Schema Evolution publication categorizer

The evolution of an information system is reflected in data modeling by database reorganization. Entity-Relationship (ER) consistency expresses the capability of relational databases to model information oriented systems. A relational schema consisting of relational schemes, together with key and inclusion dependencies, is said to be ER-consistent if it complies with an entity-relationship structure, meaning that it is representableby an ER-Diagram. For ER- consistent schemas the basic restructuring manipulations are the addition and removal of relation schemes, coupled with the modification of the key and inclusion dependencies. Recently we have defined a set of incremental and reversible schema restructuring manipulations as the translates of a set of vertex-oriented ER-Diagram transformations. For non-empty database states the schema restructuring manipulations must be associated with state mappings, and this leads us to the definition of database reorganization operations; database reorganization operations consist of compatible pairs of incremental restructuring manipulations and entity-bounded state mappings. For the specification of ER-consistent database state mappings, we propose an Entity-Relationship Calculus.