Q. In an ER model, how is a one-to-many relationship typically represented?
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A.
With a single line connecting two entities
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B.
With a crow's foot notation
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C.
With a dashed line
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D.
With a double line
Solution
A one-to-many relationship is typically represented with a crow's foot notation.
Correct Answer:
B
— With a crow's foot notation
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Q. In an ER model, what does a solid line between two entities indicate?
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A.
A weak relationship
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B.
A strong relationship
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C.
A one-to-many relationship
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D.
A many-to-many relationship
Solution
A solid line between two entities indicates a strong relationship in an ER model.
Correct Answer:
B
— A strong relationship
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Q. In an ER model, what does a solid line connecting two entities represent?
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A.
A weak relationship
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B.
A strong relationship
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C.
An attribute
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D.
A foreign key constraint
Solution
A solid line connecting two entities in an ER model represents a strong relationship.
Correct Answer:
B
— A strong relationship
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Q. What does the term 'cardinality' refer to in an ER model?
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A.
The number of attributes in an entity
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B.
The number of entities in a relationship
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C.
The type of data stored in an entity
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D.
The uniqueness of an entity
Solution
Cardinality refers to the number of entities involved in a relationship.
Correct Answer:
B
— The number of entities in a relationship
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Q. What is a business rule in the context of an ER model?
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A.
A guideline for database performance
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B.
A constraint that defines how data can be created, stored, and modified
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C.
A method for indexing data
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D.
A type of transaction control
Solution
A business rule defines constraints on how data can be created, stored, and modified in a database.
Correct Answer:
B
— A constraint that defines how data can be created, stored, and modified
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Q. What is a weak entity in an ER model?
-
A.
An entity that cannot exist without a strong entity
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B.
An entity with no attributes
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C.
An entity that has a composite key
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D.
An entity that is not related to any other entity
Solution
A weak entity is one that cannot exist without a strong entity.
Correct Answer:
A
— An entity that cannot exist without a strong entity
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Q. What is the main goal of creating an ER model?
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A.
To define the physical structure of the database
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B.
To visualize the data requirements and relationships
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C.
To write SQL queries
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D.
To implement security measures
Solution
The main goal of creating an ER model is to visualize the data requirements and relationships.
Correct Answer:
B
— To visualize the data requirements and relationships
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Q. What is the main goal of using an ER model in database design?
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A.
To create complex SQL queries
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B.
To visually represent data and relationships
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C.
To enforce data integrity
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D.
To optimize database performance
Solution
The main goal of using an ER model is to visually represent data and the relationships between them.
Correct Answer:
B
— To visually represent data and relationships
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Q. What is the primary key in an entity?
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A.
A unique identifier for each record
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B.
An attribute that can be null
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C.
A foreign key from another entity
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D.
An attribute that is not used in relationships
Solution
The primary key is a unique identifier for each record in an entity.
Correct Answer:
A
— A unique identifier for each record
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Q. What is the purpose of a foreign key in a database?
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A.
To uniquely identify a record
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B.
To establish a link between two tables
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C.
To enforce data integrity
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D.
To improve query performance
Solution
A foreign key is used to establish a link between two tables in a database.
Correct Answer:
B
— To establish a link between two tables
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Q. What is the role of an attribute in an ER model?
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A.
To represent a relationship
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B.
To define the properties of an entity
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C.
To serve as a primary key
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D.
To enforce data integrity
Solution
An attribute defines the properties or characteristics of an entity in an ER model.
Correct Answer:
B
— To define the properties of an entity
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Q. Which of the following best describes a business rule?
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A.
A guideline for database design
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B.
A constraint on data values
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C.
A policy that governs data usage
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D.
All of the above
Solution
A business rule can be a guideline, a constraint, or a policy regarding data.
Correct Answer:
D
— All of the above
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Q. Which of the following best describes a primary key?
-
A.
A unique identifier for a record in a table
-
B.
A foreign key that links to another table
-
C.
An attribute that can have null values
-
D.
A composite of multiple attributes
Solution
A primary key is a unique identifier for a record in a table.
Correct Answer:
A
— A unique identifier for a record in a table
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Q. Which of the following is a characteristic of a strong entity?
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A.
It has a partial key
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B.
It can exist independently
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C.
It is represented by a dashed rectangle
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D.
It has no attributes
Solution
A strong entity can exist independently and has its own primary key.
Correct Answer:
B
— It can exist independently
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Q. Which of the following is an example of an attribute in an ER model?
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A.
Customer
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B.
Orders
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C.
OrderID
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D.
Many-to-Many
Solution
OrderID is an example of an attribute in an ER model.
Correct Answer:
C
— OrderID
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