Core Data
Essence
Core Data is Apple's framework for managing a model's object graph and persisting it to disk. It is neither a database nor an ORM in the classic sense: you work with objects (NSManagedObject), their attributes and relationships, and Core Data handles change tracking, lazy loading (faulting), undo/redo, validation, schema migrations and, optionally, CloudKit sync. The store is most often SQLite, but that's an implementation detail: a binary or in-memory store works too.
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