How Does ON DELETE CASCADE Affect Related Tables in MySQL Foreign Key Constraints?

MySQL Foreign Key Constraints with Cascade Delete

Foreign key constraints play a vital role in maintaining data integrity and preventing orphans in relational databases. In MySQL, you can use the ON DELETE CASCADE option to ensure that when you delete a parent record, related child records are automatically deleted as well.

To set up a foreign key constraint with cascade delete, consider the following tables:

In this setup, products has a foreign key referencing categories, and ON DELETE CASCADE is specified to automatically delete products when the referenced category is deleted. However, this cascade will only affect records in categories_products where the category_id matches the deleted category.

For example, if you have the following data:

If you delete the 'red' category:

The products table will not be affected because the cascade only applies to the categories_products table. As a result, the data will become:

This arrangement ensures that you can maintain referential integrity while avoiding unintentional deletion of unrelated records.

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