Agenda for Week 1/31 & 2/2. Learn about database design Vocabulary Modeling tool: Entity relationship diagram (ERD) Practical modeling concepts Do database design Practice creating ERD’s Primarily from “draftsman” perspective. Database Design.
Examples: Binary relationship with explicit relationship symbol
Examples: Binary relationship without explicit relationship symbol
Examples of Unary Relationships
Example of a ternary relationship
Example of an n-ary relationship
Example of a logical ERD
Example of a Physical ERD
Return to First Week Exercise Data (condensed)
Possible Solution #1: Put the quantity ordered (qty_ordered) in the item entity, and create a concatenated primary key
Possible solution#1: Results in redundant data for item name, cost and sell price
Possible solution #2: Uses an intersection entity (Orderline) to avoid redundant data.
Possible Solution #2: Another table, but less data redundancy