Foreign key constraint fails - how to delete safely related entities in Laravel

Question:

say this is an example:

Use has time sheet configurations.

One of the user is project manager.

Project manager manages many departments.

User (1) - configuration (many)

User (1) - departments(many)

I used ' onDelete('cascade') in the configuration dedicated for the user. but I don't want to delete the department.

So is it okay to make a null?

Then how to make a null value ? in the migration file?

Solution:

You should be able to use onDelete('set null') in the foreign key relation, but it is important to make sure that the field is also set to nullable.

For example:

$table->unsignedInteger('user_id')->nullable();

$table->foreign('user_id')->references('id')->on('users')->onDelete('set null');