Methods and apparatus for providing transparent persistent data support to foreign data types

摘要

The present invention teaches a variety of methods, data structures, and apparatus. In a first embodiment of the present invention, an instance of a data type has a data structure including a transient value data field for storing an internalized data format representation of a persistent data associated with the instance and a persistent value data field for storing an externalized data format representation of the persistent data associated with the instance. The data structure provides a capability of maintaining a persistent data associated with the instance within a database in which the data type of the instance is foreign. This includes embodiments in which the database is a relational database or an object oriented database. In some embodiments, the instance is included in a persistent programming language object. A separate embodiment of the present invention teaches a computer system having a central processing unit, a transient computer readable medium accessible by the central processing unit, a persistent computer readable medium accessible by the central processing unit, and an instance of a data type having a data structure stored in the transient computer readable medium. Further implemented on the computer system is a database and a persistent storage manager. The persistent storage manager is operative to manage the database such that the persistent data associated with the instance is maintained within the database. In addition, a number of methods for providing a variety of aspects of transparent persistent data support to instances of persistent foreign data types are disclosed.