WorksheetsSW2- RELATIONS IN DBMS
Total questions: 20
Worksheet time: 10mins
A two-dimensional table of data sometimes is called a:
group
table
er diagram
relation
________ is a component of the relational data model included to specify business rules to maintain the integrity of data when they are manipulated.
Business rule constraint
Data Integrity
Business Integrity
Data Structure
An attribute (or attributes) that uniquely identifies each row in a relation is called a
column
forum field
primary key
duplicate key
An attribute in a relation of a database that serves as the primary key of another relation in the same database is called a:
link attribute
primary key
composite key
foreign key
A primary key that consists of more than one attribute is called a:
foreign key
composite key
multivalued key
primary key
Which of the following are properties of relations?
Each attribute has a unique name.
No two rows in a relation are identical.
There are no multivalued attributes in a relation.
all of the given choices is right
In the figure below, the primary key for "Order Line" is which type of key?
primary key
composite key
foreign key
multivalued key
The entity integrity rule states that:
no primary key attribute can be null.
referential integrity must be maintained across all entities.
each entity must have a primary key.
a primary key must have only one attribute
A domain definition consists of the following components EXCEPT:
domain name
data type
integrity constraint
size
The ________ states that no primary key attribute may be null.
referential integrity constraint
entity integrity rule
partial specialization rule
) range domain rule
A rule that states that each foreign key value must match a primary key value in the other relation is called the:
referential integrity constraint
entity integrity rule
partial specialization rule
range domain rule
When a regular entity type contains a multivalued attribute, one must:
create a single relation with multiple lines for each instance of the multivalued attribute.
create two new relations, one containing the multivalued attribute.
create two new relations, both containing the multivalued attribute.
none of the choices here are correct
In the figure below, what type of relationship do the relations depict?
Strong entity/weak entity
Multivalued
Composite foreign key
One-to-many
In the figure below, what type of relationship do the relations depict?
Strong entity/weak entity
One-to-many
Ternary
Many-to-many
In the figure below, what is depicted?
A one-to-one relationship
A unary relationship
A one-to-many relationship
An associative entity
Referring to the figure below, which of the following is NOT true?
A component is part of an item.
A component is always used in only one item.
A component can be part of an item.
A component may be used in many items.
The figure below is an example of mapping which type of relationship?
FIRST
SECOND
UNARY
TERNARY
What is the mapping binary relationships being discussed in the statement below?
Primary key on the one side becomes a foreign key on the many side
One-to-One
Many-to-Many
One-to-Many
One-to-Optional Many
What is the mapping binary relationships being discussed in the statement below?
Create a new relation with the primary keys of the two entities as its primary key
One-to-One
Many-to-Many
One-to-Many
One-to-Optional Many
What is the mapping binary relationships being discussed in the statement below?
Primary key on mandatory side becomes a foreign key on optional side
One-to-One
Many-to-Many
One-to-Many
One-to-Optional Many
