DirtBike Order Database– ER Diagram Prepared by (Rahul Dhami) Fall 2012

Step 1: Define Entity Classes and Primary Keys Step 2: Define Relationships Among Entity Classes Step 3: Define Fields for each Relationship Step 4: Create Database Designing Databases with Entity Relationship Diagrams

Entity ClassPrimary Key CustomerCustomer ID OrderOrder ID ProductProduct ID DistributorDistributor ID Step 1: Define Entity Classes and Primary Keys Business Rules Each order is made by a single customer Each customer can have multiple orders Each customer can have on order Customers can be in your database without any orders Products can be listed in your database but not purchased Orders cannot be blank Orders can have more than one (multiple) products A distributor can supply multiple products A distributor has to supply at least one product Each product has to have a distributor

E-R Diagrams Use 5 symbols 1.Rectangle – entity class 2.Dotted line – relationship 3.| - single relationship 4.0 – zero/optional relationship 5.Crow’s foot (  ) – multiple relationship

PRODUCT CUSTOMER ORDER Step 2: Define Relationships Among Entity Classes DISTRIBUTOR Detailed Orders

Step 3: Define Fields for each Relationship Customer IDLastNameFirstNameAddressCityStateZipPhone ENTITY Product IDProduct Name ManufacturerMSRPIgnitionWeightQOHDistributor ID Product Order IDCustomer IDOrder Date Order Distributor IDDistributo r Order IDProduct IDQuantity Detailed Orders

Step 4: Create Database (At this point we will begin working with our DBMS system, which will be Microsoft Access)