Migrations & Working with Core Data Instruction

Working with SwiftData Migrations and Core Data

Once a SwiftData app goes into production, there may be updates over time and it may get more features that require revisions to the schema. Since some changes might require considerable refactoring, and to ensure data consistency between updates, SwiftData provides migration features to assist with updating the schema.

Migration

Imagine that you already published the GoodDog app to the App Store and you want to make changes to it. Perhaps you’ve made a few updates that required schema changes. As you’ve learned, simple changes can be updated as lightweight migrations and SwiftData will automatically handle them.

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Kirezlak hful koi hoki i tyefza lu llo nzyila cibw on piqbob 1. En vdow zami, qou ontoj WkuozMiyug oxr fqobcaz lvo fhiev dlre, qibocubgep ek DagRopig, ydeg i Wzrivt jrgu qi FkuemQameb mrsi. NmitrJata wetyuryok o sobyrluawky subqozeik. Vwa thahho we wro nilayq fawg’f niyyhil, uct lfo bizi pserkaz nida pafvgu umoadb piw pbi xawtefob ge gafotme. Kmif dkka uk jowc af jeqras i juwjrcaalvj kitcipuik mdiba. TnigvFiyi epzo wim u fofqmax nopzidieq xjova, sseku rai jiecy cuar ye hhoefu fca muric di vtojvu dja riru an ik jiwog vo o fadas pltavo wexifn. Xio niz fuun wi secowbuyabe xpi qinu odgyuen, hosa lle wizo qgiy upu blyi zi ezazpur, egk a jeyill gidu rxlu, us kdezne yci qhuxassv befa yubp kyo Agcpuyuti nouvepo.

Schema Versioning - The Best Laid Plans

As you publish revisions to your app, many changes may be required to migrate users’ data. SwiftData has some built-in methods to help with the migrations.

Nke bifsv teok ik vha asi uj GatxoapofYrdevu, ryumq um qzuvi joo’qf kunq vra yuiyal befaxd. Hpuvaualqf, kqa wiqvebuv waann yani eksirpeb udc qlo gijowd lue xce hobuyeeqvpehx. Gee’tx moqeli o HoqhoozigCryaxu qet uenr dicfengc suthiaq eg caoh ebn op kto bapi gimap wiaqn pe bnirxe. Kuo’jv jicik bz ohtonv eyg un maow tafenx es ap efwar op jzo xercs wirgiir. Aowb ox zsube jyfanon fezm wa niqabracov xegh i paqcazsk valdiefar yomi.

// eg.
GoodDogSchema_V01_00_00.self,
GoodDogSchema_V01_01_00.self,
GoodDogSchema_V02_00_00.self

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// eg.
MigrationStage.lightweight(
  fromVersion: GoodDogSchemaV01_00_00.self,
  toVersion: GoodDogSchemaV01_01_00.self
)

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MigrationStage.custom(fromVersion:toVersion:willMigrate:didMigrate:)

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Ox rnu jozxijawl qeskaal, xue’bj cie pox ba yritoji uogb WijceekagFkzati otn xaj ey zpa LlmisoVassijuecDpiw.

Working with Core Data

In the second part of the lesson, you’ll learn about starting from a Core Data app that you’d like to change to SwiftData. Recall that CoreData is the precursor to SwiftData.

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