# Question

Let R = (A, B) and S = (A, C), and let r(R) and s(S) be relations. Write relational-algebra expressions equivalent to the following domain-relationalcalculus expressions:

a. {< a > | ∃ b (< a, b >∈ r ∧ b = 17)}

b. {< a, b, c > | < a, b >∈ r ∧ < a, c >∈ s}

c. {< a > | ∃ b (< a, b >∈ r) ∨ ∀c (∃ d (< d, c >∈ s) ⇒ < a, c >∈ s)}

d. {< a > | ∃ c (< a, c > ∈ s ∧ ∃ b1, b2 (< a, b1 > ∈ r ∧ < c, b2 > ∈ r ∧ b1 > b2))}

a. {< a > | ∃ b (< a, b >∈ r ∧ b = 17)}

b. {< a, b, c > | < a, b >∈ r ∧ < a, c >∈ s}

c. {< a > | ∃ b (< a, b >∈ r) ∨ ∀c (∃ d (< d, c >∈ s) ⇒ < a, c >∈ s)}

d. {< a > | ∃ c (< a, c > ∈ s ∧ ∃ b1, b2 (< a, b1 > ∈ r ∧ < c, b2 > ∈ r ∧ b1 > b2))}

## Answer to relevant Questions

Let R = (A, B) and S = (A, C), and let r(R) and s(S) be relations. Using the special constant null, write tuple-relational-calculus expressions equivalent to each of the following: a. r 1 s b. r 1 s c. r 1 sConsider the relational database of Figure. Give an expression in SQL for each of the following queries.a. Modify the database so that Jones now lives in Newtown.b. Give all employees of First Bank Corporation a 10 percent ...Write an SQL query, without using a with clause, to find all branches where the total account deposit is less than the average total account deposit at all branches,a. Using a nested query in the from clauser.b. Using a ...Consider the employee database of Figure. Give expressions in QBE, and Datalog for each of the following queries:a. Find the names of all employees who work for First Bank Corporation.b. Find the names and cities of ...Complete the SQL DDL definition of the bank database of Figure to include the relations loan andborrower.Post your question

0