Achieving physical data independence in hypermedia databases

Abstract

As a large amount of hypermedia data is collected the question of storing these data in hypermedia databases arises. One of the problems encountered is how to separate applications from the data so that the same data can be used by many applications and changes to data organization have-besides execution-time-no effect on applications. In conventional databases this problem is solved by the concept of physical data independence. We argue that the concept of physical data independence can be applied beneficially to hypermedia databases, too. So far, while the demand for physical data independence has been voiced in a number of papers, only partial solutions have been proposed. We describe the part of a hypermedia database management system which deals with physical data independence and show how an existing database management system can be extended in this direction. In particular; we present a DataBlade for Ilustra, extending Illustra with physical data independence for images.