Instructions: Read each question carefully and choose the best answer from the options provided.
1. Which of the following is NOT a benefit of using a database management system (DBMS)?
(a) Data integrity
(b) Data security
(c) Improved performance
(d) Increased data redundancy
2. The data model that represents data in the form of objects and their relationships is known as:
(a) Hierarchical model
(b) Network model
(c) Relational model
(d) Object-oriented model
3. Which of the following is a type of database schema?
(a) Physical schema
(b) Logical schema
(c) External schema
(d) All of the above
4. The Structured Query Language (SQL) is used for:
(a) Defining and manipulating data in a database
(b) Creating and modifying database structures
(c) Managing user access to the database
(d) All of the above
5. The following SQL statement is used to create a table:
(a) CREATE TABLE
(b) ALTER TABLE
(c) DROP TABLE
(d) INSERT INTO
6. The operator that combines multiple conditions in an SQL query is:
(a) AND
(b) OR
(c) NOT
(d) XOR
7. Which of the following is NOT a type of database query?
(a) Select query
(b) Update query
(c) Delete query
(d) Insert query
8. The cardinality of a relationship between two entities specifies:
(a) The number of entities in each entity set
(b) The number of relationships between the two entities
(c) The type of relationship between the two entities
(d) None of the above
9. The process of normalizing a database involves:
(a) Removing redundant data
(b) Enforcing data integrity
(c) Optimizing database performance
(d) All of the above
10. The Boyce-Codd Normal Form (BCNF) is a type of normal form that:
(a) Eliminates transitive dependencies
(b) Eliminates partial dependencies
(c) Eliminates multivalued dependencies
(d) Eliminates all types of dependencies
Answer Key:
- d
- d
- d
- d
- a
- a
- d
- a
- d
- a
Additional Practice Questions
11. Explain the difference between a primary key and a foreign key.
12. Describe the three levels of abstraction in a database schema.
13. Write an SQL query to retrieve all customers with orders over $100.
14. Normalize the following relation:
Customer(customer_id, customer_name, customer_address, customer_order)
15. Discuss the advantages and disadvantages of using a hierarchical data model.
Answers:
11. Difference between Primary Key and Foreign Key:
- Primary key: A unique identifier for each record in a table.
- Foreign key: A column in a table that references the primary key of another table.
12. Three Levels of Abstraction in a Database Schema:
- Physical schema: Describes the physical storage of data (e.g., data types, file organization).
- Logical schema: Describes the data structures and relationships (e.g., tables, columns, keys).
- External schema: Describes the user’s view of the data (e.g., user-defined tables, views).
13. SQL Query to Retrieve Customers with Orders Over $100:
SELECT *
FROM Customer
WHERE customer_order > 100;
14. Normalized Relation:
Customer(customer_id, customer_name, customer_address)
Order(order_id, customer_id, order_date, order_amount)
15. Advantages and Disadvantages of Hierarchical Data Model:
Advantages:
- Simple and easy to understand
- Efficient for tree-structured data
- Maintains hierarchical relationships
Disadvantages:
- Difficult to handle complex relationships
- Data redundancy and inconsistency
- Limited flexibility and scalability
