迁移我的数据库时出现此错误,下面是我的代码,后面是我在尝试运行迁移时遇到的错误
public function up()
{
Schema::create('users', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->string('email')->unique();
$table->timestamp('email_verified_at')->nullable();
$table->string('password');
$table->rememberToken();
$table->timestamps();
$table->string('first_name')->nullable();
$table->string('last_name')->nullable();
$table->string('city')->nullable();
$table->unsignedBigInteger('role_id');
$table->foreign('role_id')->references('id')->on('roles')->onDelete('cascade');
});
}
/**
* Reverse the migrations.
*
* @return void
*/
public function down()
{
Schema::dropIfExists('users');
}