--- title: Data Types slug: docs/ios/parse-swift-sdk/data-objects/data-types description: In this guide you will lear how to store objects with different type of properties. image: https://www.back4app.com/images/logo-social.png docTags: createdAt: 2024-03-11T11:27:29.183Z --- # Parse data types on Swift ## Introduction When saving data on a Back4App Database, each entity is stored in a key-value pair format. The data type for the value field goes from the fundamental ones (such as **String**, **Int**, **Double**, **Float**, and **Bool**) to more complex structures. The main requirement for storing data on a Back4App Database is that the entity has to conform the **ParseSwift** protocol. On its turn, this protocol provides a set of methods to store, update and delete any instance of an entity. In this guide, you will learn how to create and setup an entity to save it on your Back4App Database. In the project example the entity we are storing encloses information about a Recipe. This tutorial uses a basic app created in Xcode 12 and **iOS 14**. :::hint{type="success"} At any time, you can access the complete Project via our GitHub repositories. - [iOS Example Repository](https://github.com/templates-back4app/ios-crud-to-do-list) ::: ## Goal To understand how objects are parsed and stored on a Back4App Database. ## Prerequisites :::hint{type="info"} **To complete this quickstart, you need:** - Xcode. - An app created at Back4App. - Follow the [New Parse App tutorial](https://www.back4app.com/docs/get-started/new-parse-app) to learn how to create a Parse app at Back4App. - **Note: **Follow the [Install Parse SDK (Swift) Tutorial](https://www.back4app.com/docs/ios/parse-swift-sdk) to create an Xcode Project connected to Back4App. ::: ## Understanding our Recipes App The app functionality is based on a form where one can enter information about a recipe. Depending on the information, the data type may vary. In our example the recipe has the following features: | Field | Data Type | Description | | ----------------------- | ----------------- | ----------------------------------------------------------------------------------------------- | | Name | String | Name of the recipe | | Servings | Int | Number of servings | | Available | Bool | Determines whether the recipe is available or not | | Category | Category | A custom enumeration which classifies a recipe in three categories: Breakfast, Lunch and Dinner | | Ingredients | \[Ingredients] | The set of ingredients enclosed in a customIngredient\*\* \*\*struct | | Side options | \[String] | Names of the additional options the recipe comes with | | Nutritional information | \[String\:String] | A dictionary containing information about the recipe’s nutritional content | | Release date | Date | A date showing when the recipe was available | Additionally, there are more data types which are used to implement Database functionality like relation between objects. These data types are not covered in this tutorial. ## Quick reference of commands we are going to use Given an object, say Recipe, if you want to save it on a Back4App Database, you have to first make this object to conform the ParseSwift protocol (available via the ParseSwift SDK). ```swift 1 import Foundation 2 import ParseSwift 3 4 struct Recipe: ParseObject { 5 /// Enumeration for the recipe category 6 enum Category: Int, CaseIterable, Codable { 7 case breakfast = 0, lunch = 1, dinner = 2 8 9 var title: String { 10 switch self { 11 case .breakfast: return "Breakfast" 12 case .lunch: return "Lunch" 13 case .dinner: return "Dinner" 14 } 15 } 16 } 17 18 ... 19 20 /// A *String* type property 21 var name: String? 22 23 /// An *Integer* type property 24 var servings: Int? 25 26 /// A *Double* (or *Float*) type property 27 var price: Double? 28 29 /// A *Boolean* type property 30 var isAvailable: Bool? 31 32 /// An *Enumeration* type property 33 var category: Category? 34 35 /// An array of *structs* 36 var ingredients: [Ingredient] 37 38 /// An array of *Strings* 39 var sideOptions: [String] 40 41 /// A dictionary property 42 var nutritionalInfo: [String: String] 43 44 /// A *Date* type property 45 var releaseDate: Date? 46 } ``` Before storing instances of this object in a Back4App Database, all its properties must conform the Codable and Hashable protocols. We make use of the following methods for managing these objects on the Back4App Database: :::CodeblockTabs Create ```swift //The procedure for reading and updating a Recipe object is similar since they rely on the save() method. How a Recipe is instantiated determines if we are creating or updating the object on the Back4App Database. When creating a new instance we use 1 var newRecipe: Recipe 2 3 // Setup newRecipe's properties 4 newRecipe.name = "My recipe's name" 5 newRecipe.servings = 4 6 newRecipe.price = 3.99 7 newRecipe.isAvailable = false 8 newRecipe.category = .breakfast 9 newRecipe.sideOptions = ["Juice"] 10 newRecipe.releaseDate = Date() 11 ... 12 13 // Saves newRecipe on your Back4App Database synchronously and returns the new saved Item. It throws and error if something went wrong. 14 let savedRecipe = try? savedRecipe.save() 15 16 // Saves savedRecipe on your Back4App Database asynchronously, and passes a Result object to the completion block to handle the save proccess. 17 savedRecipe.save { result in 18 // Handle the result to check the save was successfull or not 19 } ``` Update ```swift //And to update an existing instance, we have to provide the objectId value which identifies the the object on the Back4App Database. A satandard update can be implemented in the following way 1 let recipeToUpdate = Recipe(objectId: "OBJECT_ID") 2 3 // Update the properties you need 4 recipeToUpdate.name = "My updated recipe's name" 5 recipeToUpdate.servings = 5 6 recipeToUpdate.price = 5.99 7 recipeToUpdate.isAvailable = true 8 recipeToUpdate.category = .lunch 9 recipeToUpdate.sideOptions = ["Juice", "Coffee"] 10 recipeToUpdate.releaseDate = Date().addingTimeInterval(3600 * 24) 11 ... 12 13 // Save changes synchronousty 14 try? recipeToUpdate.save() 15 16 // Or save changes asynchronously 17 recipeToUpdate.save { result in 18 // handle the result 19 } ``` Read ```swift //For reading objects stored on your Back4App Database, Recipe now provides the query() static method which returns a Query. This query object can be constructed using one or more QueryConstraint objects in the following way 1 let query = Recipe.query() // A query to fetch all Recipe items on your Back4App Database. 2 let query = Recipe.query("name" == "Omelette") // A query to fetch all Recipe items with name "Omelette" on your Back4App Database. 3 let query = Recipe.query(["name" == "Omelette", "price" = 9.99]) // A query to fetch all Recipe items with name = "Omelette" and price = 9.99. 4 5 // Fetches the items synchronously or throws an error if found. 6 let fetchedRecipes = try? query.find() 7 8 // Fetches the items asynchronously and calls a completion block passing a result object containing the result of the operation. 9 query.find { result in 10 // Handle the result 11 } ``` Delete ```swift //Any deletion process is performed by calling the method delete() on the object to be deleted 1 var recipeToDelete: Recipe 2 3 // Delete recipeToDelete synchronously 4 try? recipeToDelete.delete() 5 6 // Delete recipeToDelete asynchronously 7 recipeToDelete.delete { result in 8 // Handle the result 9 } ``` ::: ## 1 - Create the Recipe App Template We start by creating a new XCode project. This this tutorial the project should look like this ![](https://api.archbee.com/api/optimize/yD3zCY-NNBBIfd0uqcfR5/uYHuakrS2iSPUtwmnURpp_image.png) :::hint{type="success"} At any time, you can access the complete Project via our GitHub repositories. - [iOS Example Repository](https://github.com/templates-back4app/ios-crud-to-do-list) ::: Go to Xcode, and find the SceneDelegate.swift file. In order to add a navigation bar on top of the app, we setup a UINavigationController as the root view controller in the following way ```swift 1 class SceneDelegate: UIResponder, UIWindowSceneDelegate { 2 3 var window: UIWindow? 4 5 func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) { 6 guard let scene = (scene as? UIWindowScene) else { return } 7 8 window = .init(windowScene: scene) 9 window?.rootViewController = UINavigationController(rootViewController: RecipesController()) 10 window?.makeKeyAndVisible() 11 12 // Additional logic 13 } 14 15 ... 16 } ``` The root view controller class (RecipesController) for the navigation controller is a subclass of UIViewController in which we will layout a form to create and update Recipe objects on the Back4App Database. ## 2 - Setup the Recipe object Objects you want to save on your Back4App Database have to conform the ParseObject protocol. On our Recipes app this object is Recipe. Therefore, you first need to create this object. Create a new file Recipe.swift and add the following ```swift 1 import Foundation 2 import ParseSwift 3 4 struct Recipe: ParseObject { 5 /// Enumeration for the recipe category 6 enum Category: Int, CaseIterable, Codable { 7 case breakfast = 0, lunch = 1, dinner = 2 8 9 var title: String { 10 switch self { 11 case .breakfast: return "Breakfast" 12 case .lunch: return "Lunch" 13 case .dinner: return "Dinner" 14 } 15 } 16 } 17 18 // Required properties from ParseObject protocol 19 var objectId: String? 20 var createdAt: Date? 21 var updatedAt: Date? 22 var ACL: ParseACL? 23 24 /// A *String* type property 25 var name: String? 26 27 /// An *Integer* type property 28 var servings: Int? 29 30 /// A *Double* (or *Float*) type property 31 var price: Double? 32 33 /// A *Boolean* type property 34 var isAvailable: Bool? 35 36 /// An *Enumeration* type property 37 var category: Category? 38 39 /// An array of *structs* 40 var ingredients: [Ingredient] 41 42 /// An array of *Strings* 43 var sideOptions: [String] 44 45 /// A dictionary property 46 var nutritionalInfo: [String: String] 47 48 /// A *Date* type property 49 var releaseDate: Date? 50 51 /// Maps the nutritionalInfo property into an array of tuples 52 func nutritionalInfoArray() -> [(name: String, value: String)] { 53 return nutritionalInfo.map { ($0.key, $0.value) } 54 } 55 } ``` where we already added all the necessary properties to Recipe according to the recipes’s features table. The Ingredient data type is a struct holding the quantity and the description of the ingredient. As mentioned before, this data type should conform the Codable and Hashable protocols to be part of Recipe’s properties ```swift 1 import Foundation 2 3 struct Ingredient: Hashable, Codable { 4 var quantity: Float 5 var description: String 6 } ``` Additionally, the property category in Recipe has an enumeration (Category) as data type which also conforms the corresponding protocols ```swift 1 struct Recipe: ParseObject { 2 /// Enumeration for the recipe category 3 enum Category: Int, CaseIterable, Codable { 4 case breakfast = 0, lunch = 1, dinner = 2 5 6 ... 7 } 8 ... 9 } ``` ## 3 - Setting up RecipesController In RecipesController we should implement all the necessary configuration for the navigationBar and the form used to capture all the Recipe properties. This tutorial does not cover how to implement the layout for the form. We then focus on the logic related with managing data types using ParseSwift SDK. Below we highlight the key points in RecipesController which allow us to understand how we implement the connection between the user interface and the data coming from your Back4App Database ```swift 1 class RecipesController: UIViewController { 2 enum PreviousNext: Int { case previous = 0, next = 1 } 3 4 ... 5 6 var recipes: [Recipe] = [] // 1: An array of recipes fetched from your Back4App Database 7 8 // Section header labels 9 private let recipeLabel: UILabel = .titleLabel(title: "Recipe overview") 10 private let ingredientsLabel: UILabel = .titleLabel(title: "Ingredients") 11 private let nutritionalInfoLabel: UILabel = .titleLabel(title: "Nutritional information") 12 13 // 2: A custom view containing input fields to enter the recipe's information (except nutritional info. and ingredients) 14 let recipeOverviewView: RecipeInfoView 15 16 // 3: A stack view containig the fields to enter the recipe's ingredients 17 let ingredientsStackView: UIStackView 18 19 // 4: A stack view containig the fields to enter the nutritional information 20 let nutritionalInfoStackView: UIStackView 21 22 // 5: Buttons to handle the CRUD logic for the Recipe object currently displayed 23 private var saveButton: UIButton = UIButton(title: "Save") 24 private var updateButton: UIButton = UIButton(title: "Update") 25 private var reloadButton: UIButton = UIButton(title: "Reload") 26 27 var currentRecipeIndex: Int? // 6: An integer containing the index of the current recipe presenten from the recipes property 28 29 override func viewDidLoad() { 30 super.viewDidLoad() 31 setupNavigationBar() 32 setupViews() 33 } 34 35 override func viewDidAppear(_ animated: Bool) { 36 super.viewDidAppear(animated) 37 handleReloadRecipes() 38 } 39 40 private func setupNavigationBar() { 41 navigationController?.navigationBar.barTintColor = .primary 42 navigationController?.navigationBar.titleTextAttributes = [.foregroundColor: UIColor.white] 43 navigationController?.navigationBar.isTranslucent = false 44 navigationController?.navigationBar.barStyle = .black 45 navigationItem.title = "Parse data types".uppercased() 46 } 47 48 private func setupViews() { 49 ... // See the project example for more details 50 51 saveButton.addTarget(self, action: #selector(handleSaveRecipe), for: .touchUpInside) 52 updateButton.addTarget(self, action: #selector(handleUpdateRecipe), for: .touchUpInside) 53 reloadButton.addTarget(self, action: #selector(handleReloadRecipes), for: .touchUpInside) 54 } 55 56 ... 57 } ``` ## 3 - Handling user input and parsing a Recipe object In a separate file (called RecipesController+ParseSwiftLogic.swift), using an extension we now implement the methods handleSaveRecipe(), handleUpdateRecipe() and handleUpdateRecipe() to handle the input data ```swift 1 import UIKit 2 import ParseSwift 3 4 extension RecipesController { 5 /// Retrieves all the recipes stored on your Back4App Database 6 @objc func handleReloadRecipes() { 7 view.endEditing(true) 8 let query = Recipe.query() 9 query.find { [weak self] result in // Retrieves all the recipes stored on your Back4App Database and refreshes the UI acordingly 10 guard let self = self else { return } 11 switch result { 12 case .success(let recipes): 13 self.recipes = recipes 14 self.currentRecipeIndex = recipes.isEmpty ? nil : 0 15 self.setupRecipeNavigation() 16 17 DispatchQueue.main.async { self.presentCurrentRecipe() } 18 case .failure(let error): 19 DispatchQueue.main.async { self.showAlert(title: "Error", message: error.message) } 20 } 21 } 22 } 23 24 /// Called when the user wants to update the information of the currently displayed recipe 25 @objc func handleUpdateRecipe() { 26 view.endEditing(true) 27 guard let recipe = prepareRecipeMetadata(), recipe.objectId != nil else { // Prepares the Recipe object for updating 28 return showAlert(title: "Error", message: "Recipe not found.") 29 } 30 31 recipe.save { [weak self] result in 32 switch result { 33 case .success(let newRecipe): 34 self?.recipes.append(newRecipe) 35 self?.showAlert(title: "Success", message: "Recipe saved on your Back4App Database! (objectId: \(newRecipe.id)") 36 case .failure(let error): 37 self?.showAlert(title: "Error", message: "Failedto save recipe: \(error.message)") 38 } 39 } 40 } 41 42 /// Saves the currently displayed recipe on your Back4App Database 43 @objc func handleSaveRecipe() { 44 view.endEditing(true) 45 guard var recipe = prepareRecipeMetadata() else { // Prepares the Recipe object for storing 46 return showAlert(title: "Error", message: "Failed to retrieve all the recipe fields.") 47 } 48 49 recipe.objectId = nil // When saving a Recipe object, we ensure it will be a new instance of it. 50 recipe.save { [weak self] result in 51 switch result { 52 case .success(let newRecipe): 53 if let index = self?.currentRecipeIndex { self?.recipes[index] = newRecipe } 54 self?.showAlert(title: "Success", message: "Recipe saved on your Back4App Database! (objectId: \(newRecipe.id))") 55 case .failure(let error): 56 self?.showAlert(title: "Error", message: "Failed to save recipe: \(error.message)") 57 } 58 } 59 } 60 61 /// When called it refreshes the UI according to the content of *recipes* and *currentRecipeIndex* properties 62 private func presentCurrentRecipe() { 63 ... 64 } 65 66 /// Adds the 'Next recipe' and 'Previous recipe' button on the navigation bar. These are used to iterate over all the recipes retreived from your Back4App Database 67 private func setupRecipeNavigation() { 68 ... 69 } 70 71 /// Reads the information the user entered via the form and returns it as a *Recipe* object 72 private func prepareRecipeMetadata() -> Recipe? { 73 let ingredientsCount = ingredientsStackView.arrangedSubviews.count 74 let nutritionalInfoCount = nutritionalInfoStackView.arrangedSubviews.count 75 76 let ingredients: [Ingredient] = (0.. in case) to retrieve data, the query.find() method will parse all the data types and JSON objects to return a Recipe array, there is no additional parsing procedure to implement.