The Date::Pcalc Perl module is a direct translation of Steffen Beyer's excellent Date::Calc module from a combination of C and Perl to Perl only. The Perl module does all kinds of date calculations based on the Gregorian calendar (the one used in all western countries today), thereby complying with all relevant norms and standards: ISO/R 2015-1971, DIN 1355 and, to some extent, ISO 8601 (where applicable).
DBPrism is an open source framework to generate dynamic XML from a database. It connects Oracle databases with Apache Cocoon, providing a high performance DBGenerator with functionality such as parallel content aggregation and ESI cache protocol. It also includes a powerlful database oriented CMS built on top of Apache Cocoon2 and DBPrism.
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.
DB_Browser is a CGI tool for developers working with any relational database supported by Perl::DBI. It easily facilitates searching, editing, and adding to tables within a database. While it can be used as a regular interface to database data itself, it works well as a supplemental tool for developers creating their own primary interface.
Dead Link Check (DLC) is a Perl script designed to find information on validity of HTTP references. The script may use/generate a cache file for avoiding redoing network requests if the user wants to check added entries. The script works by reading entries from a file (or a list of links from the command line) and output results in file(s) (or STDOUT). DLC was created as an extension to Public Bookmark Generator (PBM), but can be used on its own.