Inserting Data

Now that you have a table, it’s time to store real data in it.

This is where your database becomes useful.

What You Will Do

You will:

• Insert a user into the database
• Save the data
• Confirm it was added

Step 1: Update database.py

Replace your code with this:

import sqlite3

conn = sqlite3.connect("database.db")
cursor = conn.cursor()

# insert data
cursor.execute("INSERT INTO users (name) VALUES (?)", ("John",))

conn.commit()
conn.close()

print("User inserted successfully")

Step 2: Run the File

python database.py

What Just Happened?

• A new row was added to the users table
• The name “John” was stored
• The database now contains data

Important Concept

Why Use ?

cursor.execute("INSERT INTO users (name) VALUES (?)", ("John",))

• The ? is a placeholder
• It safely inserts data into the query
• Prevents errors and security issues

Step 3: Insert Multiple Users

Try adding more:

cursor.execute("INSERT INTO users (name) VALUES (?)", ("Alice",))
cursor.execute("INSERT INTO users (name) VALUES (?)", ("Bob",))

Run the file again.

Now your database has multiple users.

Why This Matters

You are now:

• Storing real data
• Building persistent applications
• Moving from temporary → permanent data

Common Mistakes

• ❌ Forgetting conn.commit() (data won’t save)
• ❌ Missing comma in tuple → (“John”,)
• ❌ Typing "John" instead of ("John",)

Summary

• You inserted data into a table
• You stored real user information
• Your app can now remember data

In the next lesson, you’ll learn how to retrieve this data.