Migrations foreign Key Issue

You should change

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

To

$table->unsignedInteger('grade_id')->unsigned();

Because foreign key cannot be nullable.

@DmytroOlefyrenko tried that .. but still have the same issue i changed the the field to what you asked me to do i.e $table->unsignedInteger('grade_id')->unsigned();

then i php artisan migrate:rollback then did composer dump-autoload and migrated again but still had the same problem

it migrates fine but still through's up that error definitely meaning something is wrong somewhere ..:-(

@rojonunoo Can you put here whole content of migration file, so can have more data. Also is grades table already exist?

public function up()
{
    Schema::create('students', function (Blueprint $table) {

        $table->engine = 'InnoDB';

        $table->increments('id');
        $table->unsignedInteger('grade_id')->unsigned();
        $table->string('name');
        $table->date('dob');
        $table->string('last_school_attended');
        $table->string('avatar')->default();
        $table->softDeletes('deleted_at');
        $table->timestamps();


        $table->foreign('grade_id')
            ->references('id')->on('grades')
            ->onDelete('cascade');

    });
}

public function down()
{
    Schema::dropIfExists('students');
}

}

class CreateGradesTables extends Migration {

public function up()
{
    Schema::create('grades', function (Blueprint $table) {
        $table->increments('id');
        $table->string('grade_name');
        $table->timestamps();
    });
}


public function down()
{
    Schema::dropIfExists('grades');
}

}

@DmytroOlefyrenko

@rojonunoo Make sure that you first run CreateGradesTables migration and then students table migration. To do it you can rename datetimes in migration file names. Because now you try create foreign key to grades table, which does not exist.

@DmytroOlefyrenko thanks so much I really appreciate the help .. so much it worked..