026-05-21T05:40:39+00:00

Is there a way to formulate a Core Data predicate for a given object,

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Is there a way to formulate a Core Data predicate for a given object, representing the head of a singly linked list, and all of the other objects in that list?

E.g., I have objects, each of which has a relationship to another object (say nextObject) and I want a predicate for a specified object and all other objects reachable by traversing nextObject (until it is nil).

CLARIFICATION:

I’m using these for a UITableView‘s NSFetchedResultsController, so these need to be part of the fetch, not something I iterate through in code.

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1 Answer

  1. Editorial Team

    You wouldn’t use a predicate for a linked list. Instead, you would just start with the first object of interest and walk the relationships by calling nextObject until you hit one that did not have a nextObject value.

    You can find the first and last objects with a predicate in a fetch just by looking for previousObject==nil and nextObject==nil.

    Predicates do not understand arbitrarily long relationship chains. They understand a chain like enity1.entity2.entity3 but not nextObject.nextObject.nextObject... because they have no way of knowing when to stop.

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