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Core Data

Dive deep into Core Data related topics, from basics to advanced implementations. Best practices explained with code examples.

How to observe NSManagedObject changes in Core Data using Combine

Observing changes in Core Data NSManagedObject instances with Combine publishers can be a great solution to keep your user interface ...
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  •  3 min read CombineCore Data

Data validation on insertion, update, and deletion in Core Data

Data validation in apps is important to make sure we save data conforming to the business rules. A name should ...
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  •  3 min read Core Data

Derived Attributes to improve Core Data Fetch Performance

Derived attributes are available since iOS 13 and aim to improve fetch performance in many different scenarios. Although we have ...
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  •  3 min read Core Data

Constraints in Core Data Entities explained

Constraints in Core Data are part of an entity configuration. Settings like the entity name and Spotlight display name might ...
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  •  4 min read Core DataSwift

NSManagedObject events: handling state in Core Data

An NSManagedObject lifecycle goes from insertion and updates until deletion in the end. All those events come with their own ...
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  •  4 min read Core DataSwift

How-to use Diffable Data Sources with Core Data

Diffable Data Sources were introduced at WWDC 2019 as a replacement for UICollectionViewDataSource and UITableViewDataSource. The API is available on ...
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  •  6 min read Core DataSwift

Persistent History Tracking in Core Data

WWDC 2017 introduced a new concept available from iOS 11 which is persistent history tracking. It's Apple's answer for merging ...
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  •  7 min read Core DataSwift

Write-Ahead Logging (WAL) disabled to force commits in Core Data

Write-Ahead Logging is the default journaling mode for Core Data SQLite stores since iOS 7 and OS X Mavericks. Journaling ...
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  •  4 min read Core DataSwift

ValueTransformer in Core Data explained: Storing absolute URLs

ValueTransformers in Core Data are a powerful way of transforming values before they get inserted into the database and before ...
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  •  7 min read Core DataSwift

Core Data Performance: 6 tips you should know

Writing Core Data code with performance in mind helps to prepare your app for the future. Your database might be ...
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  •  5 min read Core DataSwift

NSFetchedResultsController extension to observe relationship changes

Apple provides us with great classes like the NSFetchedResultsController to interact with Core Data databases in our apps. The API ...
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  •  8 min read Core DataSwift

Core Data and App extensions: Sharing a single database

Core Data got better and better over the years with improved APIs that make it easier to work with. The ...
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  •  5 min read Core DataSwift