Redland is a set of C libraries providing a high-level API for the Resource Description Framework (RDF), allowing it to be stored, parsed, serialized, queried, and manipulated. It has an object-based, modular design and comes with detailed reference documentation and examples. Redland supports all RDF vocabularies such as FOAF, RSS 1.0, Dublin Core, DOAP, and OWL, the query languages SPARQL and RDQL, and all RDF syntaxes including Turtle, RDF/XML, RDF/JSON, RSS, Atom, RDFa, and GRDDL.
mysqldiff is a Perl script which compares the data structures (i.e. table definitions) of two MySQL databases and returns the differences as a sequence of MySQL commands suitable for piping into mysql which will transform the structure of the first database to be identical to that of the second (c.f. diff and patch). Database structures can be compared whether they are files containing table definitions or existing databases, local or remote.
phpPgAdmin is a fully functional PHP-based administration package for PostgreSQL. It has all the basic functionality you need to completely administer a PosgreSQL server and/or database, including the ability to administer views, sequences, stored procedures, and triggers. Features include the ability to create and drop databases; create, copy, drop, and alter tables/views/sequences/functions/triggers; edit and add fields (to the extent Postgres allows); execute any SQL-statement, even batch-queries; manage keys on fields; create and read dumps of database and tables; and administer one single database, multiple servers, and Postgres users/groups.
PostgreSQL is a robust relational database system with over 25 years of active development that runs on all major operating systems. It is fully ACID compliant, and has full support for foreign keys, joins, views, triggers, and stored procedures (in multiple languages). It includes most SQL92 and SQL99 data types, including INTEGER, NUMERIC, BOOLEAN, CHAR, VARCHAR, DATE, INTERVAL, and TIMESTAMP. It also supports storage of binary large objects, including pictures, sounds, or video. It has native programming interfaces for C/C++, Java, .Net, Perl, Python, Ruby, Tcl, and ODBC, among others, and exceptional documentation.
HyperSQL is like the doxygen program with Javadoc added, but for SQL. It hypermaps SQL views, packages, procedures, and functions to HTML source code listings, and it shows all the code locations where these are used. You can use JavaDoc-style comments for documentation and even embed UnitTests with them.