Notes on Relationship Diagrams

RelationshipDiagrams.md

Relationship Diagrams Instructor Notes

Objectives

• Explain the difference between data and information
• Explain what an entity relationship diagram is
• Explain why an entity relationship diagram is useful
• Use entity relationship diagrams to model data
• Proactively and reactively normalize data

Explain the difference between data and information

Turn to your neighbor and discuss the difference between data and information.

Explain what an entity relationship diagram is

Turn to your neighbor and define what an entity relationship diagram is. Make sure to describe the features that make up an entity relationship diagram using the key terminology: entity, attribute, associative entity, relationship (cardinality?)

Explain why an entity relationship diagram is useful

Turn to your neighbor and discuss why entity relationship diagrams are useful? Be prepared to share with the class.

Use entity relationship diagrams to model data

Pets

With your neighbors, draw an ERD to represent the relationship between pets entities and species entities.

Then add an owner entities to the diagram.

Then one more entity of your choosing.

Ebay

Draw an ERD to represent a simple e-commerce site like Ebay. Include the following entities:

• Users
• Sellers
• Items
• Orders

Proactively and reactively normalize data

Using the unnormalized data bellow, normalize it and construct an ERD modeling it's relationships.

Over the top solution