Aggregation

Map relationship set R that is aggregated to new table R

Tabular representation of aggregation of R = Tabular representation for relationship R

Relationship set involving aggregation of R is like an entity set whose primary key is the primary key of the table for R

Example

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EnrolledIn constraints:

foreign key ( StudentNum ) references Student
foreign key ( CourseNum ) references Course

CourseAccount constraints:

foreign key ( UserdId ) references Account
foreign key ( StudentNum, CourseNum ) references EnrolledIn