Classes

The following classes are available globally.

  • RLMArray is the container type in Realm used to define to-many relationships.

    Unlike an NSArray, RLMArrays hold a single type, specified by the objectClassName property. This is referred to in these docs as the “type” of the array.

    When declaring an RLMArray property, the type must be marked as conforming to a protocol by the same name as the objects it should contain (see the RLM_ARRAY_TYPE macro). In addition, the property can be declared using Objective-C generics for better compile-time type safety.

    RLM_ARRAY_TYPE(ObjectType)
...
@property RLMArray<ObjectType *><ObjectType> *arrayOfObjectTypes;

    RLMArrays can be queried with the same predicates as RLMObject and RLMResults.

    RLMArrays cannot be created directly. RLMArray properties on RLMObjects are lazily created when accessed, or can be obtained by querying a Realm.

    Key-Value Observing

    RLMArray supports array key-value observing on RLMArray properties on RLMObject subclasses, and the invalidated property on RLMArray instances themselves is key-value observing compliant when the RLMArray is attached to a managed RLMObject (RLMArrays on unmanaged RLMObjects will never become invalidated).

    Because RLMArrays are attached to the object which they are a property of, they do not require using the mutable collection proxy objects from -mutableArrayValueForKey: or KVC-compatible mutation methods on the containing object. Instead, you can call the mutation methods on the RLMArray directly.

    See more

    Declaration

    Objective-C

    @interface RLMArray <RLMObjectType : RLMObject *> : NSObject<RLMCollection,NSFastEnumeration>

    Swift

    class RLMArray
    Show on GitHub

  • An RLMSortDescriptor stores a property name and a sort order for use with sortedResultsUsingDescriptors:. It is similar to NSSortDescriptor, but supports only the subset of functionality which can be efficiently run by Realm’s query engine.

    RLMSortDescriptor instances are immutable.

    See more

    Declaration

    Objective-C

    @interface RLMSortDescriptor : NSObject

    Swift

    class RLMSortDescriptor : NSObject
    Show on GitHub

  • A RLMCollectionChange object encapsulates information about changes to collections that are reported by Realm notifications.

    RLMCollectionChange is passed to the notification blocks registered with -addNotificationBlock on RLMArray and RLMResults, and reports what rows in the collection changed since the last time the notification block was called.

    The change information is available in two formats: a simple array of row indices in the collection for each type of change, and an array of index paths in a requested section suitable for passing directly to UITableView’s batch update methods. A complete example of updating a UITableView named tv:

    [tv beginUpdates];
[tv deleteRowsAtIndexPaths:[changes deletionsInSection:0] withRowAnimation:UITableViewRowAnimationAutomatic];
[tv insertRowsAtIndexPaths:[changes insertionsInSection:0] withRowAnimation:UITableViewRowAnimationAutomatic];
[tv reloadRowsAtIndexPaths:[changes modificationsInSection:0] withRowAnimation:UITableViewRowAnimationAutomatic];
[tv endUpdates];

    All of the arrays in an RLMCollectionChange are always sorted in ascending order.

    See more

    Declaration

    Objective-C

    @interface RLMCollectionChange : NSObject

    Swift

    class RLMCollectionChange : NSObject
    Show on GitHub

  • RLMMigration instances encapsulate information intended to facilitate a schema migration.

    A RLMMigration instance is passed into a user-defined RLMMigrationBlock block when updating the version of a Realm. This instance provides access to the old and new database schemas, the objects in the Realm, and provides functionality for modifying the Realm during the migration.

    See more

    Declaration

    Objective-C

    @interface RLMMigration : NSObject

    Swift

    class RLMMigration : NSObject
    Show on GitHub

  • RLMObject is a base class for model objects representing data stored in Realms.

    Define your model classes by subclassing RLMObject and adding properties to be managed. Then instantiate and use your custom subclasses instead of using the RLMObject class directly.

    // Dog.h
@interface Dog : RLMObject
@property NSString *name;
@property BOOL      adopted;
@end

// Dog.m
@implementation Dog
@end //none needed

    Supported property types

    • NSString
    • NSInteger, int, long, float, and double
    • BOOL or bool
    • NSDate
    • NSData
    • NSNumber<X>, where X is one of RLMInt, RLMFloat, RLMDouble or RLMBool, for optional number properties
    • RLMObject subclasses, to model many-to-one relationships.
    • RLMArray<X>, where X is an RLMObject subclass, to model many-to-many relationships.

    Querying

    You can initiate queries directly via the class methods: allObjects, objectsWhere:, and objectsWithPredicate:. These methods allow you to easily query a custom subclass for instances of that class in the default Realm.

    To search in a Realm other than the default Realm, use the allObjectsInRealm:, objectsInRealm:where:, and objectsInRealm:withPredicate: class methods.

    See

    RLMRealm

    Relationships

    See our Cocoa guide for more details.

    Key-Value Observing

    All RLMObject properties (including properties you create in subclasses) are Key-Value Observing compliant, except for realm and objectSchema.

    Keep the following tips in mind when observing Realm objects:

    1. Unlike NSMutableArray properties, RLMArray properties do not require using the proxy object returned from -mutableArrayValueForKey:, or defining KVC mutation methods on the containing class. You can simply call methods on the RLMArray directly; any changes will be automatically observed by the containing object.
    2. Unmanaged RLMObject instances cannot be added to a Realm while they have any observed properties.
    3. Modifying managed RLMObjects within -observeValueForKeyPath:ofObject:change:context: is not recommended. Properties may change even when the Realm is not in a write transaction (for example, when -[RLMRealm refresh] is called after changes are made on a different thread), and notifications sent prior to the change being applied (when NSKeyValueObservingOptionPrior is used) may be sent at times when you cannot begin a write transaction.
    See more

    Declaration

    Objective-C

    @interface RLMObject : RLMObjectBase <RLMThreadConfined>

    Swift

    class RLMObject
    Show on GitHub

  • This class represents Realm model object schemas.

    When using Realm, RLMObjectSchema instances allow performing migrations and introspecting the database’s schema.

    Object schemas map to tables in the core database.

    See more

    Declaration

    Objective-C

    @interface RLMObjectSchema : NSObject <NSCopying>

    Swift

    class RLMObjectSchema : NSObject, NSCopying
    Show on GitHub

  • RLMProperty instances represent properties managed by a Realm in the context of an object schema. Such properties may be persisted to a Realm file or computed from other data from the Realm.

    When using Realm, RLMProperty instances allow performing migrations and introspecting the database’s schema.

    These property instances map to columns in the core database.

    See more

    Declaration

    Objective-C

    @interface RLMProperty : NSObject

    Swift

    class RLMProperty : NSObject
    Show on GitHub

  • An RLMPropertyDescriptor instance represents a specific property on a given class.

    See more

    Declaration

    Objective-C

    @interface RLMPropertyDescriptor : NSObject

    Swift

    class RLMPropertyDescriptor : NSObject
    Show on GitHub

  • An RLMRealmConfiguration instance describes the different options used to create an instance of a Realm.

    RLMRealmConfiguration instances are just plain NSObjects. Unlike RLMRealms and RLMObjects, they can be freely shared between threads as long as you do not mutate them.

    Creating configuration objects for class subsets (by setting the objectClasses property) can be expensive. Because of this, you will normally want to cache and reuse a single configuration object for each distinct configuration rather than creating a new object each time you open a Realm.

    See more

    Declaration

    Objective-C

    @interface RLMRealmConfiguration : NSObject <NSCopying>

    Swift

    class RLMRealmConfiguration : NSObject, NSCopying
    Show on GitHub

  • RLMResults is an auto-updating container type in Realm returned from object queries. It represents the results of the query in the form of a collection of objects.

    RLMResults can be queried using the same predicates as RLMObject and RLMArray, and you can chain queries to further filter results.

    RLMResults always reflect the current state of the Realm on the current thread, including during write transactions on the current thread. The one exception to this is when using for...in fast enumeration, which will always enumerate over the objects which matched the query when the enumeration is begun, even if some of them are deleted or modified to be excluded by the filter during the enumeration.

    RLMResults are lazily evaluated the first time they are accessed; they only run queries when the result of the query is requested. This means that chaining several temporary RLMResults to sort and filter your data does not perform any extra work processing the intermediate state.

    Once the results have been evaluated or a notification block has been added, the results are eagerly kept up-to-date, with the work done to keep them up-to-date done on a background thread whenever possible.

    RLMResults cannot be directly instantiated.

    See more

    Declaration

    Objective-C

    @interface RLMResults <RLMObjectType : RLMObject *> : NSObject<RLMCollection,NSFastEnumeration>

    Swift

    class RLMResults
    Show on GitHub

  • RLMLinkingObjects is an auto-updating container type. It represents a collection of objects that link to its parent object.

    For more information, please see the Inverse Relationships section in the documentation.

    Declaration

    Objective-C

    @interface RLMLinkingObjects <RLMObjectType : RLMObject *> : RLMResults

    Swift

    class RLMLinkingObjects
    Show on GitHub

  • RLMSchema instances represent collections of model object schemas managed by a Realm.

    When using Realm, RLMSchema instances allow performing migrations and introspecting the database’s schema.

    Schemas map to collections of tables in the core database.

    See more

    Declaration

    Objective-C

    @interface RLMSchema : NSObject <NSCopying>

    Swift

    class RLMSchema : NSObject, NSCopying
    Show on GitHub

  • A configuration object representing configuration state for a Realm which is intended to sync with a Realm Object Server.

    See more

    Declaration

    Objective-C

    @interface RLMSyncConfiguration : NSObject

    Swift

    class RLMSyncConfiguration : NSObject
    Show on GitHub

  • Opaque credentials representing a specific Realm Object Server user.

    See more

    Declaration

    Objective-C

    @interface RLMSyncCredentials : NSObject

    Swift

    class RLMSyncCredentials : NSObject
    Show on GitHub

  • A singleton manager which serves as a central point for sync-related configuration.

    See more

    Declaration

    Objective-C

    @interface RLMSyncManager : NSObject

    Swift

    class RLMSyncManager : NSObject
    Show on GitHub

  • A token object corresponding to a progress notification block on an RLMSyncSession. To stop notifications manually, call -stop on it. Notifications should be stopped before the token goes out of scope or is destroyed.

    Declaration

    Objective-C

    @interface RLMProgressNotificationToken : RLMNotificationToken

    Swift

    class RLMProgressNotificationToken : RLMNotificationToken
    Show on GitHub

  • An object encapsulating a Realm Object Server session. Sessions represent the communication between the client (and a local Realm file on disk), and the server (and a remote Realm at a given URL stored on a Realm Object Server).

    Sessions are always created by the SDK and vended out through various APIs. The lifespans of sessions associated with Realms are managed automatically.

    See more

    Declaration

    Objective-C

    @interface RLMSyncSession : NSObject

    Swift

    class RLMSyncSession : NSObject
    Show on GitHub

  • A RLMSyncUser instance represents a single Realm Object Server user account (or just user).

    A user may have one or more credentials associated with it. These credentials uniquely identify the user to a third-party auth provider, and are used to sign into a Realm Object Server user account.

    Note that users are only vended out via SDK APIs, and only one user instance ever exists for a given user account.

    See more

    Declaration

    Objective-C

    @interface RLMSyncUser : NSObject

    Swift

    class RLMSyncUser : NSObject
    Show on GitHub

  • An object intended to be passed between threads containing a thread-safe reference to its thread-confined object.

    To resolve a thread-safe reference on a target Realm on a different thread, pass to -[RLMRealm resolveThreadSafeReference:].

    Warning

    A RLMThreadSafeReference object must be resolved at most once. Failing to resolve a RLMThreadSafeReference will result in the source version of the Realm being pinned until the reference is deallocated.

    Note

    Prefer short-lived RLMThreadSafeReferences as the data for the version of the source Realm will be retained until all references have been resolved or deallocated.

    See

    RLMThreadConfined

    See

    -[RLMRealm resolveThreadSafeReference:]

    See more

    Declaration

    Objective-C

    @interface RLMThreadSafeReference < __covariant Confined
    : id <RLMThreadConfined>
> : NSObject @end

    Swift

    class RLMThreadSafeReference
    Show on GitHub

  • An RLMRealm instance (also referred to as a Realm) represents a Realm database.

    Realms can either be stored on disk (see +[RLMRealm realmWithURL:]) or in memory (see RLMRealmConfiguration).

    RLMRealm instances are cached internally, and constructing equivalent RLMRealm objects (for example, by using the same path or identifier) multiple times on a single thread within a single iteration of the run loop will normally return the same RLMRealm object.

    If you specifically want to ensure an RLMRealm instance is destroyed (for example, if you wish to open a Realm, check some property, and then possibly delete the Realm file and re-open it), place the code which uses the Realm within an @autoreleasepool {} and ensure you have no other strong references to it.

    Warning

    RLMRealm instances are not thread safe and cannot be shared across threads or dispatch queues. Trying to do so will cause an exception to be thrown. You must call this method on each thread you want to interact with the Realm on. For dispatch queues, this means that you must call it in each block which is dispatched, as a queue is not guaranteed to run all of its blocks on the same thread.
    See more

    Declaration

    Objective-C

    @interface RLMRealm : NSObject
    Show on GitHub

  • A token which is returned from methods which subscribe to changes to a Realm.

    Change subscriptions in Realm return an RLMNotificationToken instance, which can be used to unsubscribe from the changes. You must store a strong reference to the token for as long as you want to continue to receive notifications. When you wish to stop, call the -stop method. Notifications are also stopped if the token is deallocated.

    See more

    Declaration

    Objective-C

    @interface RLMNotificationToken : NSObject
    Show on GitHub