SQL: Structured Query Language

SQL (Structured Query Language) is a programming language designed for managing and manipulating data in relational databases. It provides a standardized way to interact with the database, allowing users to create, retrieve, update, and delete data.

Learning SQL is essential for anyone working with databases, as it is the primary language used to communicate with relational database management systems (RDBMS). SQL syntax is easy to read and write, making it accessible to both beginners and experienced developers.

Let's take a look at a simple example of using SQL to create a table and insert data into it.

1if __name__ == '__main__':
2  # Python logic here
3  import sqlite3
4
5  # Create a connection to the SQLite database
6  conn = sqlite3.connect('mydatabase.db')
7
8  # Create a cursor object to execute SQL queries
9  cursor = conn.cursor()
10
11  # Create a table
12  cursor.execute('''
13    CREATE TABLE IF NOT EXISTS employees (
14      id INTEGER PRIMARY KEY,
15      name TEXT NOT NULL,
16      age INTEGER,
17      salary REAL
18    )
19  ''')
20
21  # Insert data into the table
22  employees = [
23    (1, 'John Smith', 30, 50000.00),
24    (2, 'Jane Doe', 25, 45000.00),
25    (3, 'Mark Johnson', 35, 60000.00)
26  ]
27
28  cursor.executemany('INSERT INTO employees VALUES (?, ?, ?, ?)', employees)
29
30  # Commit the changes
31  conn.commit()
32
33  # Close the connection
34  conn.close()
35
36  print('Database created and data inserted successfully!')

In this example, we are using SQL and Python to create a new table called 'employees' with columns for 'id', 'name', 'age', and 'salary'. We then insert three records into the table. Finally, we commit the changes and close the database connection.

With SQL, you can perform various operations on the database, such as querying data, updating records, and deleting data. It provides a powerful and flexible way to manage and manipulate the data stored in relational databases.

xxxxxxxxxx

  print('Database created and data inserted successfully!')

if __name__ == '__main__':

  # Python logic here

  import sqlite3

​

  # Create a connection to the SQLite database

  conn = sqlite3.connect('mydatabase.db')

​

  # Create a cursor object to execute SQL queries

  cursor = conn.cursor()

​

  # Create a table

  cursor.execute('''

    CREATE TABLE IF NOT EXISTS employees (

      id INTEGER PRIMARY KEY,

      name TEXT NOT NULL,

      age INTEGER,

      salary REAL

    )

  ''')

​

  # Insert data into the table

  employees = [

    (1, 'John Smith', 30, 50000.00),

    (2, 'Jane Doe', 25, 45000.00),

    (3, 'Mark Johnson', 35, 60000.00)

  ]

​

  cursor.executemany('INSERT INTO employees VALUES (?, ?, ?, ?)', employees)

​