How many distinct tuples are there in a relation instance with cardinality 22 ?
22
11
1
none
Which of the following operations need the participating relations to be union compatible ?
UNION
INTERSECTION
SET DIFFERENCE
All of the above
Abstraction of the database can be viewed as
two levels
four levels
three levels
one level
A file manipulation command that extracts some of the records from a file is called
SELECT
PROJECT
JOIN
PRODUCT
Data independence means
data is defined separately and not included in programs
programs are not dependent on the physical attributes of data
programs are not dependent on the logical attributes of data
both 2 and 3
A relational database developer refers to a record as
criteria
relation
tuple
attribute
Cartesian product in relational algebra is
a unary operator
a binary operator
a ternary operator
not defined
In a table Employee Emp- code, Pan_ no are the candidate keys. If Emp_ code is taken as the primary key then Pan_ no is _________ key.
candidate key
alternate key
primary key
foreign key
The person who interact the database through query language is called
DBA
Application programmers
Sophisticated users
Naive user
An instance of relational schema R (A,B,C) has distinct values of A including NULL values. Which one of the following is true?
A is a candidate key
A is not a candidate key
A is a primary key
Both a and c
