devsite/tools/jazzy/templates

FirebaseDatabase Framework Reference

FIRDatabase


@interface FIRDatabase : NSObject

The entry point for accessing a Firebase Database. You can get an instance by calling Database.database(). To access a location in the database and read or write data, use FIRDatabase.reference().

  • Unavailable

    use the database method instead

    The NSObject initializer that has been marked as unavailable. Use the database class method instead.

    Declaration

    Objective-C

    - (nonnull instancetype)init;

  • Gets the instance of Database for the default FirebaseApp.

    Declaration

    Objective-C

    + (nonnull FIRDatabase *)database;

    Return Value

    A Database instance.

  • Gets a Database instance for the specified URL.

    Declaration

    Objective-C

    + (nonnull FIRDatabase *)databaseWithURL:(nonnull NSString *)url;

    Parameters

    url

    The URL to the Firebase Database instance you want to access.

    Return Value

    A Database instance.

  • Gets a Database instance for the specified URL, using the specified FirebaseApp.

    Declaration

    Objective-C

    + (nonnull FIRDatabase *)databaseForApp:(nonnull FIRApp *)app
                                    URL:(nonnull NSString *)url;

    Parameters

    app

    The app to get a Database for.
    url

    The URL to the Firebase Database instance you want to access.

    Return Value

    A Database instance.

  • Gets an instance of Database for a specific FirebaseApp.

    Declaration

    Objective-C

    + (nonnull FIRDatabase *)databaseForApp:(nonnull FIRApp *)app;

    Parameters

    app

    The app to get a Database for.

    Return Value

    A Database instance.

  • app

    The app instance to which this Database belongs.

    Declaration

    Objective-C

    @property (nonatomic, weak, readonly) FIRApp *_Nullable app;

  • Gets a DatabaseReference for the root of your Firebase Database.

    Declaration

    Objective-C

    - (nonnull FIRDatabaseReference *)reference;

  • Gets a DatabaseReference for the provided path.

    Declaration

    Objective-C

    - (nonnull FIRDatabaseReference *)referenceWithPath:(nonnull NSString *)path;

    Parameters

    path

    Path to a location in your Firebase Database.

    Return Value

    A DatabaseReference pointing to the specified path.

  • Gets a DatabaseReference for the provided URL. The URL must be a URL to a path within this Firebase Database. To create a DatabaseReference to a different database, create a FirebaseApp with an Options object configured with the appropriate database URL.

    Declaration

    Objective-C

    - (nonnull FIRDatabaseReference *)referenceFromURL:
    (nonnull NSString *)databaseUrl;

    Parameters

    databaseUrl

    A URL to a path within your database.

    Return Value

    A DatabaseReference for the provided URL.

  • The Firebase Database client automatically queues writes and sends them to the server at the earliest opportunity, depending on network connectivity. In some cases (e.g. offline usage) there may be a large number of writes waiting to be sent. Calling this method will purge all outstanding writes so they are abandoned.

    All writes will be purged, including transactions and onDisconnect writes. The writes will be rolled back locally, perhaps triggering events for affected event listeners, and the client will not (re-)send them to the Firebase Database backend.

    Declaration

    Objective-C

    - (void)purgeOutstandingWrites;

  • Shuts down the connection to the Firebase Database backend until goOnline() is called.

    Declaration

    Objective-C

    - (void)goOffline;

  • Resumes the connection to the Firebase Database backend after a previous goOffline() call.

    Declaration

    Objective-C

    - (void)goOnline;

  • The Firebase Database client will cache synchronized data and keep track of all writes you’ve initiated while your application is running. It seamlessly handles intermittent network connections and re-sends write operations when the network connection is restored.

    However by default your write operations and cached data are only stored in-memory and will be lost when your app restarts. By setting this value to true, the data will be persisted to on-device (disk) storage and will thus be available again when the app is restarted (even when there is no network connectivity at that time). Note that this property must be set before creating your first DatabaseReference and only needs to be called once per application.

    Declaration

    Objective-C

    @property (nonatomic) BOOL persistenceEnabled;

  • By default the Firebase Database client will use up to 10MB of disk space to cache data. If the cache grows beyond this size, the client will start removing data that hasn’t been recently used. If you find that your application caches too little or too much data, call this method to change the cache size. This property must be set before creating your first DatabaseReference and only needs to be called once per application.

    Note that the specified cache size is only an approximation and the size on disk may temporarily exceed it at times. Cache sizes smaller than 1 MB or greater than 100 MB are not supported.

    Declaration

    Objective-C

    @property (nonatomic) NSUInteger persistenceCacheSizeBytes;

  • Sets the dispatch queue on which all events are raised. The default queue is the main queue.

    Note that this must be set before creating your first Database reference.

    Declaration

    Objective-C

    @property (nonatomic, strong) dispatch_queue_t _Nonnull callbackQueue;

  • Enables verbose diagnostic logging.

    Declaration

    Objective-C

    + (void)setLoggingEnabled:(BOOL)enabled;

    Parameters

    enabled

    true to enable logging, false to disable.

  • Retrieve the Firebase Database SDK version.

    Declaration

    Objective-C

    + (nonnull NSString *)sdkVersion;

  • Configures the database to use an emulated backend instead of the default remote backend.

    Declaration

    Objective-C

    - (void)useEmulatorWithHost:(nonnull NSString *)host port:(NSInteger)port;