What are some SQL queries for database normalization?

What are some SQL queries for database normalization?

Normalization is the process of organizing data to reduce redundancy. Here are some SQL queries for different normalization forms.

Can you give me an example of a query for 1NF?

Sure! To achieve 1NF, you can use a query like this: SELECT DISTINCT column1, column2 FROM table_name; This ensures that each column contains atomic values.

What about 2NF? How do I write a query for that?

For 2NF, you need to ensure that all non-key attributes are fully functional dependent on the primary key. You might use a query like: SELECT column1, column2 FROM table_name WHERE primary_key_column = value; to isolate those dependencies.

And for 3NF?

In 3NF, you eliminate transitive dependencies. A query example could be: SELECT column1, column2 FROM table_name WHERE non_key_column IS NOT NULL; This helps ensure that non-key attributes depend only on the primary key.