Berkeley DB (libdb) is a programmatic toolkit that provides embedded database support for both traditional and client/server applications. It includes b+tree, queue, extended linear hashing, fixed, and variable-length record access methods, transactions, locking, logging, shared memory caching, database recovery, and replication for highly available systems. DB supports C, C++, C#, Java, PHP, and Perl APIs. It supports key-value pair (NoSQL), SQL, and Java Object formatted data. It is available for a wide variety of Unix platforms as well as QNX, Android, Mac OS X, and several varieties of Windows.
CodeBase is a high-speed xBASE compatible database engine for C/C++, Visual Basic, Delphi & Java programmers. You can use CodeBase to write high performance database applications that are multi-user compatible with FoxPro, dBASE and Clipper, create anything from a Java applet to a full-blown Windows database application to a simple DOS utility, write scalable applications that can be deployed as single-user, multi-user or client/server, all without changing any of your source code, and port your applications to Windows, DOS, UNIX, OS/2, and Macintosh. There's a free 30-Day Test Drive option available. CodeBase is available for every major operating system including Windows XP, 2000, 9x, NT, CE, DOS, OS/2, Macintosh, and a variety of Linux and UNIX platforms including Solaris, SunOS, HP/UX, AIX, SCO, and others.
db4o is an object database for Java and all .NET environments. Its features include ACID transactions, automatic class schema recognition, query-by-example, a S.O.D.A. object querying API, native queries, LINQ support on .NET, callback methods, memory files, cascade-on-delete, multi-threaded access, and Java Webstart and servlet support.
MUSCLE (Multi User Server Client Linking Environment) is an N-way messaging server and networking API. It includes client-side networking APIs for various languages, including C, C++, C#, Delphi, Java, and Python. MUSCLE lets programs communicate over a network via streams of serialized Message objects. The included server program ("muscled") lets its clients message each other and store information in its server-side hierarchical database. The database supports flexible queries via hierarchical wildcarding, and "live" updates via a subscription mechanism.
Ice is a modern alternative to object middleware such as CORBA or COM/DCOM/COM+. It is easy to learn, yet provides a powerful network infrastructure for demanding technical applications. It features an object-oriented specification language, easy to use C++ and Java mappings, a highly efficient protocol (including protocol compression), asynchronous method invocation and dispatch, dynamic transport plug-ins, TCP/IP and UDP/IP support, SSL-based security, a firewall solution, and much more.
Bugzproxy is a C# client library for the upcoming Bugzilla Bugtracker WebService interface (part of Bugzilla 3.0). It provides an OO access to a Bugzilla server. The aim of Bugzproxy is to allow easy building of various clients that facilitate the integration of Bugzilla into the various C# tool chains. As the project's aim is to provide an efficient and intuitive OO API, the API probably will change in future revisions.