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WWDC23 · 9 min · Essentials / Swift

Meet SwiftData

SwiftData is a powerful and expressive persistence framework built for Swift. We’ll show you how you can model your data directly from Swift code, use SwiftData to work with your models, and integrate with SwiftUI.

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Code shown on screen · 10 snippets

Adding @Model to Trip swift · at 1:27 ↗ 
import SwiftData

@Model
class Trip {
    var name: String
    var destination: String
    var endDate: Date
    var startDate: Date
 
    var bucketList: [BucketListItem]? = []
    var livingAccommodation: LivingAccommodation?
}
Providing options for @Attribute and @Relationship swift · at 2:46 ↗ 
@Model
class Trip {
    @Attribute(.unique) var name: String
    var destination: String
    var endDate: Date
    var startDate: Date
 
    @Relationship(.cascade) var bucketList: [BucketListItem]? = []
    var livingAccommodation: LivingAccommodation?
}
Initialize a ModelContainer swift · at 3:43 ↗ 
// Initialize with only a schema
let container = try ModelContainer([Trip.self, LivingAccommodation.self])

// Initialize with configurations
let container = try ModelContainer(
    for: [Trip.self, LivingAccommodation.self],
    configurations: ModelConfiguration(url: URL("path"))
)
Creating a model container in SwiftUI swift · at 3:58 ↗ 
import SwiftUI

@main
struct TripsApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .modelContainer(
            for: [Trip.self, LivingAccommodation.self]
        )
    }
}
Accessing the environment's ModelContext swift · at 4:20 ↗ 
import SwiftUI

struct ContextView : View {
    @Environment(\.modelContext) private var context
}
Building a predicate swift · at 5:13 ↗ 
let today = Date()
let tripPredicate = #Predicate<Trip> { 
    $0.destination == "New York" &&
    $0.name.contains("birthday") &&
    $0.startDate > today
}
Fetching with a FetchDescriptor swift · at 5:32 ↗ 
let descriptor = FetchDescriptor<Trip>(predicate: tripPredicate)

let trips = try context.fetch(descriptor)
Fetching with fetch and sort descriptors swift · at 5:46 ↗ 
let descriptor = FetchDescriptor<Trip>(
    sortBy: SortDescriptor(\Trip.name),
    predicate: tripPredicate
)

let trips = try context.fetch(descriptor)
Working with a ModelContext swift · at 6:15 ↗ 
var myTrip = Trip(name: "Birthday Trip", destination: "New York")

// Insert a new trip
context.insert(myTrip)

// Delete an existing trip
context.delete(myTrip)

// Manually save changes to the context
try context.save()
Using @Query in SwiftUI swift · at 7:38 ↗ 
import SwiftUI

struct ContentView: View  {
    @Query(sort: \.startDate, order: .reverse) var trips: [Trip]
    @Environment(\.modelContext) var modelContext
    
    var body: some View {
       NavigationStack() {
          List {
             ForEach(trips) { trip in 
                 // ...
             }
          }
       }
    }
}

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