object projection views in the dynamic relational model
User views in a relational database obtained through a single projection ("projection views") are considered in a new framework. Specifically, such views where each tuple in the view represents an object ("object projection views") are studied using the dynamic relational model of [V1,V2], which captures the evolution of the database through consecutive updates. Attribute sets which yield object projection views are characterized using the static and dynamic functional dependencies satisfied by the database. Object projection views are then described using the static and dynamic fd's "inherited" from the original database, and the notion of age-closure [V1]. Finally, the impact of dynamic constraints on the view update problem is studied in a limited context. The paper demonstrates that new, useful information about views can be obtained by looking at the evolution of the database as captured by the dynamic relational model.
object project views dynamic relation model user relational database database evolution update attributes yield functional dependency constraint context paper informal  framework  age