Compared to Core Data, SwiftData has fundamentally revolutionized the way data models are constructed. It not only supports a purely code-based declaration method but also allows the direct use of types conforming to the Codable protocol and enum types within models, which are its significant new features. Many developers are inclined to leverage these new capabilities because they seem to fit very well with the Swift language’s declaration style. However, a lack of understanding of the implementation details and potential limitations of these new features may lead to various issues in the future. This article aims to discuss several key points to consider when using Codable and enums in SwiftData models, helping developers avoid common pitfalls.