RKEntityIdentifier Class Reference
| Inherits from | NSObject |
| Declared in | RKEntityIdentifier.h |
Overview
The RKEntityIdentifier object describes a means for uniquely identifying one or more NSManagedObject objects within a Core Data managed object model. Entity identifiers are used by RestKit to identify existing managed objects that are to be updated while performing object mapping with an RKEntityMapping object. Entity identifiers identify objects by specifying the attributes that can be used to uniquely differentiate managed objects within a context.
Tasks
Initializing an Entity Identifier
-
+ identifierWithEntityName:attributes:inManagedObjectStore:Creates and returns a new entity identifier with the entity for the given name and attributes in the specified managed object store.
-
– initWithEntity:attributes:Initializes the receiver with a given entity and array of attributes.
Accessing Entity Identity
-
entityThe entity that the receiver identifies.
property -
attributesAn array of
propertyNSAttributeDescriptionobjects specifying the attributes used for identification.
Filtering the Identified Objects
-
predicateAn optional predicate for filtering identified objects.
property
Inferring Identifiers from the Model
-
+ inferredIdentifierForEntity:Creates and returns an entity identifier for the given entity inferred from the managed object model.
Properties
attributes
An array of NSAttributeDescription objects specifying the attributes used for identification.
@property (nonatomic, copy, readonly) NSArray *attributesDeclared In
RKEntityIdentifier.hClass Methods
identifierWithEntityName:attributes:inManagedObjectStore:
Creates and returns a new entity identifier with the entity for the given name and attributes in the specified managed object store.
+ (id)identifierWithEntityName:(NSString *)entityName attributes:(NSArray *)attributes inManagedObjectStore:(RKManagedObjectStore *)managedObjectStoreParameters
- entityName
The name of the entity being identified.
- attributes
An array of
NSStringobjects containing the names of attributes orNSAttributeDescriptionobjects specifying the identifying attributes for the entity.
- managedObjectStore
The managed object store containing the managed object model within which the entity exists.
Return Value
A new entity identifier, configured with the given entity for the given name and the array of attributes.
Declared In
RKEntityIdentifier.hinferredIdentifierForEntity:
Creates and returns an entity identifier for the given entity inferred from the managed object model.
+ (RKEntityIdentifier *)inferredIdentifierForEntity:(NSEntityDescription *)entityParameters
- entity
The entity to infer an identifier for.
Return Value
An entity identifier inferred from the model for the given entity, or nil if none could be inferred.
Discussion
When inferring an entity identifier, the entity is first checked for a user info key specifying the identifying attributes. If the user info of the given entity contains a value for the key ‘RKEntityIdentifierAttributes’, then that value is used to construct an entity identifier. The user info key must contain a string or an array of strings specifying the names of attributes that exist in the given entity.
If no attributes are specified in the user info, then the entity is searched for an attribute whose name matches the llama-cased name of the entity. For example, an entity named ‘Article’ would have an inferred identifier attribute of ‘articleID’ and an entity named ‘ApprovedComment’ would be inferred as ‘approvedCommentID’. If such an attribute is found within the entity, an identifier is returned specifying that attribute. If none is returned, the the attributes are search for the following names:
- ‘identifier’
- ‘ID’
- ‘URL’
- ‘url’
If any of these attributes are found, then an entity identifier is created for that attribute. If all possible inferred attributes are exhausted, then nil is returned.
Declared In
RKEntityIdentifier.hInstance Methods
initWithEntity:attributes:
Initializes the receiver with a given entity and array of attributes.
- (id)initWithEntity:(NSEntityDescription *)entity attributes:(NSArray *)attributesParameters
- entity
The entity being identified.
- attributes
An array of
NSStringobjects containing the names of attributes orNSAttributeDescriptionobjects specifying the identifying attributes for the entity.
Return Value
The receiver, initialized with the given entity and attributes.
Declared In
RKEntityIdentifier.h