Active Record connects business objects and database tables to create a persistable domain model where logic and data is presented in one wrapping. It’s an implementation of the object-relational mapping (ORM) pattern in which an object that wraps a row in a database table or view, encapsulates the database access, and adds domain logic on that data.
db.* is a database management system (DBMS) designed to provide powerful, flexible, high-performance capabilities for developing embedded database applications. By combining the network and relational model technologies in a single system, it lets you organize and access information efficiently, regardless of the complexity of the data. The database has a very small footprint and because it is possible to use the network model to store some of the data, it can be very fast. It is also well-documented and quite simple to learn because of its C-based API.
Ingres is a feature rich and robust database (RDBMS) that's free to use, modify, and redistribute. Support is available for a reasonable price if you need it. Ingres supports many programming languages, including Python, Ruby, Java, Perl, C/C++, and more. Ingres has a bit of a learning curve, but once mastered is extremely powerful and highly tunable. It is also very stable and reliable. Ingres is one of a fairly small number of databases providing excellent geospatial features including data types and functions compliant with the Open Geospatial Consortium (OGC) Simple Feature Specification (SFS) for SQL.
RapidMiner (formerly YALE) is a flexible Java environment for knowledge discovery in databases, machine learning, and data mining. Many nestable learning and preprocessing operators (including Weka) are provided. It features an XML-based graphical user interface, a plugin mechanism, and high-dimensional plotting, and provides an easy-to-use extension mechanism that makes it possible to integrate new operators and adapt the system to your personal requirements. A command line version is also included.