ER Modeling Lecture 7 Supplemental Diagrams MBA 8473

Version 1 From Class Notes: (In-Class Exercise 1, Slide 28 from Data Modeling Part 1 Lecture Notes) ER Model places PRODUCT Fills Version 1 relationship related assumptions: 1.1 order has only one product 2.See chat log for other assumptions CUSTOMERORDER 0 o Read as: Product fills Order

Version 2 From Class Notes: (In-Class Exercise 1, Slide 28 from Data Modeling Part 1 Lecture Notes) ER Model places PRODUCT Fills Version 2 relationship related assumptions: 1.1 order has many products 2.Other assumptions same as Version 1 (see chat log) NOTE: For relational model, need to split M:N relationship of Order:Product in this ERD CUSTOMERORDER 0 o

Version 2 (continued) From Class Notes: Splitting M:N relationship of Order:Product for relational model ER Model places ORDERED-PRODUCT Fills CUSTOMERORDER 0 PRODUCT o Note: The M:N relationship from the previous slide has been split into TWO 1:M relationships via an “Intersection Entity” (Ordered-Product). When creating Intersection Entities, think in terms of what occurs when the relationship (in this case a transaction) is consummated. Note: The M:N relationship from the previous slide has been split into TWO 1:M relationships via an “Intersection Entity” (Ordered-Product). When creating Intersection Entities, think in terms of what occurs when the relationship (in this case a transaction) is consummated. Becomes part of

IN CLASS EXERCISE 2, SLIDE 29 from Data Modeling Part 1 Lecture Notes (see chat Log for assumptions) Splitting M:N Relationships ER Model asks for BUSINESS LICENSE TYPE 0 BUSINESSLICENSE TYPEISSUED LICENSE Split this M:N can have 0 Intersection Entity includes Into TWO 1:M relationships via an Intersection Entity