Which of the following best describes the query ?
A. Finds the names of all instructors whose department is in the Watson building.
B. Finds the names of all department is in the Watson building.
C. Finds the name of the dapartment whose instructor and building is Watson.
D. Returns the building name of all the departments.
Answer:A
Which of the following best describes the query ?
A. Finds the names of all instructors whose department is in the Watson building. B. Finds the names of all department is in the Watson building. C. Finds the name of the dapartment whose instructor and building is Watson. D. Returns the building name of all the departments.
Explanation:This query has two “there exists” clauses in our tuple-relational-calculus expression, connected by and (∧). 4. Which of the following symbol is used in the place of except ?