# Question: Let the following relation schemas be given R A B

Let the following relation schemas be given:

R = (A, B, C)

S = (D, E, F) Let relations r(R) ands(S) be given. Give expressions in QBE, and Data log equivalent to each of the following queries:

a. IIA(r)

b. σB =17 (r)

c. r × sd. IIA,F (σC =D(r × s))

R = (A, B, C)

S = (D, E, F) Let relations r(R) ands(S) be given. Give expressions in QBE, and Data log equivalent to each of the following queries:

a. IIA(r)

b. σB =17 (r)

c. r × sd. IIA,F (σC =D(r × s))

**View Solution:**## Answer to relevant Questions

Let R = (A, B, C), and let r1 and r2 both be relations on schema R. Give expressions in QBE, and Datalog equivalent to each of the following queries: a. r1 ∪ r2 b. r1 ∩ r2 c. r1 − r2 d. IIAB (r1) 1 IIBC ...Complete the SQL DDL definition of the bank database of Figure to include the relations loan andborrower.Consider a view branch-cust defined as follows: create view branch-cust as select branch-name, customer-name from depositor, account where depositor.account-number = account.account-number Suppose that the view is ...Perhaps the most important data items in any database system are the passwords that control access to the database. Suggest a scheme for the secure storage of passwords.Be sure that your scheme allows the systemto test ...Use Armstrong’s axioms to prove the soundness of the decomposition rule.Post your question