Relational Database Design MCQs Flashcards
(31 cards)
What does ER stand for in database design?
o A) Entity Relationship
o B) Entity Relational
o C) Entity Reference
o D) Entity Record
Entity Relationship
Which of the following is a fundamental component of an ER diagram?
o A) Relationships
o B) Attributes
o C) Entities
o D) All of the above
All of the above
In an ER diagram, what does a rectangle represent?
o A) An attribute
o B) A relationship
o C) An entity
o D) A weak entity
An entity
What is the purpose of the diamond shape in an ER diagram?
o A) To represent an entity
o B) To represent an attribute
o C) To represent a relationship
o D) To represent a weak entity
To represent a relationship
In an ER diagram, a solid line typically indicates what type of relationship?
o A) Weak relationship
o B) Strong relationship
o C) Identifying relationship
o D) Non-identifying relationship
Strong relationship
What is an attribute in the context of an ER diagram?
o A) A unique identifier for an entity
o B) A characteristic of an entity
o C) A relationship between entities
o D) A constraint on the entity
A characteristic of an entity
What is the role of a primary key in a relational database?
o A) To uniquely identify each record
o B) To establish relationships between tables
o C) To store duplicate values
o D) To enforce referential integrity
To uniquely identify each record
In EERR (Enhanced Entity-Relationship model), what does a generalization represent?
o A) A hierarchy where a higher-level entity is divided into lower-level entities
o B) A relationship between two entities
o C) A combination of attributes
o D) None of the above
A hierarchy where a higher-level entity is divided into lower-level entities
What is the purpose of using a surrogate key in a relational database?
o A) To create a composite key
o B) To provide a unique identifier that has no business meaning
o C) To replace natural keys
o D) To enforce referential integrity
To provide a unique identifier that has no business meaning
In an ER diagram, how is an attribute that is functionally dependent on another
o A) With a dashed line
o B) With a solid line
o C) With a double oval
o D) With a single oval
With a solid line
Which of the following is NOT a type of relationship in an ER model?
o A) One-to-many
o B) Many-to-many
o C) One-to-zero
o D) One-to-one
One-to-zero
What happens during the transformation of an ER diagram to a relational schema?
o A) Attributes become tables
o B) Entities become attributes
o C) Relationships become tables
o D) All of the above
All of the above
How do you represent an attribute of an entity in a relational schema?
o A) As a table
o B) As a column in the entity’s table
o C) As a relationship
o D) As a foreign key
As a column in the entity’s table
What is the main purpose of normalization in relational database design?
o A) To eliminate data redundancy and improve data integrity
o B) To create more tables
o C) To combine entities
o D) To simplify ER diagrams
To eliminate data redundancy and improve data integrity
How is a composite attribute represented in an ER diagram?
o A) As a rectangle
o B) As a diamond
o C) As an oval with sub-ovals
o D) As a double rectangle
As an oval with sub-ovals
Which of the following is a characteristic of a strong entity?
o A) It does not have a primary key.
o B) It can exist independently of other entities.
o C) It is always represented as a weak entity.
o D) It requires a composite key.
It can exist independently of other entities.
What does a dashed line in an ER diagram typically indicate?
o A) A strong relationship
o B) A weak relationship
o C) A generalization
o D) A multi-valued attribute
A weak relationship
In a relational schema, how is a many-to-many relationship typically resolved?
o A) By creating a new entity that includes attributes from both entities
o B) By adding a foreign key to one of the tables
o C) By using a composite primary key
o D) By merging the two tables
By creating a new entity that includes attributes from both entities
Which of the following best describes a normalization process?
o A) Combining tables to reduce complexity
o B) Organizing data to minimize redundancy
o C) Creating more entities in an ER diagram
o D) Eliminating all relationships
Organizing data to minimize redundancy
What does the term “attribute inheritance” refer to in an Enhanced ER model?
o A) Attributes are lost during mapping.
o B) Subclasses inherit attributes from superclasses.
o C) Attributes cannot be changed.
o D) All entities must have the same attributes.
Subclasses inherit attributes from superclasses.
What is the main purpose of mapping relationships in an ER diagram to a relational schema?
o A) To simplify the design process
o B) To enforce data integrity
o C) To define how entities relate to one another in the database
o D) To generate SQL queries
To define how entities relate to one another in the database
Which of the following is a common representation for a ternary relationship in an ER diagram?
o A) A triangle
o B) A diamond connecting three entities
o C) A rectangle connected by three lines
o D) A dashed rectangle
A diamond connecting three entities
In a relational schema, how are attributes of a weak entity represented?
o A) As foreign keys referencing the strong entity
o B) As primary keys
o C) As unique identifiers
o D) As null values
As foreign keys referencing the strong entity
In an ER diagram, what is the effect of a participation constraint?
o A) It specifies whether all or some entities in a set must participate in a relationship.
o B) It defines the uniqueness of an entity.
o C) It determines the number of attributes in a relationship.
o D) It indicates the strength of the relationship.
It specifies whether all or some entities in a set must participate in a relationship.
