SimpleDB/dev is a local instance of Amazon's SimpleDB. It runs as a server on your local machine and replicates the SimpleDB REST API as specified in Amazon's technical documentation. It implements every SimpleDB query-action and includes a large suite of tests, created from the query examples provided by Amazon.
DeveelDB is an embedded SQL database management system for .NET, implementing all the features of the SQL92 specifications (transactions, triggers, procedures, functions, etc.). The aim is to provide .NET and Mono developers with a fully functional, powerful, and embeddable database system that can be used in several contexts, managing small to large amounts of data.
jpt is a generic database toolkit. The package's main component is the libjpt library, which can be easily linked into C++ and C programs. A jpt database consists of a single sparse table, with an arbitrary number of rows and columns. The programming interface is simple, and the data structures are designed for fast random inserts and lookups.
MckoiDDB is a distributed database system for applications that need to support low latency random access (read and write) queries on datasets that span a cluster of machines in a network. The software provides the system for managing the storage of data over the network cluster and a client API for accessing and querying the data. The MckoiDDB system can scale up or down as resources are added or removed in the network, and is flexible in how the logical data models of an application are designed and implemented. MckoiDDB can be installed on high-speed private networks and over instances in Cloud service providers.
Neo4j is a graph database, a fully transactional database that stores data structured as graphs. A graph is a flexible data structure that allows for a more agile and rapid style of development. You can think of Neo4j as a high-performance graph engine with all the features of a mature and robust database. The programmer works with an object-oriented, flexible network structure rather than with strict and static tables, yet enjoys all the benefits of a fully transactional, enterprise-strength database. The community edition is GPLv3 licensed, while the advanced and enterprise editions are AGPLv3 licensed.
The OODBMS/DBMS ODABA is an terminology-oriented database management system (TODBMS) on a high conceptual level. This is an extension of the ODBMS concept according to ODMG 3. It provides a number of enhanced features based on natural language analysis. Beside the database kernel, a number of tools are provided for database design, documentation, and fast development. ODABA provides a powerful interface (C++, .NET) and an ODABA Script Interface (OSI), a C++/JAVA like scripting language, which provides easy access to the database.
PostGIS adds support for geographic objects to the PostgreSQL object-relational database. In effect, PostGIS "spatially enables" the PostgreSQL server, allowing it to be used as a backend spatial database for geographic information systems (GIS), much like ESRI's SDE or Oracle's Spatial extension.