MariaDB is a database server that offers drop-in replacement functionality for MySQL. It is built by some of the original authors of MySQL, with assistance from the broader community. In addition to the core functionality of MySQL, it offers a rich set of feature enhancements including alternate storage engines, server optimizations, and patches.
HailDB is a relational database in shared library form that can be embedded into applications. It is not a SQL database, although you can use this library as the storage backend for a SQL database. It features a clean and simple API and is a continuation of the Embedded InnoDB project. With the addition of the HailDB plugin to Drizzle, you get a full SQL interface.
BlackRay is a relational database system designed to offer performance features commonly associated with search engines. It offers SQL support and sophisticated operational and management features. Load-balancing and operational stability by means of N+1 redundance are included. BlackRay is called a "Data Engine" since it combines traditional, relational database features and SQL with the power and flexibility of search engines. It is a true hybrid, offering transaction support, data-versioned snapshots, and sophisticated function-based indices. Wildcards, phonetic, and fuzzy logic searches are supported, as well. BlackRay supports a subset of the SQL92 standard and provides JDBC/ODBC/native driver options via the PostgreSQL protocol, in addition to an API based query option. The project is released under the GPLv2, with some drivers available under BSD-style licenses. Commercial support contracts are available as well.
PBL (The Program Base Library) is a C library of array/linked list, hash/tree set, and key file functions that can be used in a C or C++ project. It is highly portable and compiles warning-free on Linux gcc, Windows Cygwin gcc, Mac OS X, and Windows Microsoft Visual C++ 2008 Express Edition.
BaseX is a light-weight, high-performance, and scalable XML database system and XPath/XQuery processor, including full support for the W3C Update and Full Text extensions. An interactive and user-friendly GUI frontend gives you great insight into large XML data instances. It is platform independent and works out of the box.
Run BASIC is a powerful, all-in-one Web programming system and application server, designed to make Web programming easy. Its capabilities include the use of the BASIC scripting language, graphics, XML, SQLite database, Cascading Style Sheets, and more. A help file, a tutorial, and example programs are included. This free edition lets you experiment with the Run BASIC system on a single computer.
GetData is a library that provides an API to interface with dirfile databases. The dirfile database format is designed to provide a fast, scalable format for storing and reading binary, synchronously-sampled, time-ordered data. GetData was originally written for the BOOMERanG and BLAST experiments as a data format suitable for use for both quick-look and data reduction. It is now used by many other cosmological and astrophysical experiments including ACT, Planck, Spider, Keck, as well as other projects.
SQLite Diff is a tool for comparing SQLite database schema and data. It is a graphical application that enables developers to easily drag and drop two SQLite databases onto the application to start the comparison process. SQLite Diff uses a high performance in-memory store of both SQLite schemas to perform most comparisons within in a few seconds. The data comparison feature optionally compares each record within the dropped files using the ROWID as the primary key.