Purpose of E/R Model The E/R model allows us to sketch database schema designs. Includes some constraints,but not operations. Designs are pictures called entity- relationship diagrams. Later:convert E/R designs to relational DB designs. 33 Purpose of E/R Model † The E/R model allows us to sketch database schema designs. „ Includes some constraints, but not operations. † Designs are pictures called entity￾relationship diagrams. † Later: convert E/R designs to relational DB designs