Athena Framework for Java is a full fledged enterprise object-relational mapping (ORM) framework that employs metadata as mapping configuration. It greatly simplifies Java Web application development by removing the requirement of manual mapping and manual database schema updating. In addition to features like Java object persistence, powerful EJBQL querying execution, and comprehensive code generation, Athena has built-in support for multi-tenancy, which enables developers to build cloud applications easily. Athena can be easily integrated with other libraries like Struts or Spring to provide full stacks of service.
ODB is a compiler-based object-relational mapping (ORM) system for C++. It allows you to persist C++ objects to a relational database without having to deal with tables, columns, or SQL and without manually writing any mapping code. The C++ code that performs the conversion between persistent classes and their database representation is automatically generated by the ODB compiler. The ODB compiler is a real C++ compiler except that instead of producing assembly or machine code, it generates portable C++, which can in turn be compiled by any C++ compiler. ODB is not a framework. It does not dictate how you should write your application. Rather, it is designed to fit into your style and architecture by only handling C++ object persistence and not interfering with any other functionality.
The YB.ORM library aims to simplify writing C++ code that has to deal with SQL databases. The goal is to provide a convenient interface like SQLAlchemy (Python) or Hibernate (Java). The library itself is cross-platform and supports a variety of SQL dialects: SQLite3, MySQL, Postgres, Oracle, and Firebird. Integration with Boost, Qt4, and wxWidgets is built-in. In a typical usage scenario, you would describe your database schema and table relationships in a simple XML-based format, generate SQL code to populate database schema with tables, generate C++ classes, add application-specific logic to the classes, and use these classes in cooperation with the Session object to query objects from the database, create new or modify/delete existing objects, or link and unlink objects using relations. Simple serialization to XML is supported along with connection pooling.
OOS is a C++ object-relational mapping (ORM) framework. It aims to encapsulate all of the database backend functionality and keep it away from the user. One don't have to deal with database backends or SQL statements, nor with mapping of data types or serialization of objects. It provides an STL-like API and one container for all persistent objects - the object store.