PostgreSQL

PostgreSQL is an object-oriented relational database management system that comes with two additional tools: PL/Java, an add-on that adds stored procedures, triggers and Java functions to PostgreSQL; and PL/pgSQL, a debugger for the imperative programming language used by this DBMS.

PostgreSQL supports features that include the following: complex queries, foreign keys, triggers, views, transactional integrity and multiversion concurrency control. It is also scalable so any user can extend its operation with new data types, functions, operators, indexing methods and aggregate functions.

PostgreSQL also includes pgAdmin III, an application that allows you to manage such databases visually and which comes with the following features: native access, a powerful tool for querying with support for syntax coloring, a fast datagrid for writing and reading data, access to all Postgree objects, multibyte support, and so on.