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Entity Relationship Diagrams (ERDs)

Entity Relationship Diagrams (ERDs). Entity Relationship Diagram (ERD). documentation technique to represent relationship between entities in system . Depends on business rules !!. Cardinality. represents the numerical mapping between entities: one-to-one one-to-many many-to-many.

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Entity Relationship Diagrams (ERDs)

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  1. Entity Relationship Diagrams (ERDs)

  2. Entity Relationship Diagram (ERD) documentation technique to represent relationship between entitiesin system.

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

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

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

  6. Cardinalities Entity Relationship Entity 1 M places Order Customer

  7. Cardinalities Entity Relationship Entity M M Vendor Inventory supplies

  8. ERD – Expenditure Cycle

  9. 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

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

  11. 3 attributes for each entity. VENDOR 1 M 1 M P.O. M INVENTORY M 1 M M REC. RPT. 1

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

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

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

  15. The End

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