Relationship Sets to Tables

• In translating a relationship set to a relation, attributes of the relation must include:

  • Keys for each participating entity set (as foreign keys).
    • This set of attributes forms a superkey for the relation.
  • All descriptive attributes.

CREATE TABLE Works_In(

ssn CHAR(1),

did INTEGER,

since DATE,

PRIMARY KEY (ssn, did),

FOREIGN KEY (ssn)

REFERENCES Employees,

FOREIGN KEY (did)

REFERENCES Departments)

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