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Consider the following two tables and four queries in SQL. Book (isbn, bname), Stock (isbn, copies) Query 1: SELECT B.isbn, S.copies FROM Book B INNER JOIN Stock S ON B.isbn = S.isbn;   Query 2: SELECT B.isbn, S.copies FROM Book B LEFT OUTER JOIN Stock S ON B.isbn = S.isbn; Query 3: SELECT B.isbn, S.copies FROM Book B RIGHT OUTER JOIN Stock S ON B.isbn = S.isbn;   Query 4: SELECT B.isbn, S.copies FROM Book B FULL OUTER JOIN Stock S ON B.isbn = S.isbn;   Which one of the queries above is certain to have an output that is a superset of the outputs of the other three queries?
For any two languages L1 and L2 such that L1 is context-free and L2 is recursively enumerable but not recursive, which of the following is/are necessarily true? I. L̅1 (complement of L1) is recursive II. L̅2 (complement of L2) is recursive III. L̅1 is context-free IV. L̅1 ∪ L2 is recursively enumerable
Assume statements S1 and S2 defined as: S1: L2-L1 is recursive enumerable where L1 and L2 are recursive and recursive enumerable respectively. S2: The set of all Turing machines is countable. Which of the following is true?
Consider a database that has the relation schemas EMP(EmpId, EmpName, DeptId), and DEPT(DeptName, DeptId) Note that the deptId can be permitted to be NULL in the relation EMP. Consider the following queries on the database expressed in tuple relational calculus. (I) { t |∃u ∈ EMP(tEmpName] = u[EmpName] ∧ ∀ v∈ DEPT(t[DeptId] ≠ v[DeptId]))} (II) {t |∃ u ∈ EMP(t[EmpName] = u[EmpName] ∧ ∃ v ∈ DEPT(t[DeptId] ≠ v[DeptId]))} (III) {t | ∃ u∈ EMP(t[EmpName] = u[EmpName] ∧ ∃ v ∈ DEPT(t[DeptId] = v[DeptId]))} Which of the above queries are safe?
Two processes X and Y need to access a critical section. Consider the following synchronization construct used by both the processes Process ? /* other code for process ? */ while(true) { varP = true; while(varQ == true) { /* Critical Section */ varP = false; } } /* other code for process ?? */   Process ? /* other code for process ? */ while(true) { varQ = true; while(varP == true) { /* Critical Section */ varQ = false; } } /* other code for process ? */   Here, varP and varQ are shared variables and both are initialized to false. Which one of the following statements is true?
Consider the following statements.
1. All valid arguments contain only true premises and a true conclusion.
2. Some valid arguments contain only false propositions - false premises and a true conclusion.
3. All valid arguments contain only false propositions all premises are false, conclusion is false as well.
Which of the above statements is correct?
Which of the following statements are true/false?
1. No child will work for more than four hours.
2. No child will work more than seven hours in a day including the rest interval.
3. No child will be permitted or required to work between 7 P.M. and 8 A.M.
4. No child will be required or permitted to work overtime.
Which of the following statement(s) is/are FALSE? (i) There exists a recursively enumerable language whose complement is not recursively enumerable. (ii) If a language L is recursive, then its complement is NOT recursive.
You are the administrator of a SQL Server 2000 computer. The server contains a database named FinanceData that is used by a client/server application. Each employee has a SQL Server login that the application uses to access the server.Your company hires a new employee named Andrew. You create a SQL Server login named Andrew. You also create a database user named Andrew in the database and grant the database user full permissions in the database.Whenever Andrew runs the client/server application, he receives the following error message: "Invalid object name." Andrew also reports that he cannot access the database by using the application.You need to ensure that Andrew can use the application. Which Transact-SQL statement should you execute?
Which of the following statements are TRUE? I. Top-down parsers are equipped to handle left recursive grammar. II. LALR parser is more powerful than an SLR parser. III. Recursive descent parsing is an example of top-down parsing.