FirebaseDatabase Framework Reference

Classes

The following classes are available globally.

• DataSnapshot

  A DataSnapshot contains data from a Firebase Database location. Any time you read Firebase data, you receive the data as a DataSnapshot.

  DataSnapshots are passed to the blocks you attach with observe(_:with:) or observeSingleEvent(of:with:). They are efficiently-generated immutable copies of the data at a Firebase Database location. They can’t be modified and will never change. To modify data at a location, use a DatabaseReference (e.g. with setValue(_:)).

  Declaration

  Swift

  class DataSnapshot : NSObject, @unchecked Sendable

• DatabaseReference

  A FIRDatabaseReference represents a particular location in your Firebase Database and can be used for reading or writing data to that Firebase Database location.

  This class is the starting point for all Firebase Database operations. After you’ve obtained your first FIRDatabaseReference via [FIRDatabase reference], you can use it to read data (ie. observeEventType:withBlock:), write data (ie. setValue:), and to create new FIRDatabaseReferences (ie. child:).

  Declaration

  Swift

  class DatabaseReference : DatabaseQuery

• Database

  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().

  Declaration

  Swift

  class Database : NSObject

• DatabaseQuery

  A DatabaseQuery instance represents a query over the data at a particular location.

  You create one by calling one of the query methods (queryOrdered(byChild:), queryStarting(atValue:), etc.) on a DatabaseReference. The query methods can be chained to further specify the data you are interested in observing.

  Declaration

  Swift

  class DatabaseQuery : NSObject

• MutableData

  A MutableData instance is populated with data from a Firebase Database location. When you are using runTransactionBlock(_:), you will be given an instance containing the current data at that location. Your block will be responsible for updating that instance to the data you wish to save at that location, and then returning using TransactionResult.success(withValue:).

  To modify the data, set its value property to any of the Objective-C types supported by Firebase Database, or any equivalent natively bridgeable Swift type:

  • NSNumber (includes booleans)
  • NSDictionary
  • NSArray
  • NSString
  • nil / NSNull to remove the data

  Note that changes made to a child MutableData instance will be visible to the parent.

  Declaration

  Swift

  class MutableData : NSObject

• ServerValue

  Placeholder values you may write into Firebase Database as a value or priority that will automatically be populated by the Firebase Database server.

  Declaration

  Swift

  class ServerValue : NSObject

• TransactionResult

  Used for runTransactionBlock(_:). A TransactionResult instance is a container for the results of the transaction.

  Declaration

  Swift

  class TransactionResult : NSObject