DatabaseReference class

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

This class is the starting point for all Firebase Database operations. After you’ve obtained your first DatabaseReference via FirebaseDatabase.reference(), you can use it to read data (ie. onChildAdded), write data (ie. setValue), and to create new DatabaseReferences (ie. child).

Inheritance
  • Object
  • Query
  • DatabaseReference

Properties

key → String
Gets the last token in a Firebase Database location (e.g. ‘fred’ in https://SampleChat.firebaseIO-demo.com/users/fred)
read-only
hashCode → int
The hash code for this object.
read-only, inherited
onChildAdded → Stream<Event>
Fires when children are added.
read-only, inherited
onChildChanged → Stream<Event>
Fires when children are changed.
read-only, inherited
onChildMoved → Stream<Event>
Fires when children are moved.
read-only, inherited
onChildRemoved → Stream<Event>
Fires when children are removed. previousChildKey is null.
read-only, inherited
onValue → Stream<Event>
Fires when the data at this location is updated. previousChildKey is null.
read-only, inherited
path → String
Slash-delimited path representing the database location of this query.
read-only, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited

Methods

child(String path) DatabaseReference
Gets a DatabaseReference for the location at the specified relative path. The relative path can either be a simple child key (e.g. ‘fred’) or a deeper slash-separated path (e.g. ‘fred/name/first’).
onDisconnect() OnDisconnect
parent() DatabaseReference
Gets a DatabaseReference for the parent location. If this instance refers to the root of your Firebase Database, it has no parent, and therefore parent() will return null.
push() DatabaseReference
Generates a new child location using a unique key and returns a DatabaseReference to it. This is useful when the children of a Firebase Database location represent a list of items. [...]
remove() → Future<void>
Remove the data at this Firebase Database location. Any data at child locations will also be deleted. [...]
root() DatabaseReference
Gets a FIRDatabaseReference for the root location.
runTransaction(TransactionHandler transactionHandler, { Duration timeout: const Duration(seconds: 5) }) → Future<TransactionResult>
Performs an optimistic-concurrency transactional update to the data at this Firebase Database location.
set(dynamic value, { dynamic priority }) → Future<void>
Write value to the location with the specified priority if applicable. [...]
setPriority(dynamic priority) → Future<void>
Sets a priority for the data at this Firebase Database location. [...]
update(Map<String, dynamic> value) → Future<void>
Update the node with the value
buildArguments() → Map<String, dynamic>
inherited
endAt(dynamic value, { String key }) Query
Create a query constrained to only return child nodes with a value less than or equal to the given value, using the given orderBy directive or priority as default, and optionally only child nodes with a key less than or equal to the given key.
inherited
equalTo(dynamic value, { String key }) Query
Create a query constrained to only return child nodes with the given value (and key, if provided). [...]
inherited
keepSynced(bool value) → Future<void>
By calling keepSynced(true) on a location, the data for that location will automatically be downloaded and kept in sync, even when no listeners are attached for that location. Additionally, while a location is kept synced, it will not be evicted from the persistent disk cache.
inherited
limitToFirst(int limit) Query
Create a query with limit and anchor it to the start of the window.
inherited
limitToLast(int limit) Query
Create a query with limit and anchor it to the end of the window.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
once() → Future<DataSnapshot>
Listens for a single value event and then stops listening.
inherited
orderByChild(String key) Query
Generate a view of the data sorted by values of a particular child key. [...]
inherited
orderByKey() Query
Generate a view of the data sorted by key. [...]
inherited
orderByPriority() Query
Generate a view of the data sorted by priority. [...]
inherited
orderByValue() Query
Generate a view of the data sorted by value. [...]
inherited
reference() DatabaseReference
Obtains a DatabaseReference corresponding to this query's location.
inherited
startAt(dynamic value, { String key }) Query
Create a query constrained to only return child nodes with a value greater than or equal to the given value, using the given orderBy directive or priority as default, and optionally only child nodes with a key greater than or equal to the given key.
inherited
toString() → String
Returns a string representation of this object.
inherited

Operators

operator ==(dynamic other) → bool
The equality operator.
inherited