upscaledb - A very fast lightweight embedded database engine with a built-in query language.

upscaledb is a fast key-value database which optimizes storage and algorithms for your specific data types. upscaledb can be used to build all functions of a typical SQL database, tailored to the specific needs of your application, and directly linked into your program.

Its blazingly fast analytical functions and database cursors make it a natural fit to process data whenever a SQL database is not fast enough. A simple and self-documenting API; extensive documentation and a tutorial are provided. APIs for C/C++, Java, Python, .NET (i.e. C#, VB.NET), Erlang/Elixir and PHP are available.