Swift大量自定义类数据持久化存储方案咨询：能否用UserDefaults？

Short answer: No, don't use UserDefaults for this scenario. UserDefaults is built for small, simple preference data—think user settings, UI state, or tiny app configurations. Storing 30 teams × 25 players (750 total players) with multiple attributes each will cause major issues:

• The entire UserDefaults plist loads into memory on app launch, wasting RAM and slowing down startup.
• Serializing/deserializing large complex objects (your Team/Player classes) will be slow and prone to errors.
• There’s no way to query specific data—you’d have to load every single team and player into memory just to access one player’s stats.

Here are the best options for your use case, ordered by how well they fit your needs:

1. Core Data #

Apple’s native persistent framework is tailor-made for your relational data (teams have many players). Here’s why it works:

• Define Team and Player entities with attributes (like name, appearances, goals) and set up a one-to-many relationship between them.
• Use fetch requests to load only the data you need (e.g., "get all players on Team X with >10 goals") instead of loading everything at once.
• Supports lazy loading, automatic schema migrations, and integrates seamlessly with SwiftUI/UIKit.
• Pros: Built-in (no third-party dependencies), robust for relational data, memory-efficient.
• Cons: Has a learning curve if you’re new to it—you’ll need to wrap your head around managed object contexts, fetch requests, and migrations.

2. Realm (MongoDB Realm) #

A popular object-oriented database that lets you work directly with your custom classes (no entity mapping required). It’s a great alternative to Core Data if you want something easier to set up:

• Define your Team and Player classes as Object subclasses (Realm’s base class) and add properties directly.
• Queries are intuitive (e.g., realm.objects(Player.self).filter("goals > 10")).
• Fast performance, with built-in support for real-time sync if you ever want to add cloud features later.
• Pros: Minimal setup, object-oriented API, fast queries, excellent documentation.
• Cons: Third-party dependency (though it’s well-maintained), some advanced Core Data features might not be available.

3. GRDB (SQLite Wrapper) #

If you’re comfortable with SQL or want full control over your database, GRDB is a Swift-friendly wrapper around SQLite:

• You can define your models as plain Swift structs and use GRDB to map them to SQLite tables.
• Write raw SQL queries or use GRDB’s query builder to fetch data efficiently.
• Lightweight, fast, and gives you low-level control over your data.
• Pros: Full control, no heavy framework overhead, widely used.
• Cons: Requires manual mapping between objects and database rows, you’ll have to handle migrations yourself.

4. File-Based Storage (JSON/Plist) #

If you want a simple solution without learning a new framework, you could serialize your data to JSON or plist files and save them to the app’s Documents directory using Codable:

• Make your Team and Player classes conform to Codable, then convert them to data with JSONEncoder and save to a file.
• Pros: Simple to implement if you already know Codable, no extra dependencies.
• Cons: You have to load the entire file into memory to access any data (inefficient for large datasets). No built-in querying—you’ll have to filter data in memory after loading it.

For your football manager app, Core Data or Realm are the top choices. Both handle relational data efficiently, let you fetch only what you need, and manage memory well. Core Data is ideal if you want to stick with Apple’s native tools, while Realm is better if you prefer a simpler, object-oriented API without Core Data’s learning curve.

内容的提问来源于stack exchange，提问作者Tarjerw