Database Reference
In-Depth Information
5.
A record is to a file:
{01}
a.
What a mouse is to a computer
b.
What a tuple is to a relation
c.
What a procedure is to a program
d.
What peach is to a fruit salad
6.
Cardinality of a relation refers to:
{01}
a.
The age (in months) of the relation
b.
The sexual orientation of parties in the relation
c.
The number of tuples in the relation
d.
None of the above
7.
A foreign key may be defined as:
{01}
a.
An attribute or combination of attributes that uniquely
identify tuples of a relation
b.
An attribute or combination of attributes that ought not
to have been included in a relation
c.
An attribute that may contain null values
d.
An attribute or combination of attributes of a relation R1
that forms the primary key in some other relation R2
8.
Let R1[A,B,C] and R2[C,D,E] be two relations with R1.C being
defined on the same domain as R2.C. Assume further that the
primary key of R1 is A and the primary key of R2 is C. Which of
the following statements are valid?
{02}
a.
SELECT * FROM R1, R2 WHERE R1.C = R2.C
b.
SELECT * FROM R1, R2 WHERE R1.C = R2.D
c.
There is a M:M relationship between R1 and R2
d.
There is a 1:M relationship between R2 and R1
9.
Based on the principle of data independence, which of the
following can be concluded?
{02}
a.
One can decompose a relation into smaller projections in
any way he/she chooses
b.
Structural changes to a database should not affect the
application programs that access the database
