HiveList and lazy box

Handle large data with LazyBox and HiveList.

What is a LazyBox?

A LazyBox loads values from disk only when they are requested. A regular box loads all values into memory on open; a LazyBox reads them when you call await box.get('key'). This saves memory for large datasets.

final box = await Hive.openLazyBox('large');
final value = await box.get('item1');

HiveList

HiveList is a special list type that holds references to objects in other boxes. Instead of copying an object into multiple boxes, you reference it with HiveList. This prevents data duplication and creates relationships between boxes.

// HiveList holds references to objects in boxes
// Creates relationships without duplicating data

Exercise Use a LazyBox

Open a lazy box named 'large'. Put 'değer' under key 'item1'. Read the value with await and print it. Close the box.

Show example solution

import 'package:hive/hive.dart';

void main() async {
  Hive.init('hive_data');
  final box = await Hive.openLazyBox('large');
  await box.put('item1', 'değer');
  final value = await box.get('item1');
  print(value);
  await box.close();
}

Test yourself

What is the main difference between LazyBox and Box?
- LazyBox holds only strings, Box holds any type
- Box works only in memory, LazyBox on disk
- They are completely identical
- LazyBox loads values on demand, Box loads all into memory
Show answer

LazyBox loads values on demand, Box loads all into memory — Box loads all values into memory on open; LazyBox reads from disk when get is called.

Open a lazy box

final box = await Hive.____('large_data');

Show answer

final box = await Hive.openLazyBox('large_data');

LazyBox and HiveList parts

LazyBox

Loads on demand
openLazyBox

Opens a lazy box
HiveList

Cross-box reference
await box.get

Async value read

Next lesson: Summary - Hive

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