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ER Modeling Lecture 7 Supplemental Diagrams

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. CUSTOMER. places. ORDER. 0. o. Fills. Read as: Product fills Order. Version 1 relationship related assumptions:

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ER Modeling Lecture 7 Supplemental Diagrams

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  1. ER Modeling Lecture 7 Supplemental Diagrams MBA 8473

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

  3. Version 2 From Class Notes: (In-Class Exercise 1, Slide 28 from Data Modeling Part 1 Lecture Notes) ER Model CUSTOMER places ORDER 0 o Fills • Version 2 relationship related assumptions: • 1 order has many products • 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 PRODUCT

  4. Version 2 (continued) From Class Notes: Splitting M:N relationshipof Order:Product for relational model ER Model CUSTOMER places ORDER 0 Fills ORDERED-PRODUCT 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. o Becomes part of PRODUCT

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

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