Why is creating Foreign Key in Laravel 5.8 failing? - mysql

Question

The migration script below was running smoothly in an older version of Laravel but I added it to my fresh Laravel 5.8 and ran the script. I'm getting Error: foreign key was not formed correctly
Evaluation Migration:
public function up() {
Schema::create('evaluation', function (Blueprint $table) {
$table->increments('id');
$table->integer('user_id')->unsigned()->index();
$table->timestamps();
$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
});
}
Users Migration:
public function up() {
Schema::create('users', function (Blueprint $table) {
$table->bigIncrements('id');
$table->timestamps();
});
}

Answer 1

As we discussed in the comments above, a foreign key column must be the same data type as the primary key it references.
You declared your user.id primary key as $table->bigIncrements('id') which becomes BIGINT UNSIGNED AUTO_INCREMENT in MySQL syntax.
You must declare the foreign key as $table->unsignedBigInteger('user_id') which will become BIGINT UNSIGNED in MySQL, making it compatible with being a foreign key to the user.id column.

Answer 2

update your `integer('user_id')` to `bigInteger('user_id')`
public function up() {
Schema::create('evaluation', function (Blueprint $table) {
$table->increments('id');
$table->bigInteger('user_id')->unsigned()->index();
$table->timestamps();
$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
});
}