Er Diagram Cheat Sheet - An attribute a follows from a set of attributes y, if there is an fd x !a such that x y. Web an entity relationship diagram (erd) is a visual representation of different entities within a system and how they. De nition (closure of a set of attributes.
De nition (closure of a set of attributes. Web an entity relationship diagram (erd) is a visual representation of different entities within a system and how they. An attribute a follows from a set of attributes y, if there is an fd x !a such that x y.