In software engineering, an Entity-Relationship Model (ERM) is an abstract and conceptual representation of data. Entity-relationship modeling is a database modeling method, used to produce a type of conceptual schema or semantic data model of a system, often a relational database, and its requirements in a top-down fashion. Diagrams created using this process are called entity-relationship
. diagrams, or ER diagrams or ERDs for short. If you would like to know moe about entity relationship diagrams library visit http://erw.dsi.unimi.it/diagram.html