Using Queries to Associate Metadata with Data

As relational databases proliferate and become increasingly complex, both in their internal structure and in their interactions with other databases and applications, there is a growing need to associate a variety of metadata with the underlying data. Even though the need has been apparent, a simple, elegant approach to uniformly model and query both data and metadata has been elusive. In this paper, we argue that the relational model augmented with queries as data values is a natural way to uniformly model data, arbitrary metadata and their association.