Filter entities with a relationship(One-to-Many) a.k.a a list that has element equal to something

Question

Good afternoon, y'all

Given

Routine (Entity)

Relationship: weekdays, Destination: Weekday, Inverse: routine

Weekday (Entity)

Attribute: int (Integer 64)

Relationship: routine, Destination: Routine, Inverse: weekdays

Objective

Filter all routines with a relationship, weekdays, that contains a Weekday whose attribute int is equal to an Integer64 that you specify.

My Attempts so far

// Constant
let weekDay = 1

// Attempt 1
let attemptedNSPredicate = NSPredicate(format: "ANY weekdays.int == %@", weekDay)

// Attempt 2
let attemptedNSPredicate = NSPredicate(format: "SUBQUERY(weekdays, weekday, weekday.int == %@", weekday)

// Attempt 3
let attemptedNSPredicate = NSPredicate(format: "ANY %K.int == %@", \Routine.weekdays, weekday)

What is your solution to this problem

func yourSolution(_ solution: NSPredicate) -> FetchRequset {
     FetchRequest<Routine>(
          entity: Routine.entity(),
          sortDescriptors: [],
          predicate: solution
     )
)

Answer 1

If weekdays is an Int64 attribute, then you should tell the format to use it like that -> %ld instead of %@.

So #3 would be the right one to use with that little modification:

let attemptedNSPredicate = NSPredicate(format: "ANY %K.int == %ld", \Routine.weekdays, weekday)

In your case the relationship does not make too much sense though. Weekdays is a finite set. So making it an enum and using it as a property of Routine directly would make things a lot simpler and faster.