Table of ContentsE/R Entity/Relationship Model E/R Diagram Relationships Relationship Set Example of Relationship Set Multiway Relationships relationship among students, courses, TA's Multiway Relationships relationship among students, courses, TA's (II) Table Question Diagram Table OK What’s Wrong? Attributes Vs. E.S. +Relationships Attributes Vs. E.S. +Relationships (II) Can We Solve (1) by Adding Attributes? Can We Solve (1) by Adding Attributes? (II) ODL Graphically ODL ODL (II) Beers-Bars-Drinkers Example Beers-Bars-Drinkers Example (II) Beers-Bars-Drinkers Example (III) Beers-Bars-Drinkers Example (III) Beers-Bars-Drinkers Example (IV) ODL Type System Limitations on Nesting Multiplicity of Relationships Representation of Many-One Drinkers Have Favorite Beers Drinkers Have Favorite Beers (II) Drinkers Have Favorite Beers (III) One-One Relationships One-One Relationships (II) Attributes on Relationships Shorthand for 3-way Relationship Notes Converting Multiway to 2-Way Converting Multiway to 2-Way (II) Multiway in ODL Needs “Connecting" Class Roles Roles Diagram Roles Diagram (II) Notes Roles in ODL Roles in ODL (II) |
Author: Gary L. Burt
Email: burt@umbc Home Page: www.cs.umbc.edu/~burt |