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kishikawa katsumi
My SwiftData Review
SwiftDataͷධՁʹؔ͢Δࢲݟ
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What Is SwiftData?
SwiftDataͱʁ
• Introduced at WWDC 2023
• Data persistence framework
• Works great with SwiftUI
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Tech Event Manager Sample App
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Tech Event Manager Sample App
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Address Book Sample App
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Schema Definition
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Display the Data
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What Is SwiftData?
SwiftDataͱʁ
• Introduced at WWDC 2023
• Data persistence framework
• Works great with SwiftUI
• Core Data wrapper 🔑
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What Is SwiftData?
SwiftDataͱʁ
• Introduced at WWDC 2023
• Data persistence framework
• Works great with SwiftUI
• Core Data wrapper 🔑
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SwiftData Is Just Wrapper of Core Data
SwiftDataCore DataͷϥούʔϥΠϒϥϦͰ͋Δ
• Not reworked Core Data
• Provides a more user-friendly API for working with Core Data in Swift
• Schemas de
fi
ned in code
• No separate mapping
fi
le (*.xcdatamodeld)
• Type safe queries
• Eliminate string-based Key Paths
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SwiftData Simplifies the Core Data API
Core DataͷAPI͕ΑΓγϯϓϦʹ͍͘͢
• NSPersistentContainer => ModelContainer
• NSManagedObjectModel => PersistentModel
• NSManagedObjectContext => ModelContext
• NSPredicate => #Predicate
• NSPersistentStoreCoordinator => 🗑
• *.xcdatamodeld => 🗑
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Also brings legacy issues
طଘͷͦͷ··͍ͬͯΔ
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The issue is Core Data
݁ہͷͱ͜Ζɺ૪Core Data
• For those familiar with Core Data,
• Core Data is proven, stable, simple and convenient.
• For those unfamiliar with Core Data,
• Core Data is di
ffi
cult to control and is a black box
that causes mysterious errors and crashes.
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Why argue for and against Core Data?
ͳͥCore DataͷධՁ͕͔ΕΔͷ͔
• CoreData is not relational database
• However, many expect Core Data to be SQLite ORM
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Core Data Is Not Relational Database (Nor ORM)
Core DataRelational DatabaseͰͳ͍ʢORMͰͳ͍ʣ
• CoreData Is Object Graph Manager
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Misconception that CoreData is not RDB
CoreDataRDBͰͳ͍ͱ͍͏͜ͱͷޡղ
• Apple just says it for marketing purposes.
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Misconception that CoreData is not RDB
CoreDataRDBͰͳ͍ͱ͍͏͜ͱͷޡղ
• Apple just says it for marketing purposes.
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Misconception that CoreData is not RDB
CoreDataRDBͰͳ͍ͱ͍͏͜ͱͷޡղ
• Apple just says it for marketing purposes
• Support for data stores other than SQLite (Binary, XML, In-Memory)
• SwiftData supports SQLite only. Therefore, it is a wrapper for SQLite.
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Misconception that CoreData is not RDB
CoreDataRDBͰͳ͍ͱ͍͏͜ͱͷޡղ
• Apple just says it for marketing purposes
• Support for data stores other than SQLite (Binary, XML, In-Memory)
• SwiftData supports SQLite only. Therefore, it is a wrapper for SQLite.
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Misconception that CoreData is not RDB
CoreDataRDBͰͳ͍ͱ͍͏͜ͱͷޡղ
• Apple just says it for marketing purposes
• Support for data stores other than SQLite (Binary, XML, In-Memory)
• SwiftData supports SQLite only. Therefore, it is a wrapper for SQLite.
• Completely di
ff
erent, technically
• CoreData is object graph manager
• Object graph is groups of objects form a network through their relationships
with each other.
In short, it is a collection of objects.
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For Relational Database
Many to Many Relations
Event Attendee
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For Relational Database
Event Attendee
Event-Attendee
Many to Many Relations
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For Core Data
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For Core Data
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CoreData Is Not Relational Database
CoreData Is Object Graph Manager
• Many to Many relationships
• No foreign key required
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All Operations Are on Memory
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All Operations Are on Memory
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CoreData Is Not Relational Database
All Operations Are on Memory
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CoreData Is Not Relational Database
All Operations Are on Memory
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CoreData Is Not Relational Database
Batch Update
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CoreData Is Not Relational Database
Batch Update
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CoreData Is Not Relational Database
Batch Update
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CoreData Is Not Relational Database
Batch Update
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CoreData Is Not Relational Database
Batch Update
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CoreData Is Not Relational Database
Batch Update
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Available Data Types
อଘͰ͖ΔϓϩύςΟͷܕ
• Primitive Types
• Int, Float, Double, String, Bool
• URL, UUID
• Codable
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Codable
Composite Type (Core Data)
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Codable (Composite) Types Are Queryable
CodableܕͰอଘͨ͠σʔλΛݕࡧ݅ʹͰ͖Δ
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Codable (Composite) Types Are Queryable
CodableܕͰอଘͨ͠σʔλΛݕࡧ݅ʹͰ͖Δ
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Enums Cannot Be Stored Even If Codable
EnumCodableͰ͋ͬͯอଘͰ͖ͳ͍
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Available Data Types
อଘͰ͖ΔϓϩύςΟͷܕ
• Primitive Types
• Int, Float, Double, String, Bool
• ❌ CGFloat
• URL, UUID
• Codable
• ❌ Enums
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Auto Save Is Enabled, No Way to Detect Errors
Auto Save͕༗ޮͳͱ͖ɺอଘࣦഊΛΔ͕͢ͳ͍
• Seems to work correctly, but data is lost on exit
• Migration failures silently erase existing data
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Compiler Is Silent Despite Unsaved Models
อଘͰ͖ͳ͍σʔλϞσϧͰίϯύΠϧ͕௨Δ
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Compiler silent despite incomplete initialisers
ෆશͳΠχγϟϥΠβͰίϯύΠϧ͕௨Δ (Runtime Error)
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#Predicate Macro Has Many Unsupported Features
#PredicateϚΫϩະαϙʔτͷػೳ͕ଟ͍
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#Predicate Macro Has Many Unsupported Features
#PredicateϚΫϩະαϙʔτͷػೳ͕ଟ͍
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#Predicate Macro Has Many Unsupported Features
#PredicateϚΫϩະαϙʔτͷػೳ͕ଟ͍
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#Predicate Macro Has Many Unsupported Features
#PredicateϚΫϩະαϙʔτͷػೳ͕ଟ͍
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#Predicate Macro Has Many Unsupported Features
#PredicateϚΫϩະαϙʔτͷػೳ͕ଟ͍
• Case Insensitive Search
• Su
ffi
x Search
• Date formatting and Compare
• Max/Min
• Composite Unique Constraint
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Is SwiftData Production Ready?
SwiftData࣮༻Մೳ͔ʁ
• Depends on how familiar you are with Core Data.
• No Fine-Grained CoreData Controls
• No Faulting
• No Parent/Child Context
• No Merge Policy
• SwiftData Itself Is Also Incomplete
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Conclusion
݁
• SwiftDataͷ࠾༻৻ॏΛཁ͢Δ
• Core Dataͷܦݧ͕ඞཁ
• ORMΛٻΊ͍ͯΔͳΒORMΛ୳ͦ͏
• ແ੍ݶʹϢʔβʔ͕σʔλΛ࡞͢ΔΑ͏ͳ༻్ʹ͔ͳ͍
• ͍ͭͰσʔλΛফͤΔΩϟογϡͳͲͰࢼͦ͏
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