Validity Queries and Completeness Queries

The concepts of validity and completeness are defined in terms of relationship between a correct representation of the real world and the representation of the real world which is stored in a database. Here a database is understood as a Relational database, that is, a set of atomic facts. It is assumed that some users can guarantee that some parts of the database are valid, and other parts are complete. From this information, for a given standard query, are characterized a subset of the answer to the standard query which is valid, and a superset of the answer which is complete. It is guaranteed that the correct answer is bounded up and down by these two sets.