# Qbe provides some means for the user to interact

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34)QBE provides some means for the user to interact graphically with the database.This is donethrough display of skeleton tables showing the table name and the column names above blankspaces used for entry of query conditions.An example of a QBE table for the relationStudent (sno, sname, age)is given below:What is (are) the expected output(s) from this query?STUDENTSNOSNAMEAGEP.> = 18(a)All student data for student age > = 18(b)Sno, sname for student age > = 18(c)Student age for age > = 18(d)Sno, sname, age for age > = 18(e)Student, sno, sname, age for age > = 18
35)Which of the following is (are) true for relational calculus?
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(c)The existential quantifier states that at least one instance of a particular type ofthing exists.(d)The universal quantifier states that some condition applies to all or to every rowof some type.(e)Relational calculus is based on a branch of mathematical logic called predicatecalculus.36)If CURRENT_DATE is a function, which always returns today’s date, what is the meaning of thefollowing SQL expression that calculates a new date?CURRENT_DATE + INTERVAL '14' DAY
37)Product(Prod_ID)andSales(Sal_ID, Prod_ID)are two relations containing thefollowing data :What is (are) theSal_IDvalues if we apply the relational operator divide (/) onSalesProduct(i.e.Sales/Product)?by
38)With respect to the SQL commands, select the correct statement(s):(a)Data Definition Language (DDL) consists of commands used to define a databaseincluding creating, altering, dropping tables and establishing constraints.(b)Data Manipulation Language (DML) is the set of commands used to maintainand query a database including updating, inserting, modifying and retrieving data.(c)Data Control Language (DCL) commands are used to control a database,including administering features and security of data.(d)To create a database DDL commands are optional, but DML and DCL commandare compulsory.(e)All the commands used in DDL, DML, and DCL end with a colon.

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Term
Fall
Professor
NoProfessor
Tags
Relational model, Lecturer