SingleSelectable<T> class
abstract
Selectable methods for returning or streaming single, non-nullable results.
Useful for refining the return type of a query, while still delegating whether to getSingle or watchSingle results to the consuming code.
// Retrieve a todo known to exist.
SingleSelectable<Todo> entryById(int id) {
return select(todos)..where((t) => t.id.equals(id));
}
final idGuaranteedToExist = 10;
entryById(idGuaranteedToExist).getSingle();
entryById(idGuaranteedToExist).watchSingle();
See also: MultiSelectable for exposing multi-value methods and SingleOrNullSelectable for exposing nullable value methods.
Constructors
Properties
- hashCode → int
-
The hash code for this object.
no setterinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
getSingle(
) → Future< T> - Executes this statement, like Selectable.get, but only returns one value. the query returns no or too many rows, the returned future will complete with an error.
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
-
watchSingle(
) → Stream< T> -
Creates an auto-updating stream of this statement, similar to
Selectable.watch. However, it is assumed that the query will only emit
one result, so instead of returning a
Stream<List<T>>, this returns aStream<T>. If, at any point, the query emits no or more than one rows, an error will be added to the stream instead.
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited