PumpkinDB - Event Sourcing Database Engine
PumpkinDB is a event sourcing database engine that doesn't overwrite data. It features include Immutable key/value storage, ACID transactions, Binary keys and values (allows any encoding to be used: JSON, XML, Protobuf, Cap'n Proto, etc.), An embedded programming language (PumpkinScript), A range of event indexing and querying primitives.
The core ideas behind PumpkinDB stem from the so called lazy event sourcing approach which is based on storing and indexing events while delaying domain binding for as long as possible. That said, the intention of this database is to be a building block for different kinds of event sourcing systems, ranging from the classic one (using it as an event store) all the way to the lazy one (using indices) and anywhere in between. It's also possible to implement different approaches within a single database for different parts of the domain.