Persistence unified
Contents
Unified persistence for Eiffel
This project is about developing a single, integrated and simple persistence framework for Eiffel.
Single because nothing else should be needed to access any kind of persistence services.
Integrated because aims at integrating both the already existing technologies and frameworks, as far as they deliver the intended benefits, and possibly new ones.
Simple because it should be very easy to use, removing all the unnecessary complexity.
A tentative manifesto
The first proposed task is to agree upon a sort of ‘manifesto’ of desirable features of the framework.
Here is a first proposal:
Three abstractions
The framework should provide just three abstractions to the developer: PERSISTENCE_MEDIUM, PERSISTENCE_FORMAT and PERSISTENCE_MANAGER.
Possible specializations of these abstractions could be:
- FILE_MEDIUM, NETWORK_MEDIUM, RELATIONAL_DB_MEDIUM, CUSTOM_MEDIUM, ...
- BINARY_FORMAT, STRING_FORMAT, XML_FORMAT, DADL_FORMAT, CUSTOM_FORMAT, ...
- SERIALIZATION_MANAGER, RDBMS_MANAGER, CUSTOM_MANAGER, ...
Persistence independence
Classes which objects have to be persisted should not be polluted with persistence code, for example adding specific persistence-related attributes or by inhering from some other class that provides persistence services.
- The access to the persistence services should be as uniform as possible. This can be achieved using the XXX_MANAGER class hierarchy that handles access to specific kinds of persistence stores
- The different media should be properly incapsulated. This can be achieved using the XXX_MEDIUM class hierarchy
- The different formats should be properly incapsulated. This can be achieved using the XXX_FORMAT class hierarchy
