ToMany<EntityT> class

A to-many relation of an entity that references multiple objects of a "target" entity EntityT.

Example:

@Entity()
class Student {
  final teachers = ToMany<Teacher>();
}

Implements the List interface and uses lazy initialization. The target objects are only read from the database when the list is first accessed.

Tracks when target objects are added and removed. Common usage:

  • add target objects to the relation.
  • remove target objects from the relation.
  • removeAt target objects at a specific index.

To apply (persist) the changes to the database, call applyToDb or put the object with the ToMany. For important details, see the notes about relations of Box.put.

// Example 1: add target objects to a relation
student.teachers.add(teacher1);
student.teachers.add(teacher2);
store.box<Student>().put(student);

// Example 2: remove a target object from the relation
student.teachers.removeAt(index);
student.teachers.applyToDb();
// or store.box<Student>().put(student);

In the database, the target objects are referenced by their IDs, which are persisted as part of the relation of the object with the ToMany.

To get all objects with a ToMany that reference a target object, see Backlink.

Mixed-in types
Available extensions

Constructors

ToMany({List<EntityT>? items})
Create a ToMany relationship.

Properties

first ↔ EntityT
The first element.
getter/setter pairinherited
hashCode → int
The hash code for this object.
no setterinherited
isEmpty → bool
Whether this collection has no elements.
no setterinherited
isNotEmpty → bool
Whether this collection has at least one element.
no setterinherited
iterator → Iterator<EntityT>
A new Iterator that allows iterating the elements of this Iterable.
no setterinherited
last ↔ EntityT
The last element.
getter/setter pairinherited
length ↔ int
The number of objects in this list.
getter/setter pairoverride
reversed → Iterable<EntityT>
An Iterable of the objects in this list in reverse order.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
single → EntityT
Checks that this iterable has only one element, and returns that element.
no setterinherited

Methods

add(EntityT element) → void
Prepares to add the given target object to this relation.
override
addAll(Iterable<EntityT> iterable) → void
Like add, but for multiple target objects.
override
any(bool test(EntityT element)) → bool
Checks whether any element of this iterable satisfies test.
inherited
applyToDb({Store? existingStore, PutMode mode = PutMode.put, Transaction? tx}) → void
Saves changes (added and removed entities) made to this relation to the database. For some important details, see the notes about relations of Box.put.
asMap() → Map<int, EntityT>
An unmodifiable Map view of this list.
inherited
cast<R>() → List<R>
Returns a view of this list as a list of R instances.
inherited
clear() → void
Removes all objects from this list; the length of the list becomes zero.
inherited
contains(Object? element) → bool
Whether the collection contains an element equal to element.
inherited
elementAt(int index) → EntityT
Returns the indexth element.
inherited
every(bool test(EntityT element)) → bool
Checks whether every element of this iterable satisfies test.
inherited
expand<T>(Iterable<T> f(EntityT element)) → Iterable<T>
Expands each element of this Iterable into zero or more elements.
inherited
fillRange(int start, int end, [EntityT? fill]) → void
Overwrites a range of elements with fillValue.
inherited
firstWhere(bool test(EntityT element), {EntityT orElse()?}) → EntityT
The first element that satisfies the given predicate test.
inherited
fold<T>(T initialValue, T combine(T previousValue, EntityT element)) → T
Reduces a collection to a single value by iteratively combining each element of the collection with an existing value
inherited
followedBy(Iterable<EntityT> other) → Iterable<EntityT>
Creates the lazy concatenation of this iterable and other.
inherited
forEach(void action(EntityT element)) → void
Invokes action on each element of this iterable in iteration order.
inherited
getRange(int start, int end) → Iterable<EntityT>
Creates an Iterable that iterates over a range of elements.
inherited
indexOf(Object? element, [int start = 0]) → int
The first index of element in this list.
inherited
indexWhere(bool test(EntityT element), [int start = 0]) → int
The first index in the list that satisfies the provided test.
inherited
insert(int index, EntityT element) → void
Inserts element at position index in this list.
inherited
insertAll(int index, Iterable<EntityT> iterable) → void
Inserts all objects of iterable at position index in this list.
inherited
join([String separator = ""]) → String
Converts each element to a String and concatenates the strings.
inherited
lastIndexOf(Object? element, [int? start]) → int
The last index of element in this list.
inherited
lastIndexWhere(bool test(EntityT element), [int? start]) → int
The last index in the list that satisfies the provided test.
inherited
lastWhere(bool test(EntityT element), {EntityT orElse()?}) → EntityT
The last element that satisfies the given predicate test.
inherited
map<T>(T f(EntityT element)) → Iterable<T>
The current elements of this iterable modified by toElement.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
reduce(EntityT combine(EntityT previousValue, EntityT element)) → EntityT
Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.
inherited
remove(Object? element) → bool
Prepares to remove the target object from this relation.
override
removeAt(int index) → EntityT
Removes the object at position index from this list.
inherited
removeLast() → EntityT
Removes and returns the last object in this list.
inherited
removeRange(int start, int end) → void
Removes a range of elements from the list.
inherited
removeWhere(bool test(EntityT element)) → void
Removes all objects from this list that satisfy test.
inherited
replaceRange(int start, int end, Iterable<EntityT> newContents) → void
Replaces a range of elements with the elements of replacements.
inherited
retainWhere(bool test(EntityT element)) → void
Removes all objects from this list that fail to satisfy test.
inherited
setAll(int index, Iterable<EntityT> iterable) → void
Overwrites elements with the objects of iterable.
inherited
setRange(int start, int end, Iterable<EntityT> iterable, [int skipCount = 0]) → void
Writes some elements of iterable into a range of this list.
inherited
shuffle([Random? random]) → void
Shuffles the elements of this list randomly.
inherited
singleWhere(bool test(EntityT element), {EntityT orElse()?}) → EntityT
The single element that satisfies test.
inherited
skip(int count) → Iterable<EntityT>
Creates an Iterable that provides all but the first count elements.
inherited
skipWhile(bool test(EntityT element)) → Iterable<EntityT>
Creates an Iterable that skips leading elements while test is satisfied.
inherited
sort([int compare(EntityT a, EntityT b)?]) → void
Sorts this list according to the order specified by the compare function.
inherited
sublist(int start, [int? end]) → List<EntityT>
Returns a new list containing the elements between start and end.
inherited
take(int count) → Iterable<EntityT>
Creates a lazy iterable of the count first elements of this iterable.
inherited
takeWhile(bool test(EntityT element)) → Iterable<EntityT>
Creates a lazy iterable of the leading elements satisfying test.
inherited
toList({bool growable = true}) → List<EntityT>
Creates a List containing the elements of this Iterable.
override
toSet() → Set<EntityT>
Creates a Set containing the same elements as this iterable.
inherited
toString() → String
A string representation of this object.
inherited
where(bool test(EntityT element)) → Iterable<EntityT>
Creates a new lazy Iterable with all elements that satisfy the predicate test.
inherited
whereType<T>() → Iterable<T>
Creates a new lazy Iterable with all elements that have type T.
inherited

Operators

operator +(List<EntityT> other) → List<EntityT>
Returns the concatenation of this list and other.
inherited
operator ==(Object other) → bool
The equality operator.
inherited
operator [](int index) → EntityT
Gets the target object at the given index.
override
operator []=(int index, EntityT element) → void
Sets the value at the given index in the list to value.
override