Database codes

DATABASE

-- Create a new database CREATE DATABASE IF NOT EXISTS mydatabase; USE mydatabase; -- Create a table CREATE TABLE IF NOT EXISTS users ( id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(50) NOT NULL, email VARCHAR(50) NOT NULL ); -- Insert data into the table INSERT INTO users (name, email) VALUES ('John Doe', 'john@example.com'), ('Jane Smith', 'jane@example.com'), ('Mike Johnson', 'mike@example.com'); -- Query the data SELECT * FROM users; -- Update data in the table UPDATE users SET email = 'john.doe@example.com' WHERE id = 1; -- Delete data from the table DELETE FROM users WHERE id = 3; -- Add a new column to the table ALTER TABLE users ADD COLUMN phone VARCHAR(20); -- Update data in the table to include phone numbers UPDATE users SET phone = '+1234567890' WHERE id IN (1, 2); -- Query the updated data SELECT * FROM users;

This covers the following operations:

1. It creates a database called "mydatabase" (if it doesn't exist) and sets it as the current database.
2. It creates a table named "users" with three columns: "id" (an auto-incremented primary key), "name" (a non-null VARCHAR column), and "email" (a non-null VARCHAR column).
3. It inserts three rows of data into the "users" table, providing values for the "name" and "email" columns.
4. It queries the data from the "users" table and displays the results.
5. It updates the email of the user with id 1 to 'john.doe@example.com' using the UPDATE statement.
6. It deletes the user with id 3 from the table using the DELETE statement.
7. It adds a new column named "phone" of type VARCHAR(20) to the "users" table using the ALTER TABLE statement.
8. It updates the data in the table to include phone numbers for the users with id 1 and 2.
9. Finally, it queries the updated data from the "users" table and displays the results.