This question has 2 parts. All parts refer to shema described below where key fi

Question

This question has 2 parts. All parts refer to shema described below where key fields are underlined, and the domain of each field is listed after the field name. Suppliers Parts Catalog State what the following queries compute. Your answer should express the semantics of the queries with the vocabulary of a person who has no knowledge of relational algebra. With other words your answers should not be a translation of the query to an English statement that replaces the operators' names. Something such as "a projection over sname of a projection over sname of a projection of sid of .." will not be accepted as a correct answer. A single sentence is expected as an answer to this question. ((pi_pid, sid Catalog) divided (pi_sid Suppliers)) U pi_pid Parts - pi_pid(Parts Catalog) rho(R1, catalog) rho(R2, Catalog)^pi(R1.pid(sigma R1.pid = R2. pid R1.sid R2 sid(R1 times R2))

Explanation / Answer

part 1)Either Project (pid,sid from Catalog,sid from Suppliers) or project pid from Parts or both which is not the pid present in parts and catalog.

part2)
rename Catalog as R1
rename catalog as R2
Project pid from R1 where pid of R1=pid of R2 and sid of R1 is not equal to sid of R2 form the the cartesian product of R1 and R2

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