Updating Realm Object Properties Without Extra Variables

Introduction

Realm is a popular mobile database solution that offers seamless persistence for iOS applications. When working with Realm, you may encounter scenarios where you need to update object properties within a write transaction without creating additional variables to hold the changed values. In this blog post, we will explore how to accomplish this using the transaction methods provided by Realm.

Code Sample

class MessageViewController: UIViewController {

    @IBOutlet weak var titleTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    func updateTitle() {
        guard let realm = try? Realm() else {
            return
        }
        
        // Begin a write transaction.
        realm.beginWrite()
        
        let message = realm.objects(Message.self).first!
        message.title = titleTextField.text!
        
        // Commit the write transaction.
        try! realm.commitWrite()
    }

    @objc func backButtonTapped() {
        guard let realm = try? Realm() else {
            return
        }
        
        // Cancel the write transaction.
        realm.cancelWriteTransaction()
        dismiss()
    }
}

Explanation

The above code snippet showcases a MessageViewController class that demonstrates how to update a Realm object property without the need for additional variables. Let’s delve into the main points:

1. The updateTitle method is responsible for updating the title property of a Message object within a write transaction.
2. Inside the write transaction, initiated by realm.beginWrite(), we retrieve the first Message object from the Realm using realm.objects(Message.self).first!.
3. We assign the new title value from the titleTextField to the message.title property directly.
4. Finally, we commit the write transaction using try! realm.commitWrite() to persist the changes to the Realm database.
5. If the user taps the back button (backButtonTapped), we cancel the ongoing write transaction by calling realm.cancelWriteTransaction(). This discards any changes made within the transaction.

Conclusion

In this blog post, we explored how to update Realm object properties within a write transaction without the need for additional variables. By utilizing the beginWrite, commitWrite, and cancelWriteTransaction methods, developers can efficiently update Realm object properties while ensuring data integrity. The provided code snippet in the MessageViewController class demonstrates the straightforward process. Empowering users to update object properties without the hassle of extra variables enhances the development experience with Realm.

Thank you