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.
Berkeley DB XML is a native XML database engine for use within your product. Made available as a C++ library with language bindings for Java, Perl, Python, PHP, and Tcl, it integrates directly into your application (it is not a standalone database server). It provides XQuery access into a database of document containers. XML documents are stored and indexed in their native format using Berkeley DB as the transactional database engine.
Ellogon is a multi-lingual, cross-platform, general-purpose language engineering environment, developed in order to aid both researchers who are doing research in computational linguistics, as well as companies who produce and deliver language engineering systems. As a language engineering platform, it offers an extensive set of facilities, including tools for processing and visualising textual/HTML/XML data and associated linguistic information, support for lexical resources (like creating and embedding lexicons), tools for creating annotated corpora, accessing databases, comparing annotated data, or transforming linguistic information into vectors for use with various machine learning algorithms.
GNU Ferret (formerly known as GerWin) is a free entity relationship and reverse engineering tool. It aids you in creating data models and implementing them in a relational database. You can draw your data model via an entity-relation diagram, generate the tables from it (another graphical diagram), and then generate the SQL that creates such relational tables. Several SQL dialects are supported (for most popular free software database systems) and it is very easy to patch the sources to support more.
NaviServer is a versatile multiprotocol server originally based on AOLserver . It can be easily extended in either C or Tcl to create interesting Web sites and services. Main features include high performance multithreaded architecture, massive scalability and extensible approach, many modules, interpreted config file during startup, dynamic pages (ADP) in TCL, caching functions (static files and TCL byte code), pooled database connections, thread global arrays, introspection commands, mass virtual hosting that does not require server restart, a watchdog that restarts failed servers automatically, a telnet control port, efficient handling of down-/uploads, real-time upload progress/statistics, and more.
OpenIsis provides a library and tools to access CDS/ISIS databases, which are mostly used for bibliographic data (ISO2709, Z39.50) but also well suited for other catalogues due to the very flexible indexing mechanism. Based on a C library, there are also bindings for Perl and Java (Tcl to come).
Qbib is a bibliography management system based on Qddb. Qbib's features include the ability to import and export BibTeX .bib files and handle all standard and most common fields as well as @string translation, it can import .aux files to search results for quick export or review, and can automatically generate unique citation keys. It has a friendly user-interface and mandatory/optional fields for each BibTeX entry type. It has custom export options including author format and selection of fields to export and supports custom keyboard traversal. Qbib can also keep track of URLs, reviews, abstracts, and other important information about your references.