This set of Advanced Database Management System Multiple Choice Questions and Answers (MCQs) focuses on “Data Models:Entity Relationship Model ”.
PRACTICE IT NOW TO SHARPEN YOUR CONCEPT AND KNOWLEDGE
1. An Entity is a________________
- Relationship model
- Relational Model
- Object having same Value
- Object in the real world distinguishable from all other objects
For example each person in an enterprise is an entity, an entity has a set of properties, and value for some set of properties may uniquely identify an entity.
2. __________is a set of entities of same type that share the same properties or attributes.
- Attributes set
- Relationship Set
- Entity Set
- Property set
For example the set of all persons who are customers at Shopping mall can be defined as the entity set customer.
3. An entity is represented by set of ___________
- Attributes
- Relationship
- Model
- None of the above
Attributes are descriptive properties possessed by each members of an entity set. the designation of an attributes for an entity set expresses that the database stores similar information concerning each entity in the entity set. Each entity has a value for each of its attributes
4. For each attributes, there is set of permitted values called______
- Key set
- Value Set
- Domain
- B and C
For example the domain of the attribute customer name might be the set of all strings of certain length .
5. In a Entity sets Customer and Loan, an Attribute name consisting of first-name ,middle-name, and last-name. An Attribute name is _______
- Simple Attribute
- Composite Attribute
- Single-Valued Attributes
- Multi-valued Attributes
Simple attributes cannot be divided into sub parts on the other hand composite attributes can be divided into subparts.
6. For example Loan-number attribute for a specific loan entity set is referred to as
- Simple Attribute
- Composite Attribute
- Single Valued Attributes
- Multi-valued Attributes
Loan number has a single value for a particular loan entity .
7. Consider an employee entity set with the attribute phone-number, attribute phone-number is a ________
- Simple Attribute
- Composite Attribute
- Single Valued Attributes
- Multi-valued Attributes
An Employee may have zero, one or several phone numbers and different employees may have different numbers of phones.
8. For example, the customer entity set has an attribute loan-taken, which represents how many loans a customer has from the bank, the attribute loan-taken is______
- Derived Attribute
- Composite Attribute
- Single Valued Attributes
- Multi-valued Attributes
The value for this type of attributes can be derived from the values of other related attributes or entities; we can derive the value for this attribute by counting the numbers of loan entities associated with that customer.
9. An Attribute takes a ________value when an entity does not have a value for it.
- Zero
- 0
- Null
- Not Applicable
The Null value may indicate not applicable that is that the value does not exist for the entity, for example one may have no last name ,Null can also designates that an attribute value is not known or may be missing.
10. A______is a set of relationships of the same type among several entities
- Key set
- Value Set
- Domain
- Relationship
Consider the two entities sets customer and loan, we define the relationship set borrower to denote the association between customers and the bank loans that the customers have.
11. The Relationship sets that involve two entity sets in known as___
- Unary Relationship set
- Binary Relationship set
- Ternary Relationship set
- None of the above
12. The number of Entity sets that participate in a relationship set is know as ____________ of Relationship
- Cardinality Ratio
- Mapping Cardinality
- Degree
- Participate
The number of entity sets that participate in a relationship set is known as the degree of relationship set. A binary relationship set is of degree 2; a ternary relationship set is of degree 3.
