Realm

Realm React Native brings the modern design & simplicity you expect from Realm, and will allow you to target both iOS and Android with the same codebase.
Realm is not an ORM, and is not built on top of SQLite. Instead we’ve built a full database for mobile app developers, one that uses native JavaScript objects that are dynamically mapped to a full, custom database engine (not just a key-value store). This allows us to provide a simple API while preserving performance. With Realm, you can model complex data, link objects in a graph, and compose advanced queries.

 Example:

class Test {}
Test.schema = {
    name: 'Ron',
    properties: {
        name: 'string',
        age: 'int',
    }
};

let realm = new Realm({schema: [Test]});

realm.write(() => {
    realm.create('Test', { name: 'Ram', age: 3 });
});
Realm’s ease of use doesn’t come at a performance cost. Because of its memory mapping, lazy loading, and custom storage engine, Realm is usually faster than SQLite or AsyncStorage despite offering a rich object-based API. 

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