Answer to Question #93469 in Databases | SQL | Oracle | MS Access for Mokete

Question

For the relations s and r in your study manual of our chapter 2 (i.e., joining two relations), suppose we type a collection of relational algebra queries, and get the following results. A B C D E A 2 a 10 B b 2 a 10 b Please explain how this happened? If you think this result could happen in practice, please write the corresponding relational algebra queries; otherwise, please explain why.

Answer 1

It is not possible to answer this question because two collections from the study manual are unknown, i. e. the set of study relations and the set of study algebra operations, BUT it is hard to believe that a tuple will contain the attribute names after executing the queries, i. e. the values 'A' or 'B', if s and r don't have a tuple with these values.