update don't work if something is not diferent - php

Question

If i don't change at least 1 of the fields values, the update fails.
Insert works ok.
My git
https://github.com/emerson-cs-santos/TSI-PI_2-2019/blob/master/PHP/novo_user.php
If i keep doing this:
$status = $status . ' ';
works, but it's sound me the right solution
-- MYSQL --
CREATE DATABASE IF NOT EXISTS SENAC_PI;
USE SENAC_PI;
CREATE TABLE IF NOT EXISTS USUARIOS
(
codigo INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY
,nome VARCHAR(20) NOT NULL
,senha VARCHAR(200) NOT NULL
,tipo VARCHAR(20) NOT NULL
)
;
-- PHP --
<?php
// Open a Connection to MySQL
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "SENAC_PI";
// Create connection
$conn = new mysqli($servername, $username, $password,$dbname);
// Check connection
if ($conn->connect_error)
{
die("Connection failed: " . $conn->connect_error);
echo 'errado';
return;
}
$query = 'use SENAC_PI';
$result = $conn->query($query);
$codigo = 0;
$login = 'teste';
$senha = '123';
$status = 'Ativo';
$query =
" INSERT INTO USUARIOS ( codigo, nome, senha, tipo ) Values (?, ?, ?, ?)";
$querytratada = $conn->prepare($query);
$querytratada->bind_param("isss",$codigo,$login,$senha,$status);
$querytratada->execute();
if ($querytratada->affected_rows > 0)
{
$resposta = 'ok';
}
else
{
$resposta = 'erro';
}
-- update
$query =
" UPDATE USUARIOS SET nome = ? ,senha = ? , tipo = ? where codigo = ? ";
$querytratada = $conn->prepare($query);
$querytratada->bind_param("sssi",$login,$senha,$status,$codigo);
$querytratada->execute();
if ($querytratada->affected_rows > 0)
{
$resposta = 'ok';
}
else
{
$resposta = 'erro';
}
}
?>
If i don't change at least 1 of the fields values, then query returns: affected_rows = 0

Answer 1

Thanks to Nigel, i managed to verif the result.
I was using "affected_rows" to valid for errors, but if the user doesn't change something, my code will return as an error.
Using "Rows matched" and "Warnings", i can make sure that my query doesn't have errors.
My final code for the problem:
preg_match_all ('/(\S[^:]+): (\d+)/', $conn->info, $querytratada);
$info = array_combine ($querytratada[1], $querytratada[2]);
// Linhas encontradas com base na condição da where
$linhas_encontradas = $info['Rows matched'];
// Linhas que foram alteradas, quando os dados não forem alterados, mesmo o comando estando certo, não é retornado linhas afetadas
$linhas_afetadas = $info['Changed'];
// Avisos de problemas
$avisos_problemas = $info['Warnings'];
//if ($querytratada->affected_rows > 0)
if ($linhas_encontradas == '1' and $avisos_problemas == '0')
{
$resposta = 'ok';
}
else
{
$resposta = 'erro';
}
Anyway, thanks again Nigel!