Entity Relationship Diagram (Pat II)

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Mapping Binary Relationships

One to one Relationship 
  • Partial participation (Partial participation is represented by single lines.)
          Not every professor teaches every student. Every student is not learnt by every professor.

           Relational Mapping

                                                                 Professor ( Name , Phone , Address )
                                                                                     ↑FK
           Course   (CourseId , CourseName , Credits , Name)



  • Total Participation (Total participation is represented by double lines.)
           Every professor teaches every student. Every student is learnt by every professor





          Relational Mapping
          
          Professor (Name , Phone , Address , CourseId , CourseName , Credits)


One to many Relationship (Partial participation)

          Relational Mapping

                                               Customer (CustID , CustName)
                                                                     ↑ FK
          Loan (LoanNum , LoanAmount , CustID)


Many to Many Relationship



          Relational Mapping

          Employee ( ENumber  , EName , Salary)
          Project ( Number , Name)
          Employee_Project (ENumber  ,Number , Name , EName , Salary)
          





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