Lesson 12 - iOS ToDo app in Swift - Database migrations and sorting

Swift iOS iOS ToDo app in Swift - Database migrations and sorting

In the previous lesson, iOS ToDo app in Swift - Custom TableViewCell, we added task priorities to our ToDo app in Swift for iOS.

We promised to perform database migrations and learn to sort data in today's iOS development tutorial.

Realm migrations

To migrate a database basically means to modify the database schema to correspond to the new model. It's easy to do it in Realm, we just create a code block in AppDelegate, specifically in the following method:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool

Realm has a cool documentation where we can find everything needed. Our migration will look like this:

Realm.Configuration.defaultConfiguration = Realm.Configuration(
            schemaVersion: 1,
            migrationBlock: { migration, oldSchemaVersion in
                if (oldSchemaVersion < 1) {
                    migration.enumerateObjects(ofType: ToDo.className()) { oldObject, newObject in
                        newObject!["priority"] = 1
                    }
                }
})

We'll place this whole block to the


 

...End of the preview...

Premium article

Premium article

ict.social is a large database made up of manuals and tutorials, whose main goal is to provide high-quality IT education to everyone. We started out in the Czech republic, where we display roughly a million articles per month and receive plenty of gratitude from our users. Thanks to our successful establishment, we are now bringing these articles to the rest of the world.

Although we are trying to keep our content free of charge, maintaining the site is a huge effort for everyone involved. Therefore, some content (exercises and more advanced material) costs network points. Don't worry, they're really cheap :)

Article description

Requested article covers this content:

We'll learn to migrate databases of iOS apps which are already in AppStore. And also to sort and filter data (our objects) using Realm in Swift.

Limited offer: Learn all knowledge and save money

Buy articles and tests separately one by one 100 points
Buy all currently available articles in the section including all features for an exclusive price 85 points
Currently, you have 0 points
By buying this exclusive package, you'll have access to all 16 articles in this course including exercise submitting while saving $1.35. This offer is limited for the first articles only with an additional exclusive 15% discount.
You gain 85 points for adding an article to the site, or for $9.00 $7.65

Warning, by buying just this article you'll lose the limited 15% discount for the package of all the articles.

To access the article, you need 10 points
Currently, you have 0 points
You gain 10 points for adding an article to the site, or for $0.90

Before buying this article, you have to buy the previous one

Buying this article gives you unlimited access to it forever. You will learn some more and help us keep giving our site maintenance which helps you and others get better futures. It's a win-win.

This article is licensed: Premium, by buying this article, you agree with the terms of use.

You gain points by supporting our network. This is done by sending a helpful amount of money to support the site, or by creating content for the network.

You can get points immediately using:

Credit card SMS Wire transfer
Credit card SMS Wire transfer
Article has been written for you by Filip Němeček
Avatar
Activities (3)