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.
The eGenix mxODBC Zope Database Adapter (Zope DA) allows you to easily connect your Zope installation to just about any database backend. Unlike Zope's ZODBC Zope DA, the mxODBC Zope DA works on Windows, Linux, and Solaris using the same interface. It implements thread-safe connection pooling and multiple physical connects per logical Zope connection. You can safely run Z SQL Methods in parallel, achieving much better performance than ZODBC Zope DA or similar database adapters under heavy load. This makes it ideal for deployment in clusters and hosting environments where stability and high performance are a priority.
Divmod Axiom is an object-relational database backed by SQLite, the goal of which is to provide an efficient, non-SQL interface to an existing relational database manager. It provides support for common Twisted practices: an Axiom store is also a Twisted IServiceCollection provider, and an implementation of Twisted's IRealm interface is provided. It makes heavy use of plugins and includes a wall-clock scheduler.
Y Object Database Adapter (YODA) is an environment for creating and running network accessible applications. It can permanently store objects of any type and complexity, and supports attributes of most types (with the exception of only a few Python types, such as thread locks). It can be extended with YODA- server applications, and an application compiler and loader are provided.