Umar Erd

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Entity Relationship Diagram

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Umar Erd

  1. 1. Entity Relationship Diagram Presented by: Muhammad umer Bs(cs) 4th (b)
  2. 2. Entity relationship diagram * In 1976 Peter Chen was developed ERD * Introduce by Charles Bachman * A Graphical Representation * A Semantic Data model
  3. 3. COMPONENTS OF ERD * Data objects * Data attributes * Relationship
  4. 4. TYPES OF RELATIONSHIP * One to One * One to Many * Many to Many
  5. 5. ONE TO ONE ROOF COVERS COVERD BY BUILDING
  6. 6. ONE TO MANY EMPLOYEE WORK IN HAS DEPARTMENT
  7. 7. MANY TO MANY EQUIPMENT ALLOCATED TO ALLOCATED PROJECT
  8. 8. CARDINALITY & MODALITY * Cardinality: Express the maximum number of relationships * Modality: Express whether the relationships is optional or mandatory
  9. 9. THANK YOU

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