Entity Relationship Diagrams (ERDs)

Entity Relationship Diagram (ERD) documentation technique to represent relationship between entities in system. 21

Depends on business rules !! Cardinality represents the numerical mapping between entities: one-to-one one-to-many many-to-many Depends on business rules !! 22

Cardinalities 1 1 Entity Relationship Entity Sales- person Car is assigned Customer Company A 23

Cardinalities 1 M Entity Relationship Entity Sales- person Car is assigned Company B Customer 23

Cardinalities Entity Relationship Entity 1 M Customer places Order 23

Cardinalities M M Entity Relationship Entity Vendor Inventory supplies 23

ERD – Expenditure Cycle

Describe the business rules represented by the cardinalities in the ERD. VENDOR 1 1 M M P.O. M INVENTORY M 1 M M REC. RPT. 1

Add 3 attributes for each entity. VENDOR 1 1 M M P.O. M INVENTORY M 1 M M REC. RPT. 1

3 attributes for each entity. VENDOR 1 M 1 M P.O. M INVENTORY M 1 M M REC. RPT. 1

Modify the ERD, based on the following information: 1 VENDOR The Vendor sends an invoice for each shipment. The invoice is matched to the RR; a Cash Disbursement (CD) is prepared for each invoice. 1 M M M P.O. M INVENTORY 1 M M 1 REC. RPT. 12

VENDOR 1 1 M M P.O. M INVENTORY M 1 M M REC. RPT. 1

Add 3 attributes for each new entity. VENDOR 1 1 M M P.O. M INVENTORY M 1 M M REC. RPT. 1

The End