Schema migration is also non-trivial, almost always requiring code. Unlike EOF, though, Core Data is not currently designed for multiuser or simultaneous access unless you use ODBC framework. If you have the Xcode Data Model file, you can read and write files in that format freely. Recently, Core Data store for ODBC has been made available in ODBC framework. Unlike EOF, it is not possible to write your own SQL, as the underlying store may not be SQL-based. This portion of Core Data is similar to the original Enterprise Objects Framework (EOF) system, in that one can write fairly sophisticated queries. Each method carries advantages and disadvantages, such as being human readable (XML) or more memory efficient (SQLite). With the release of Mac OS X 10.5 Leopard, developers can also create their own custom atomic store types. Connecting the Save menu item to the appropriate method in the controller object will direct the controller to examine the object stack, determine which objects are dirty, and then re-write a Core Data document file with these changes.Ĭore Data is organized into a large hierarchy of classes, though interaction is only prevalent with a small set of them.Ĭore Data can serialize objects into XML, binary, or SQLite for storage. From that point on the author's code manipulates these Core Data objects, rather than the underlying vCards. They could then write standard Objective-C or Swift code to read vCard files and put the data into Core Data managed entities. Using Core Data the developer would drag their schema from the data designer in Xcode into an interface builder window to create a GUI for their schema. In order to manage these, the author intends to read the vCards into objects, and then store them in a single larger XML file. When combined with Cocoa bindings the UI can display many components of the data model without needing background code.įor example: a developer might be writing a program to handle vCards. The controller objects available in Interface Builder can retrieve and manipulate these entities directly. Code can retrieve and manipulate this data on a purely object level without having to worry about the details of storage and retrieval. Among other tasks, it handles change management, serializing to disk, memory footprint minimization and queries against the data.Ĭore Data describes data with a high level data model expressed in terms of entities and their relationships plus fetch requests that retrieve entities meeting specific criteria. Just as Cocoa Bindings handle many of the duties of the controller in a model–view–controller design, Core Data handles many of the duties of the data model. Core Data interfaces directly with SQLite, insulating the developer from the underlying SQL. Core Data manages the serialized version, providing object lifecycle and object graph management, including persistence. The data can be manipulated using higher level objects representing entities and their relationships. It allows data organized by the relational entity–attribute model to be serialized into XML, binary, or SQLite stores. It was introduced in Mac OS X 10.4 Tiger and iOS with iPhone SDK 3.0. Apple Developer Core Data Programming GuideĬore Data is an object graph and persistence framework provided by Apple in the macOS and iOS operating systems.
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