If we had another relation, staff, which was union compatible with faculty, what would the following expression return for a result?Πempno (Staff ⋃ Instructor)Select one:a.The employee number of every staff employee and every instructorb.Every employee who is either a member of the staff or an instructorc.All tuples of the instructor relation along with all tuples of the staff relationd.The employee number of all rows in the staff and in the instructor relations
Question
If we had another relation, staff, which was union compatible with faculty, what would the following expression return for a result?Πempno (Staff ⋃ Instructor)Select one:a.The employee number of every staff employee and every instructorb.Every employee who is either a member of the staff or an instructorc.All tuples of the instructor relation along with all tuples of the staff relationd.The employee number of all rows in the staff and in the instructor relations
Solution 1
The correct answer is d. The employee number of all rows in the staff and in the instructor relations.
Here's why:
The expression Πempno (Staff ⋃ Instructor) is using the projection operator (Π) and the union operator (⋃) in relational algebra.
The union operator (⋃) combines the tuples of two relations (Staff and Instructor in this case) that are union compatible (i.e., have the same number of attributes and the corresponding attributes have the same domain or data type).
The projection operator (Π) then selects only the specified attribute(s) (empno in this case) from the combined relation.
So, the expression Πempno (Staff ⋃ Instructor) will return the employee number (empno) of all rows in both the Staff and Instructor relations.
Solution 2
The correct answer is d. The employee number of all rows in the staff and in the instructor relations.
Here's why:
The expression Πempno (Staff ⋃ Instructor) is using the projection operator (Π) and the union operator (⋃) in relational algebra.
The union operator (⋃) combines the tuples of two relations (Staff and Instructor) that are union compatible (
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