INSERT, UPDATE, and DELETE
Explore how to safely modify database data using SQL commands INSERT, UPDATE, and DELETE. Learn to verify changes with SELECT queries and apply AI guidance to avoid common mistakes. This lesson helps you confidently handle dynamic data updates with best practices and practical exercises.
Step 1: Start with a big idea
Until now, your SQL queries have been non-destructive; they only read from the database. But every database needs to evolve:
New customers get added.
Prices get updated.
Old data gets cleaned up.
So now we shift from asking to acting. Before writing any query, remember this golden rule: When modifying data, clarity beats speed.
You’ll always verify your query logic before execution, with AI as your safety partner.
Step 2: Adding new data (INSERT)
Let’s start simple. Say you have a table called employees with these columns: | id | first_name | ...