Nitrite Database

NOsql Object (NO₂ a.k.a. Nitrite) database is an open source nosql embedded document store. It supports both in-memory and file based persistent store.

Nitrite is an embedded database ideal for desktop, mobile or small web applications.

It features:

• Embedded, serverless
• Simple API
• Document-oriented
• Schemaless document collection and object repository
• Indexing and full-text search
• Simple query api
• In-memory store
• Transaction support
• Schema migration support
• Encryption support

Getting Started with Nitrite

How To Install

To use Nitrite in any Flutter application, add the below packages in your project:

dart pub add nitrite

Quick Examples

Initialize Database

// initialization Nitrite database with in-memory store
var db = await Nitrite.builder()
    .openOrCreate(username: 'user', password: 'pass123');

Create a Collection/ObjectRepository

// Create a Nitrite Collection
var collection = await db.getCollection("test");

// Create an Object Repository
var repository = await db.getRepository<Book>();

Code generators for Entity classes

The nitrite generator package can automatically generate entity classes from dart classes. It uses source_gen package to generate code. To use the generator, add the below packages:

dart pub add nitrite_generator --dev
dart pub add build_runner --dev

And use below annotations in your dart classes:

import 'package:nitrite/nitrite.dart';

part 'book.no2.dart';

@Convertable(className: 'MyBookConverter')
@Entity(name: 'books', indices: [
  Index(fields: ['tags'], type: IndexType.nonUnique),
  Index(fields: ['description'], type: IndexType.fullText),
  Index(fields: ['price', 'publisher']),
])
class Book with _$BookEntityMixin {
  // id field
  @Id(fieldName: 'book_id', embeddedFields: ['isbn', 'book_name'])
  @DocumentKey(alias: 'book_id')
  BookId? bookId;

  String? publisher;
  double? price;
  List<String> tags = [];
  String? description;

  Book([
    this.bookId,
    this.publisher,
    this.price,
    this.tags = const [],
    this.description,
  ]);
  
}

// composite id class
@Convertable()
class BookId {
  String? isbn;

  // set a different field name in the document
  @DocumentKey(alias: "book_name")
  String? name;

  // ignore the field in the document
  @IgnoredKey()
  String? author;
}

CRUD Operations

// create a document to populate data
var doc = createDocument("firstName", "fn1")
    .put("lastName", "ln1")
    .put("birthDay", DateTime.parse("2012-07-01T16:02:48.440Z"))
    .put("data", [1, 2, 3])
    .put("list", ["one", "two", "three"])
    .put("body", "a quick brown fox jump over the lazy dog")
    .put("books", [
      createDocument("name", "Book ABCD").put("tag", ["tag1", "tag2"]),
      createDocument("name", "Book EFGH").put("tag", ["tag3", "tag1"]),
      createDocument("name", "No Tag")
    ]);

// insert the document
await collection.insert(doc);

// find documents from the collection
var cursor = collection.find(filter: and([
      where('lastName').eq('ln1'),
      where("firstName").notEq("fn1"),
      where("list").eq("four"),
    ]),
);

// update the document
await collection.update(
  where('firstName').eq('fn1'),
  createDocument('firstName', 'fn1-updated'),
  updateOptions(insertIfAbsent: true),
);

// remove the document
await coll.remove(where('firstName').eq('fn1-updated'));

// insert an object in repository
var bookId = BookId();
bookId.isbn = 'abc123';
bookId.author = 'xyz';
bookId.name = 'Book 1';

var book = Book();
book.bookId = bookId;
book.tags = ['tag1', 'tag2'];
book.description = 'A book about nitrite database';
book.publisher = 'rando publisher';
book.price = 150.5;

await repository.insert(book);

Create Indices

// create document index
await collection.createIndex(['firstName', 'lastName']); // unique index
await collection.createIndex(['firstName'], indexOptions(IndexType.nonUnique))

// create object index. It can also be provided via annotation
await repository.createIndex("publisher", indexOptions(IndexType.NonUnique));

Query a Collection

var cursor = collection.find(
  filter: and([
    where('lastName').eq('ln2'),
    where("firstName").notEq("fn1"),
    where("list").eq("four")
  ]),
);

await for (var d in cursor) {
  print(d);
}

// get document by a nitrite id
var document = await collection.getById(nitriteId);

// query an object repository and create the first result
var cursor = repository.find(
    filter: where('book_id.isbn').eq('abc123'),
);
var book = await cursor.first();

Transaction

Nitrite has support for transaction. Transaction is supported only for file based storage.

var session = db.createSession();
var tx = await session.beginTransaction();

var txRepo = await tx.getRepository<Book>();
await txRepo.insert(book);
await tx.commit();

or, another way to do the same thing:

var session = db.createSession();
await session.executeTransaction((tx) async {
  var txRepo = await tx.getRepository<Book>();
  await txRepo.insertMany([book1, book2, book3]);
});

Schema Migration

Nitrite supports schema migration. It can be used to migrate data from one schema version to another. It is useful when you want to change the schema of your application without losing the existing data.

var migration = Migration(
  3,
  4,
  (instructionSet) {
    instructionSet
        .forCollection('test')
        .addField('age', defaultValue: 10);
  },
);

db = await Nitrite.builder()
      .loadModule(storeModule)
      .schemaVersion(4)
      .addMigrations([migration])
      .openOrCreate();

More details are available in the reference document.