string('referral_code')->lenght(8)->nullable(); }); $existing_user = User::where('referral_code', '')->get(); foreach ($existing_user as $user) { $random = STR::random(8); if (User::where('referral_code', '=', $random)->doesntExist()) { DB::table("users") ->where("id", "=", $user->id) ->update(['referral_code' => $random]); }else{ $random = STR::random(8); DB::table("users") ->where("id", "=", $user->id) ->update(['referral_code' => $random]); } } } /** * Reverse the migrations. * * @return void */ public function down() { Schema::table('users', function (Blueprint $table) { $table->dropColumn('referral_code'); }); } }