What is the main purpose of a data model?
a) To represent the structure of a database
b) To store data in a file
c) To generate reports
d) To manage network resources
Which of the following is not a type of data model?
a) Hierarchical model
b) Network model
c) Relational model
d) Physical model
Which data model uses tables to store data and relationships?
a) Network model
b) Relational model
c) Object-oriented model
d) Hierarchical model
What is the main advantage of using a relational data model?
a) Easy to manage large volumes of data
b) Easy to understand and use
c) Supports complex data types
d) Allows for real-time data processing
Which of the following is a key concept in the entity-relationship (ER) model?
a) Relationships
b) Keys
c) Attributes
d) All of the above
What does the term “normalization” refer to in database design?
a) Organizing data to reduce redundancy
b) Improving data retrieval speed
c) Adding more indexes to tables
d) Enhancing the security of the database
What is the highest normal form of a database?
a) First normal form (1NF)
b) Second normal form (2NF)
c) Third normal form (3NF)
d) Boyce-Codd normal form (BCNF)
Which of the following is true about a primary key in a relational database?
a) It can have duplicate values
b) It uniquely identifies a record in a table
c) It can be null
d) It is not necessary for each table
Which of the following relationships is represented by a many-to-many (M:N) relationship in an ER diagram?
a) One student can enroll in multiple courses, and each course can have multiple students
b) One student can enroll in multiple courses, but each course has only one student
c) One course can have multiple students, but each student enrolls in only one course
d) One teacher can teach multiple students
Which of the following is an example of a foreign key in a database?
a) The unique identifier of a record in the current table
b) A reference to a primary key in another table
c) An index to speed up queries
d) A field that stores the date and time of record creation
What does “referential integrity” ensure in a relational database?
a) That the data is accurate and consistent
b) That data in one table matches data in another table
c) That the data is normalized
d) That all tables have a primary key
Which of the following is used to design the physical structure of a database?
a) Data model
b) Entity-relationship diagram
c) Database schema
d) Table design
What is an index in a relational database?
a) A field used for storing unique values
b) A mechanism for quickly locating data
c) A table that stores metadata about the database
d) A tool for ensuring data consistency
Which of the following best describes a “many-to-one” relationship?
a) One entity is related to multiple entities
b) Multiple entities are related to one entity
c) One entity has a direct relationship with another entity
d) No relationship exists between entities
In a database, what does the term “cardinality” refer to?
a) The maximum number of rows in a table
b) The type of relationship between two entities
c) The number of attributes in a table
d) The process of converting data into a relational model
Which of the following is a disadvantage of using a hierarchical data model?
a) Data is easy to retrieve
b) The structure is flexible and easy to modify
c) It is difficult to represent many-to-many relationships
d) Data can be represented as a set of independent objects
What is the purpose of a “junction table” in a many-to-many relationship?
a) To store the data in a foreign key
b) To store records that connect two tables
c) To store the primary key of each entity
d) To store records in a hierarchical structure
Which of the following types of constraints ensures that a column’s value is unique across the entire table?
a) NOT NULL
b) UNIQUE
c) FOREIGN KEY
d) CHECK
Which of the following is a common database design approach?
a) Bottom-up approach
b) Top-down approach
c) Both A and B
d) None of the above
Which of the following statements is true regarding denormalization?
a) It involves combining tables to eliminate redundancy
b) It increases the normalization level of a database
c) It simplifies query writing by reducing table joins
d) It always improves performance
What does “data integrity” refer to in the context of database design?
a) The process of creating secure data backups
b) Ensuring that data remains accurate and consistent over its lifecycle
c) The ability to retrieve data quickly
d) The process of organizing data into tables
Which of the following is not part of an ER diagram?
a) Entity
b) Attribute
c) Relationship
d) Index
What does “atomicity” in the context of database transactions ensure?
a) Data is normalized
b) A transaction is either fully completed or not executed at all
c) Data can be backed up
d) The database has no duplicates
Which SQL command is used to create a new table in a relational database?
a) INSERT
b) CREATE
c) ALTER
d) DROP
Which of the following is not a step in the database design process?
a) Gathering requirements
b) Creating an ER diagram
c) Defining a relational schema
d) Writing SQL queries
Which type of relationship in a database uses a third table to link two other tables together?
a) One-to-one
b) One-to-many
c) Many-to-many
d) Many-to-one
What is a “composite key” in a database?
a) A key formed by combining multiple foreign keys
b) A key formed by combining multiple attributes to create a unique identifier
c) A unique identifier for each table
d) A key that connects multiple tables together
Which of the following is a disadvantage of the relational data model?
a) Flexibility in handling complex relationships
b) Requires predefined schema
c) Easy to perform complex queries
d) Reduces redundancy
