MCQs

What is a DbContext in Entity Framework?

a. An object that represents a database connection
b. A base class for all model classes in Entity Framework
c. An object that manages the entity objects and the underlying database connection
d. A class that represents a database table

Answer: c. An object that manages the entity objects and the underlying database connection

Explanation: DbContext is an object that manages the entity objects and the underlying database connection in Entity Framework. It is responsible for tracking changes to the entity objects and persisting these changes to the database.

Which approach in Entity Framework allows developers to generate database schema from the model classes?

a. Code First
b. Model First
c. Database First
d. None of the above

Answer: a. Code First

Explanation: The Code First approach in Entity Framework allows developers to generate database schema from the model classes. With Code First, developers can define the database schema using C# or VB.NET code, and Entity Framework will create the database schema based on the code.

Which type of volume gateway stores the entire copy of data locally and backup the data to AWS?

1. Cached gateway
2. Stored volumes

Answer: B) Stored volumes

Explanation:

Stored volumes store the entire copy of data locally and backup the data to AWS.

What is the Availability zone in AWS?

1. An Availability zone is a geographical area or collection of data centers.
2. An Availability zone is an isolated logical data center in a region
3. An Availability zone is the end-points for AWS.

Answer: B) An Availability zone is an isolated logical data center in a region

Explanation:

An Availability zone is an isolated logical data center in a region, these are multiplied within each region.

Which of the following is TRUE about TCL?

1. Transactions can be saved to the database and rolled back with the help of TCL commands in SQL.
2. There will be certain privileges that each user has; consequently, the data can be accessed by them using TCL.
3. Our data is stored in a table that is described by the schema, thus TCL commands deal with the schema.
4. SQL TCL commands can be used to perform any kind of retrieval or manipulation of the data present in SQL tables.

Answer: A) Transactions can be saved to the database and rolled back with the help of TCL commands in SQL

Explanation:

Transactions can be saved to the database and rolled back with the help of TCL commands in SQL.

Difference between GRAND & REVOKE command is/are?

1. The GRANT command can be used to grant a user access to databases and tables whereas The REVOKE command can be used to revoke all access privileges already assigned to the user.
2. The REVOKE command can be used to grant a user access to databases and tables whereas The GRANT command can be used to revoke all access privileges already assigned to the user.
3. A transaction can be rolled back to its last saved state.
4. None of the above

Answer: A) The GRANT command can be used to grant a user access to databases and tables whereas The REVOKE command can be used to revoke all access privileges already assigned to the user

Explanation:

The GRANT command can be used to grant a user access to databases and tables whereas The REVOKE command can be used to revoke all access privileges already assigned to the user.

What is TRUE about PL/SQL functionalities?

1. Conditions and loops are fundamental elements of procedural languages like PL/SQL.
2. Various types and variables can be declared, as can procedures and functions, as well as types and variables of those types.
3. Arrays can be used with it as well as handling exceptions (runtime errors).
4. All of the above

Answer: D) All of the above

Explanation:

TRUE about PL/SQL functionalities –

1. Conditions and loops are fundamental elements of procedural languages like PL/SQL.
2. Various types and variables can be declared, as can procedures and functions, as well as types and variables of those types.
3. Arrays can be used with it as well as handling exceptions (runtime errors).

Which is the base class of the String() Constructor?

1. String
2. System.IO.String
3. System.Strings
4. System.String

Answer: D) System.String

Explanation:

In C#, System.String is a base class for all String related methods, properties, constructors, and operators.

What is the difference between session object and application object in ASP.Net?

1. The session object is used to maintain the session of each user while an application object is created while a user enters in the application
2. Session objects are created on the server while application objects are created on the client side.
3. Session objects are used to handle database communication while application objects are used to handle communication between two different domains.
4. All of the above

Answer: A) The session object is used to maintain the session of each user while an application object is created while a user enters in the application

Explanation:

The difference between a session object and an application object in ASP.Net is that: Session object is used to maintain the session of each user while an application object is created while a user enters the application.

What is the difference between Debug and Trace class in ASP.Net?

1. The Debug class is used to debug both builds and releases while the Trace class is used to debug the builds only
2. Debug class is used in ASP core while Trace is used in ASP MCC
3. The Debug class is used to debug the builds while the Trace class is used to debug both builds and releases
4. All of the above

Answer: C) The Debug class is used to debug the builds while the Trace class is used to debug both builds and releases

Explanation:

The difference between Debug and Trace class in ASP.Net is - The Debug class is used to debug the builds while the Trace class is used to debug both builds and releases.

What is String in C# meant for?

1. A variable
2. A Class
3. An Array
4. An object

Answer: D) An object

Explanation:

In C#, String is an object of System.String class.

Consider a RESTful API that represents a social media platform, and the following code snippets.

 

const requestLogger = (req, res, next) => {
  console.log(`${req.method} ${req.path} - ${req.ip}`);
  next();
};

const authenticateUser = (req, res, next) => {
  const authToken = req.headers.authorization?.split(' ')[1];
  if (authToken) {
    // Authenticate the user using the auth token
    req.user = { id: 1234, username: 'johndoe' };
    next();
  } else {
    res.status(401).send('Unauthorized');
  }
};

const validatePostData = (req, res, next) => {
  const { text, mediaUrl } = req.body;
  if (text && mediaUrl) {
    next();
  } else {
    res.status(400).send('Invalid request data');
  }
};

const rateLimiter = (req, res, next) => {
  // Rate limit the request based on the client's IP address
  const ipAddress = req.ip;
  // ...
  next();
};

POST /api/posts HTTP/1.1
Content-Type: application/json

{
  "text": "Hello, world!",
  "mediaUrl": "https://example.com/image.jpg"
}

 

Which of the following code snippets illustrates the use of middleware in this API?

const app = express();
app.use(requestLogger);
app.use(authenticateUser);
app.use(validatePostData);
app.use(rateLimiter);
 

app.post('/api/posts', (req, res) => {
  const { text, mediaUrl } = req.body;
  // ...
});
 

app.post('/api/posts', validatePostData, (req, res) => {
  const { text, mediaUrl } = req.body;
  // ...
});
 

app.post('/api/posts', rateLimiter, (req, res) => {
  const { text, mediaUrl } = req.body;
  // ...
});
 

Consider the following RESTful API endpoint and response.

 

GET /api/books?sort=desc&limit=10&offset=20 HTTP/1.1
Accept: application/json

{
  "count": 100,
  "next": "/api/books?sort=desc&limit=10&offset=30",
  "previous": "/api/books?sort=desc&limit=10&offset=10",
  "results": [
    {
      "id": 1,
      "title": "To Kill a Mockingbird",
      "author": "Harper Lee",
      "publication_date": "1960-07-11",
      "genre": "Novel"
    },
    {
      "id": 2,
      "title": "1984",
      "author": "George Orwell",
      "publication_date": "1949-06-08",
      "genre": "Dystopian Fiction"
    },
    {
      "id": 3,
      "title": "Brave New World",
      "author": "Aldous Huxley",
      "publication_date": "1932-06-11",
      "genre": "Dystopian Fiction"
    }
  ]
}

 

Which of the following statements is true about the endpoint and response?

The endpoint is using a custom HTTP method. The response is paginated and sorted by the publication_date field in ascending order.

The endpoint is using a standard HTTP method. The response is paginated and sorted by the title field in descending order.

The endpoint is using a standard HTTP method. The response is paginated and sorted by the publication_date field in descending order.

The endpoint is using a custom HTTP method. The response is paginated and sorted by the title field in ascending order.

Consider a RESTful API that represents user accounts and the following code snippets.

 

# Code Snippet 1
GET /oauth/authorize?response_type=code&client_id=1234&redirect_uri=https://example.com/callback HTTP/1.1
Host: authorization-server.example.com

# Code Snippet 2
POST /oauth/token HTTP/1.1
Host: authorization-server.example.com
Content-Type: application/x-www-form-urlencoded

grant_type=authorization_code&code=AUTHORIZATION_CODE&redirect_uri=https://example.com/callback&client_id=1234&client_secret=abcdef

 

Which of the following statements is true about OAuth and the code snippets?

The first code snippet requests an access token using the OAuth 2.0 authorization code flow. The second code snippet exchanges the authorization code for an access token using a POST request to the authorization server's /oauth/token endpoint.

The first code snippet requests an authorization code using the OAuth 2.0 implicit flow, and the second code snippet exchanges the authorization code for a refresh token using a POST request to the authorization server's /oauth/token endpoint.

The first code snippet requests an access token using the OAuth 1.0a flow, and the second code snippet exchanges the access token for a request token using a POST request to the authorization server's /oauth/request_token endpoint.

The first code snippet requests an authorization code using the OAuth 2.0 client credentials flow, and the second code snippet exchanges the authorization code for an access token using a POST request to the authorization server's /oauth/access_token endpoint.

Choose the expression that deletes a column.

DELETE status FROM queue

ALTER TABLE queue DROP COLUMN status

DELETE COLUMN status FROM queue

ALTER TABLE queue DROP status COLUMN

Choose the expressions that are not correct.

SELECT * FROM categories WHERE id <> NULL

SELECT * FROM categories WHERE id != NULL

SELECT * FROM categories WHERE id IS NULL

SELECT * FROM categories WHERE id IS NOT NULL

Consider a RESTful API that represents a job application service and the following code snippets.

 

# Code Snippet 1
POST /api/job_applications HTTP/1.1 Content-Type: application/json { "job_title": "Software Engineer", "company_name": "HackerRank Inc.", "date_applied": "2023-02-18", "status": "Pending" }

# Code Snippet 2
GET /api/job_applications HTTP/1.1

# Code Snippet 3
GET /api/job_applications/123 HTTP/1.1

# Code Snippet 4
PUT /api/job_applications/123 HTTP/1.1 Content-Type: application/json { "status": "Interview Scheduled" }

Which of the following statements are true about HTTP methods and the code snippets?

The first code snippet gets a list of job applications using the GET method, and the second code snippet creates a new job application using the POST method.

The first code snippet creates a new job application using the POST method, and the second code snippet gets a list of job applications using the GET method.

The third code snippet updates a specific job application using the PATCH method, and the fourth code snippet deletes a job application using the GET method.

The third code snippet gets a specific job application using the GET method, and the fourth code snippet updates a specific job application using the PUT method.

Select an expression that demonstrates a self join type.

SELECT * FROM users users, users clients

SELECT * FROM users SELF JOIN users AS clients

SELECT * FROM users JOIN users AS clients

None of the above, a self join type does not exist in MySQL

Select the expression that causes a MySQL error.

SELECT AVG( id ) FROM categories

SELECT AVG( id ) FROM categories GROUP BY type

SELECT 'average', AVG( id ) FROM categories GROUP BY 1

None of the above, all expressions are correct

Asp.net has a file named web.config

To store global information and variable definitions

To configure the domain server

To configure to domain client

Store information about web browser

Which of the following is not an ASP.NET event?

Init

Import

Load

All

Which protocol is used to call a web service?

SOAP Protocol

HTTP Protocol

TCP Protocol

FTP Protocol

Consider a RESTful API that uses token-based authentication and the following code snippets.

 

# Example 1: User login
import bcrypt

def verify_password(plain_password, hashed_password):
    return bcrypt.checkpw(plain_password.encode('utf-8'), hashed_password.encode('utf-8'))

def login(username, password):
    user = get_user_by_username(username)
    if user and verify_password(password, user['password']):
        return generate_token(user['id'])

def generate_token(user_id):
    payload = {'sub': user_id, 'exp': datetime.utcnow() + timedelta(hours=2)}
    return jwt.encode(payload, SECRET_KEY, algorithm='HS256')

# Example 2: API endpoint
import jwt

def authenticate(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        try:
            auth_header = request.headers.get('Authorization')
            token = auth_header.split()[1]
            payload = jwt.decode(token, SECRET_KEY, algorithms=['HS256'])
            g.user_id = payload['sub']
            return func(*args, **kwargs)
        except jwt.ExpiredSignatureError:
            abort(401, 'Token has expired')
        except jwt.InvalidTokenError:
            abort(401, 'Invalid token')
    return wrapper

@app.route('/books')
@authenticate
def get_books():
    user_id = g.user_id
    books = get_books_by_user_id(user_id)
    return jsonify({'books': books})

Which of the following statements is true about authentication and the code snippets?
The first code snippet uses a salted SHA-256 hash to store user passwords, and the second code snippet authenticates users by checking their passwords against the hash.
The first code snippet generates a JWT with an expiration time of 2 hours, and the second code snippet authenticates API endpoints by verifying the JWT included in the Authorization header.
The first code snippet retrieves the user's password from the database and compares it directly to the plaintext password provided during login, and the second code snippet authenticates API endpoints by checking the user's username and password against the database.
The first code snippet generates a random API key for each user, and the second code snippet authenticates API endpoints by checking the API key included in the Authorization header.