Qbe provides some means for the user to interact

34) QBE provides some means for the user to interact graphically with the database. This is done
through display of skeleton tables showing the table name and the column names above blank
spaces used for entry of query conditions. An example of a QBE table for the relation
Student (sno, sname, age)
is given below:
What is (are) the expected output(s) from this query?
STUDENT SNO SNAME AGE
P. > = 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 of
thing exists.
(d) The universal quantifier states that some condition applies to all or to every row
of some type.
(e) Relational calculus is based on a branch of mathematical logic called predicate
calculus.
36) If CURRENT_DATE is a function, which always returns today’s date, what is the meaning of the
following SQL expression that calculates a new date?
CURRENT_DATE + INTERVAL '14' DAY
37) Product(Prod_ID) and Sales(Sal_ID, Prod_ID) are two relations containing the
following data :
What is (are) the Sal_ID values if we apply the relational operator divide (/) on Sales
Product (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 database
including creating, altering, dropping tables and establishing constraints.
(b) Data Manipulation Language (DML) is the set of commands used to maintain
and 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 command
are compulsory.
(e) All the commands used in DDL, DML, and DCL end with a colon.