SwiftData - get next record

I have a basic, test database in SwiftData that just consists of a number and a name. The number is an ascending integer and mainly continuous, but that can't be a given.

Displaying the data in a list works fine. E.g.:

@Query(sort: \EntrantsDatabase.number) var entrants: [EntrantsDatabase]
    @State private var entrantToEdit: EntrantsDatabase?
    var body: some View {
        List {
            ForEach(entrants) { entrant in
                EntrantCell(entrant: entrant) 

But next I want to display just one record/row at a time , click a button and then move onto the next.

I have tried to set the fetchLimit to 1:

@Query(sort: \EntrantsDatabase.number) var entrants: [EntrantsDatabase]
 
init() {
        var fetchDescriptor = FetchDescriptor<EntrantsDatabase>(sortBy: [SortDescriptor(\EntrantsDatabase.number, order: .reverse)])
        fetchDescriptor.propertiesToFetch = [\.number, \.name]
        fetchDescriptor.fetchLimit = 1
        
 }

But then in in the view how would I display the result and then go onto the next record?

var body: some View {
        VStack {
            HStack {
                     Text(entrants.name)

This doesn't work.

You could try this approach using an additional var numbers: [Int] that stores the unique numbers of @Query(...) var entrants. Sort those numbers in .onAppear and use an nextIndex into this array of possible numbers in the Button.

Example code:

 struct ContentView: View {
     @Environment(\.modelContext) private var modelContext
     @Query(sort: \EntrantsDatabase.number) var entrants: [EntrantsDatabase]

     @State private var nextEntrant: EntrantsDatabase?
     @State private var numbers: [Int] = []
     @State private var nextIndex: Int = -1
     
     var body: some View {
         VStack {
             List {
                 ForEach(entrants) { entrant in
                     HStack {
                         Text(entrant.name)
                         Text("\(entrant.number)")
                     }
                 }
                 Spacer()
                 // select the next nextEntrant number to be displayed
                 Button("Next") {
                     nextIndex += 1
                     if nextIndex < numbers.count, let next = entrants.first(where: { $0.number == numbers[nextIndex] }) {
                         nextEntrant = next
                     }
                 }.buttonStyle(.borderedProminent)
                 Spacer()
                 // display the nextEntrant
                 if let nextOne = nextEntrant {
                     HStack {
                         Text(nextOne.name)
                         Text("\(nextOne.number)")
                     }
                 }
             }
             .padding()
             .onAppear {
//                 // for my testing
//                 if !entrants.isEmpty { return }
//                 let newItem1 = EntrantsDatabase(name: "New Entrant1", number: 1)
//                 modelContext.insert(newItem1)
//                 let newItem2 = EntrantsDatabase(name: "New Entrant2", number: 2)
//                 modelContext.insert(newItem2)
//                 let newItem4 = EntrantsDatabase(name: "New Entrant4", number: 4)
//                 modelContext.insert(newItem4)
//                 let newItem5 = EntrantsDatabase(name: "New Entrant5", number: 5)
//                 modelContext.insert(newItem5)
//                 try? modelContext.save()
                 
                 // make sure all numbers are unique and sorted
                 var numberSet: Set<Int> = []
                 numberSet.formUnion(entrants.map(\.self.number))
                 numbers = Array(numberSet).sorted()
             }
         }
     }
 }

@Model final class EntrantsDatabase {
    var name: String
    var number: Int
    
    init(name: String, number: Int) {
        self.name = name
        self.number = number
    }
}

EDIT-1:

@Query(...) gives you all the records as an array [EntrantsDatabase]. You can go through the index of that array and use that if you want to simply display the next record, instead of the next number.

For example:

struct ContentView: View {
    @Environment(\.modelContext) private var modelContext
    @Query(sort: \EntrantsDatabase.number) var entrants: [EntrantsDatabase]
    
    @State private var nextIndex: Int = -1
    
    var body: some View {
        VStack {
            List {
                ForEach(entrants) { entrant in
                    HStack {
                        Text(entrant.name)
                        Text("\(entrant.number)")
                    }
                }
                Spacer()
                Button("Next") {
                    nextIndex += 1
                }.buttonStyle(.borderedProminent)
                Spacer()
                if nextIndex < entrants.count && nextIndex != -1 {
                    HStack {
                        Text(entrants[nextIndex].name)
                        Text("\(entrants[nextIndex].number)")
                    }
                } else {
                    Text("no selection")
                        .onAppear {
                            nextIndex = -1
                        }
                }
            }
            .padding()
        }
    }
}