SQLSTATE[42S21] Error Why are foreign keys not being set?

Question

Laravel

I form a migration to change the table

php artisan make:migration ChangeArticlesTable --table=articles

The migration is successful.
Next, I open the migration file, make entries on the formation of foreign keys

$table->integer('user_id')->unsigned()->default(1);
     $table->foreign('user_id')->references('id')->on('users');         
     $table->integer('category_id')->unsigned()->default(1); 
     $table->foreign('category_id')->references('id')->on('categories');

Next, you need to make changes with the command
php artisan migrate
But the changes are not made, an error message appears:

[Illuminate\DATABASE\QueryException]
SQLSTATE[42S21]: COLUMN already EXISTS: 1060 Duplicate COLUMN name 'user_id' 
(SQL: ALTER TABLE 'articles' ADD 'user_id' INT UNSIGNED NOT NULL DEFAULT ‘1’, ADD 'catego ry_id' INT UNSIGNED NOT NULL DEFAULT ’l’)
[PDOException]
SQLSTATE[42S21]: COLUMN already EXISTS: I960 Duplicate COLUMN name ’user_id'

I don’t understand why foreign keys are not installed, what am I doing wrong? The error points to existing columns, naturally, they exist and I do not intend to change them. The task is to establish foreign keys.

Answer 1

uhmm, so what? the religion does not allow to create at once the table with keys?

Answer 2

Schema::table('articles', function ($table) {
           $table->foreign('user_id')
                ->references('id')->on('users');

            $table->foreign('category_id')
                ->references('id')->on('categories');
        });