text: CREATE TABLE users(	
  	first_name VARCHAR(50) NOT NULL,
  	last_name VARCHAR(50) NOT NULL,
  	roll_no CHAR(7) NOT NULL UNIQUE,
  	username VARCHAR(50) NOT NULL PRIMARY KEY,
  	password VARCHAR(200) NOT NULL,
  	email VARCHAR(50) NOT NULL UNIQUE);
  
  CREATE TABLE department(
  	d_id VARCHAR(10) NOT NULL PRIMARY KEY,
  	d_name VARCHAR(200) NOT NULL);
  
  CREATE TABLE post(
  	p_id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  	url VARCHAR(512) NOT NULL UNIQUE,
  	title TEXT NOT NULL,
  	description LONGTEXT,
  	thumb TEXT NOT NULL,
  	counter BIGINT NOT NULL,
  	PRIMARY KEY(p_id));
  
  CREATE TABLE bookmark(
  	read_status BIT NOT NULL,
  	time_added datetime NOT NULL);
  
  
  ALTER TABLE users ADD d_id VARCHAR(10) NOT NULL;
  ALTER TABLE users ADD FOREIGN KEY ('d_id') REFERENCES department('d_id');
  
  ALTER TABLE bookmark ADD username VARCHAR(50) NOT NULL;
  ALTER TABLE bookmark ADD p_id BIGINT UNSIGNED NOT NULL;
  ALTER TABLE bookmark ADD b_id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY;
  ALTER TABLE users ADD FOREIGN KEY ('username') REFERENCES users('username');
  ALTER TABLE users ADD FOREIGN KEY ('p_id') REFERENCES post('p_id');
  
  INSERT INTO department
  			(
  				d_id,
  				d_name
  			)
  			VALUES
  			('CO','Computer Science & Engineering'),
  			('EC','Electronics & Communication Engineering'),
  			('EE','Electrical & Electronics Engineering'),
  			('ME','Mechanical Engineering'),
  			('CH','Chemical Engineering'),
  			('MN','Mining Engineering'),
  			('MT','Metallurgical Engineering'),
  			('IT','Information Technology'),
  			('CV','Civil Engineering');
  