Assignment: Object Based Databases | Database Management System (DBMS) - Software Development PDF Download

Multiple Choice Questions (MCQs)

Q.1. Which of the following statements is true about object-based databases?
(a) They store data in tables with predefined schema
(b) They use a hierarchical data model
(c) They support complex data types and inheritance
(d) They cannot handle large volumes of data

Ans. (c)

Q.2. Which of the following is an advantage of using object-based databases?
(a) Improved query performance
(b) Limited support for complex data types
(c) Inflexible schema definition
(d) Poor scalability for large datasets

Ans. (a)

Q.3. In an object-based database, an object is defined as:
(a) A tuple with fixed attributes
(b) A collection of related records
(c) An instance of a class with attributes and methods
(d) A single value representing a data item

Ans. (c)

Q.4. Which of the following is an example of a complex data type in object-based databases?
(a) Integer
(b) String
(c) Array
(d) Boolean

Ans. (c)

Q.5. Which of the following is a limitation of object-based databases?
(a) Limited support for complex data types
(b) Inability to handle large volumes of data
(c) Difficulty in querying and retrieving data
(d) Inflexible schema definition

Ans. (d)

Higher Order Thinking Questions (HOTS)

Q.1. Explain the concept of inheritance in object-based databases and its significance.

Inheritance in object-based databases refers to the ability of one object to inherit properties and behavior from another object. It allows for the creation of hierarchical relationships between objects, where a subclass (derived class) inherits attributes and methods from a superclass (base class). Inheritance facilitates code reuse, reduces redundancy, and enhances modularity. It enables the creation of object hierarchies that represent real-world relationships, promoting data organization and management efficiency.

Q.2. Discuss the advantages and disadvantages of using object-based databases compared to relational databases.

Advantages of object-based databases compared to relational databases:

• Support for complex data types: Object-based databases can handle complex data types such as arrays, structures, and user-defined types, providing more flexibility for modeling real-world entities.
• Improved query performance: With their ability to represent complex relationships and hierarchical structures, object-based databases can offer improved query performance, especially for complex queries involving multiple objects.
• Flexible schema: Object-based databases allow for a more flexible schema definition, as objects can evolve over time without the need for altering a predefined table structure.
• Better support for object-oriented programming: Object-based databases align well with object-oriented programming paradigms, facilitating seamless integration between application code and database objects.

Disadvantages of object-based databases compared to relational databases:

• Complexity: Object-based databases can be more complex to design and manage due to the additional considerations for object modeling, inheritance, and complex data types.
• Limited industry adoption: Relational databases have been widely adopted and are supported by many database management systems, while object-based databases have seen more limited industry adoption.
• Difficulty in data migration: Converting existing relational data to object-based databases can be challenging, requiring careful consideration and data migration strategies.
• Querying and reporting challenges: Object-based databases may have limitations in terms of querying and reporting capabilities, as they often require specific query languages and tools.

Q.3. How does an object-based database handle complex data types? Provide examples to illustrate your answer.

Object-based databases provide support for complex data types, allowing for the storage and manipulation of structured data. Examples of complex data types include arrays, structures, sets, and user-defined types. For instance, an object in an object-based database can have an attribute that stores an array of values, such as an array of integers or an array of strings. This capability enables the representation of more intricate data structures and relationships, supporting richer data modeling and enhanced data management.

Q.4. Describe the process of querying and retrieving data from an object-based database.

Querying and retrieving data from an object-based database typically involves writing queries in the query language supported by the database management system. The query language allows users to specify the criteria for selection, projection (choosing specific attributes), and joining objects based on their relationships. The process can be similar to querying in relational databases, but with additional features and syntax tailored to object-oriented concepts. The query language may support operations like object navigation, filtering based on attributes or methods, and retrieval of related objects through associations or inheritance hierarchies.

Q.5. Explain the concept of encapsulation in object-based databases and its role in data management.

Encapsulation in object-based databases refers to the principle of combining data and the operations (methods) that manipulate the data into a single entity, known as an object. Encapsulation ensures that the internal state of an object is protected and can only be accessed through defined methods. It promotes data integrity and encapsulates the logic and behavior associated with the data, preventing unauthorized modifications or access. Encapsulation is a fundamental concept in object-oriented programming and plays a crucial role in data management, providing encapsulated objects that can be stored, queried, and manipulated within the object-based database.

Fill in the Blanks

1. In object-based databases, an object represents a _______ with _______ and _______.

In object-based databases, an object represents a real-world entity with attributes and methods.

2. _______ is a feature of object-based databases that allows one object to inherit properties and behavior from another.

Inheritance is a feature of object-based databases that allows one object to inherit properties and behavior from another.

3. Object-based databases offer support for _______ data types, such as _______ and _______.

Object-based databases offer support for complex data types, such as arrays and structures.

4. The process of retrieving data from an object-based database involves writing _______ to specify the criteria for selection.

The process of retrieving data from an object-based database involves writing queries to specify the criteria for selection.

5. _______ is a principle in object-based databases that combines data and the operations that manipulate the data into a single entity.

Encapsulation is a principle in object-based databases that combines data and the operations that manipulate the data into a single entity.

True or False

1. Object-based databases use a fixed schema to store data. (True/False)

Ans. False

2. Object-based databases offer better scalability for large datasets compared to relational databases. (True/False)

Ans. False

3. Complex data types cannot be stored in object-based databases. (True/False)

Ans. False

4. Querying and retrieving data from an object-based database is a straightforward process. (True/False)

Ans. False

5. Encapsulation is a fundamental concept in object-based databases. (True/False)

Ans. True

Hands-On Questions

Q.1. Consider the following object definition in an object-based database:

class Employee {
    int employeeId;
    String name;
    double salary;
}

Create an instance of the 'Employee' class and assign the following values:

• 'employeeId': 12345
• 'name': "John Smith"
• 'salary': 5000.0

Employee employee = new Employee();

employee.employeeId = 12345;

employee.name = "John Smith";

employee.salary = 5000.0;

Q.2. Suppose you have an object-based database that stores information about books. Define a class 'Book' with the following attributes:

• title: string
• author: string
• year: integer
• price: float

Create two instances of the 'Book' class with the following information:

• Book 1:
  • Title: "The Great Gatsby"
  • Author: "F. Scott Fitzgerald"
  • Year: 1925
  • Price: 10.99
• Book 2:
  • Title: "To Kill a Mockingbird"
  • Author: "Harper Lee"
  • Year: 1960
  • Price: 12.99

class Book {

    String title;

    String author;

    int year;

    float price;

}

Book book1 = new Book();

book1.title = "The Great Gatsby";

book1.author = "F. Scott Fitzgerald";

book1.year = 1925;

book1.price = 10.99;

Book book2 = new Book();

book2.title = "To Kill a Mockingbird";

book2.author = "Harper Lee";

book2.year = 1960;

book2.price = 12.99;

Q.3. Write a SQL query to retrieve all the books from the object-based database that were published after the year 2000.

SQL query to retrieve books published after the year 2000:

SELECT * FROM books WHERE year > 2000;

Q.4. Explain the steps involved in creating a new object in an object-based database and storing it.

The steps involved in creating a new object in an object-based database and storing it typically include:

• Defining the object's class, including its attributes and methods.
• Instantiating a new object of the defined class.
• Assigning values to the object's attributes.
• Saving the object to the object-based database using appropriate storage or persistence mechanisms.

Q.5. Discuss the process of modifying an existing object in an object-based database, including any considerations or precautions to be taken.

Modifying an existing object in an object-based database involves the following steps:

• Retrieving the object from the database using appropriate query or retrieval mechanisms.
• Making the necessary modifications to the object's attributes.
• Saving the modified object back to the database, ensuring any associated changes are properly propagated and persisted. Considerations include handling data integrity, concurrency, and transaction management to ensure consistency and avoid data corruption.