Why are SwiftData models created as classes? 관련

SwiftData by Example

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Why are SwiftData models created as classes? | SwiftData by Example

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Why are SwiftData models created as classes?

Updated for Xcode 15

Swift developers love using structs, but SwiftData uses classes intentionally:

1. They allow us to share SwiftData objects in many places, so that when we make a change in one place that change appears everywhere else the data is used. This is the same reason why ObservableObject and @Observable types also rely on classes.
2. Using a class allows a model to create a relationship to another instance of itself. For example, we might say that each employee in a company has a manager, who is also an employee.

As a result, the @Model macro can be used only on classes.

That being said, you can integrate structs into your models if you want, as long as the structs conform to Codable. For example, you might say this:

@Model
class Customer {
    var name: String
    var address: Address

    init(name: String, address: Address) {
        self.name = name
        self.address = address
    }
}

struct Address: Codable {
    var line1: String
    var line2: String
    var city: String
    var postCode: String
}

This can be a neat way of breaking your data models up into more manageable parts, although for most relationships I would recommend using @Model classes across the board because it allows you to query your data more broadly.