LiteDB - A .NET NoSQL Document Store in a single data file

First v5-alpha version was released

LiteDB is a small, fast and lightweight NoSQL embedded database.

Serverless NoSQL Document Store
Simple API, similar to MongoDB
100% C# code for .NET 4.5 / NETStandard 2.0 in a single DLL (less than 300kb)
Thread-safe
ACID with full transaction support
Data recovery after write failure (WAL log file)
Datafile encryption using DES (AES) cryptography
Map your POCO classes to BsonDocument using attributes or fluent mapper API
Store files and stream data (like GridFS in MongoDB)
Single data file storage (like SQLite)
Index document fields for fast search (up to 32 indexes per collection)
LINQ support for queries
SQL-Like commands to access/transform data
LiteDB Studio - Nice UI for data access
Pretty fast - compare results with SQLite here
Open source and free for everyone - including commercial use
Install from NuGet: Install-Package LiteDB

New v5

Take a look at the all new version v5 here

Documentation

Visit the Wiki for full documentation. For simplified chinese version, check here.

Download

Download the source code or binary only in LiteDB Releases

LiteDB Community

Help LiteDB grow its user community by answering this simple survey

How to use LiteDB

A quick example for storing and searching documents:

// Create your POCO class
public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
    public string[] Phones { get; set; }
    public bool IsActive { get; set; }
}

// Open database (or create if doesn't exist)
using(var db = new LiteDatabase(@"MyData.db"))
{
    // Get customer collection
    var col = db.GetCollection<Customer>("customers");

    // Create your new customer instance
    var customer = new Customer
    { 
        Name = "John Doe", 
        Phones = new string[] { "8000-0000", "9000-0000" }, 
        Age = 39,
        IsActive = true
    };

    // Create unique index in Name field
    col.EnsureIndex(x => x.Name, true);

    // Insert new customer document (Id will be auto-incremented)
    col.Insert(customer);

    // Update a document inside a collection
    customer.Name = "Joana Doe";

    col.Update(customer);

    // Use LINQ to query documents (with no index)
    var results = col.Find(x => x.Age > 20);
}

Using fluent mapper and cross document reference for more complex data models

// DbRef to cross references
public class Order
{
    public ObjectId Id { get; set; }
    public DateTime OrderDate { get; set; }
    public Address ShippingAddress { get; set; }
    public Customer Customer { get; set; }
    public List<Product> Products { get; set; }
}        

// Re-use mapper from global instance
var mapper = BsonMapper.Global;

// "Products" and "Customer" are from other collections (not embedded document)
mapper.Entity<Order>()
    .DbRef(x => x.Customer, "customers")   // 1 to 1/0 reference
    .DbRef(x => x.Products, "products")    // 1 to Many reference
    .Field(x => x.ShippingAddress, "addr"); // Embedded sub document
            
using(var db = new LiteDatabase("MyOrderDatafile.db"))
{
    var orders = db.GetCollection<Order>("orders");
        
    // When query Order, includes references
    var query = orders
        .Include(x => x.Customer)
        .Include(x => x.Products) // 1 to many reference
        .Find(x => x.OrderDate <= DateTime.Now);

    // Each instance of Order will load Customer/Products references
    foreach(var order in query)
    {
        var name = order.Customer.Name;
        ...
    }
}

Where to use?

Desktop/local small applications
Application file format
Small web applications
One database per account/user data store
Few concurrent write operations

Plugins

A GUI viewer tool: https://github.com/falahati/LiteDBViewer
A GUI editor tool: https://github.com/JosefNemec/LiteDbExplorer
Lucene.NET directory: https://github.com/sheryever/LiteDBDirectory
LINQPad support: https://github.com/adospace/litedbpad
F# Support: https://github.com/Zaid-Ajaj/LiteDB.FSharp

Changelog

Change details for each release are documented in the release notes.

Code Signing

LiteDB is digitally signed courtesy of SignPath

License

MIT

LiteDB v5

After more than a year of hard working, v5 is comming!

What's new in v5?

New Storage Engine
- New WAL (Write-Ahead Logging) for fast durability
- Database lock per collection
- MultiVersion Concurrency Control (Snapshots & Checkpoint)
- Multi concurrent Stream readers - Single async writer
- No lock for reader
- Up to 32 indexes per collection
- Atomic multi-document transactions
- PageSize: 8KB
New BsonExpression
- New super-fast tokenizer parser
- Clean syntax with optional use of $
- Input/Output parameter support: @name
- Simplified document notation { _id, name, year }
- Support partial BSON document: read/deserialize only used data in query
- New Map function $.Items => UPPER(@.Name)
System Collections
- Support query over internal collection
- $transactions, $database, $dump
New QueryBuilder
- Fluent API for write queries
- Simple syntax using BsonExpressions
- Support OrderBy/GroupBy expressions
- Query optimization with Explain Plan
- Aggregate functions
- LINQ to BsonExpression query support - easy to use (and similar to EF)
New SQL-Like syntax
- Simple SQL syntax for any command
- Syntax near to SQL ANSI
- Support INSERT/UPDATE/DELETE/...
- MapReduce using GroupBy/Having
New Native UI - LiteDB.Studio
- WinForms app to manipulate the database
- Based on SQL commands
- Show results in grid or as text
- Multi tabs, multi threads, multi transactions

What was dropped?

Single process only - optimized for multi thread (open file as exclusive mode)
Dropped .NET 3.5/4.0 - works only in .NET 4.5+ and .NETStandard 1.3/2.0
Shell commands (use SQL commands)

.. but still...

Embedded support
Single database file
Single DLL, no dependencies and 100% C#
100% free open source

klettier / LiteDB