Modern projects need to manipulate with huge data amount, as result the necessity of high scalability and high performance is very actual and always grows.
RDBMS databases cannot supply ultimate solution and alternative concepts like in NoSQL systems look very interesting.
The first interesting option is key-value stores like Google Big Table or Cassandra that provide fast and extremely large-scale solution but you can forget the comfort work with SQL queries like in RDBMS databases.
Another option that tries to combine between advantages of RDBMS databases and key-values stores is document-oriented databases like MonogDB.
MongoDB is development by commercial company as open-source project written in C++.
There are a lot of documentation, tutorials and samples on project site.
