php - (Laravel 8) errno: 150 "Foreign key constraint is incorrectly formed

Question

I want to create a table that assists users to read the topics that order by categories; also, users select the categories that they want in order to see the interest topics associated with categories. For instance, when users go to BBC, they can see the topics that they want to see from categories.

---

categories Table

id	name
1	sports
2	Tech

question from:https://stackoverflow.com/questions/65833074/laravel-8-errno-150-foreign-key-constraint-is-incorrectly-formed

Answer 1

Please read the documentation first.
https://laravel.com/docs/8.x/migrations#foreign-key-constraints

The foreignId method is an alias for unsignedBigInteger while the constrained method will use conventions to determine the table and column name being referenced. If your table name does not match Laravel's conventions, you may specify the table name by passing it as an argument to the constrained method:

The issue is that you're providing the table name as 'cascade' instead of 'users'.
i.e

//Should be...
$table->foreignId('user_id')->constrained('users');
//Instead of...
$table->foreignId('user_id')->constrained('cascade');

Don't forget to correct the 'category_id' as well.

If you really wish to apply 'cascade' options, try:

$table->foreignId('user_id')
      ->constrained()
      ->onUpdate('cascade')
      ->onDelete('cascade');