The inference problem for template dependencies

摘要

A template dependency is a formalized integrity constraint on a relational database, stating that whenever tuples exist in the database that agree on certain attributes, an additional tuple must also be present that agrees with the others in a specified way. It is here shown that the inference problem for template dependencies is undecidable, that is, there can be no algorithm for determining whether a given dependency is a logical consequence of a given finite set of dependencies. The undecidability result holds whether or not databases are considered to be necessarily finite.