RavenDB

Schema free

Forget about tables, rows, mappings or complicated data-layers. RavenDB is a document-oriented database you can just dump all your objects into. Queries are amazingly fast and flexible.

Scalable

Sharding, replication and multi-tenancy are supported out-of-the-box. Scaling out is as easy as it gets.

Transactional

ACID transactions are fully supported, even between different nodes. If you put data in, it is going to stay there. We care about your data and we keep it safe.

High performance

RavenDB is a very fast persistence layer for every type of data model. Skip creating complicated mapping or multi-layer DALs, just persist your entities. It Just Works, and it does the Right Thing.

APIs

RavenDB comes with a carefully designed client API for .NET, Silverlight, Javascript and REST over HTTP.

Feature rich and extensible

Built with extensibility in mind, RavenDB can be easily extended via bundles. Many integration points ensure you can always squeeze more out of RavenDB. You aren't shackled to a One Size Fits None solution.

Carefully designed

Every bit of code was carefully considered. RavenDB was designed with best-practices in mind, and it ensures that everything Just Works.

Get the details from http://ravendb.net/