Swift Realm: After Writing Transaction Reference Set to Nil

Realm-iOS: Object reference set to nil after save

For all Realm Swift properties (except for List), you need to declare the properties as dynamic. Changing your model definitions to the following should help!

class Company:Object {
    dynamic var name:String = ""
    dynamic var employee:Employee?

    override static func primaryKey() -> String? {
       return "name"
   }
}

class Employee:Object {
   dynamic var name:String = ""
   dynamic var age:Int = 0

   override static func primaryKey() -> String? {
      return "name"
   }
}

Realm object as member is nil after saving

After comparing this code to one of the Realm sample projects, it would appear that simply setting an Object as a child of another does not implicitly write it to the database as well.

Instead, you may need to refactor your code slightly, but make sure you explicitly add your Medicine object to Realm in a write transaction, before you set its relation to MedPack and then write MedPack to the database.

Realm-iOS: Model object becomes nil when it's added to realm

You should keep strong reference to your Article objects. When you load them from realm you need keep them in array. if you operate on results from realm they are released when method TableViewCell setupFavIcon ends.

Realm Swift - save a reference to another object

You need to change the declaration of workoutReference. First of all, you need to make it Optional by writing ? after the type. Secondly, you shouldn't assign a default value to it, it needs to be Optional for a reason. The linked docs clearly state that

to-one relationships must be optional

, and workoutReference is clearly a to-one relationship.

class FavouriteObject: Object {
    @objc dynamic var favouriteWorkoutName = ""
    @objc dynamic var workoutReference:WorkoutSessionObject?

    override class func primaryKey() -> String? {
        return "favouriteWorkoutName"
    }
}

What's the correct way to delete all future occurrences of a Realm object?

What I typically do is create a unique NSPredicate for each constraint you want to place on the collection. You can mix and match each predicate to form a unique set of filters. For example:

extension NSPredicate {
    static func transactionDescriptionEqualTo(_ description: String?) -> NSPredicate {
        if let description = description {
            return .init(format: "transactionDescription == %@", description)
        }
        return .init(format: "transactionDescription == nil")
    }

    static func transactionCategoryEqualTo(_ category: Category?) -> NSPredicate {
        if let category = category {
            return .init(format: "transactionCategory == %@", category)
        }
        return .init(format: "transactionCategory == nil")
    }

    static func transactionDateIsAfter(_ date: Date) -> NSPredicate {
        return .init(format: "transactionDate >= %@", date as NSDate)
    }

    static func transactionIDNotEqualTo(_ id: String) -> NSPredicate {
        return .init(format: "transactionID != %@", id)
    }

    static func futureRepeats(of transaction: Transaction) -> NSPredicate {
        return NSCompoundPredicate(andPredicateWithSubpredicates: [
            .transactionDescriptionEqualTo(transaction.transactionDescription),
            .transactionCategoryEqualTo(transaction.transactionCategory),
            .transactionDateIsAfter(transaction.transactionDate),
            .transactionIDNotEqualTo(transaction.transactionID),
        ])
    }
}

Also note that you don't need to loop over the results. You can delete all objects in the results like this:

let realm = try Realm()
try realm.write {
    realm.delete(transactions.filter(.futureRepeats(of: transaction)))
}

Lastly, it's a good idea to include the transactionID as a constraint. Otherwise the original transaction will be included in the results.

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