laravel foreign key constraint

1$table->unsignedBigInteger('user_id');
2$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');

1Schema::table('posts', function (Blueprint $table) {
2    $table->unsignedBigInteger('user_id');
3
4    $table->foreign('user_id')->references('id')->on('users');
5});
6OR
7Schema::table('posts', function (Blueprint $table) {
8    $table->foreignId('user_id')->constrained();
9});

1$table->foreign('column_name')->references('id')->on('table_name')->onDelete('cascade');

1Schema::table('posts', function (Blueprint $table) {
2    $table->unsignedBigInteger('user_id');
3
4    $table->foreign('user_id')->references('id')->on('users');
5});

1// Searched, laravel drop foreign column
2Schema::table('users', function (Blueprint $table) {
3    $table->dropColumn(['votes', 'avatar', 'location']);
4});

1public function up()
2{
3    Schema::create('replies', function (Blueprint $table) {
4        $table->bigIncrements('id');
5        $table->text('body');
6        $table->unsignedBigInteger('question_id');
7        $table->integer('user_id')->unsigned();
8        $table->foreign('question_id')->references('id')->on('questions')->onDelete('cascade');
9        $table->timestamps();
10    });
11}
12