Error in database connection

Question

I’m doing a project and this with a problem in the database part. I created a form to register on the site, but when you put all the data to register, this information is not passed to the database. Can anyone tell me what might be wrong ?

form

            <div class="col-md-6 logo">
            Cadastre-se
            <form method="post" action="registra.php" id="cadastro">
                <br>
                <div class="form-group">
                    <input type="text" class="form-control" id="nome" name="nome" placeholder="Digite seu nome completo" required="requiored">
                </div>
                <br>
                <div class="form-group">
                    <input type="email" class="form-control" id="email" name="email" placeholder="Email" required="requiored">

                    <?php
                    if($erro_email){
                    echo '<font size="3px" color="#FF0000"> Esse email ja esta sendo usado em outra conta!</font>';
                }

                ?>
            </div>
            <br>
            <div class="form-group">
                <input type="password" class="form-control" id="senha" name="senha" placeholder="Crie uma senha" required="requiored">
            </div>


            <button type="submit" class="btn btn-default ">Cadastrar</button>
        </form>
        </div>

Connection to the database

<?php

require_once('bancodedados.php');

 $usuario = $_POST['usuario'];
 $email = $_POST['email'];
 $senha = md5($_POST['senha']);

$objDB = new db();
$link = $objDB->conecta_mysql();

$email_existe = false;

$sql = "insert into usuarios(usuario, email, senha) values ('$usuario','$email','$senha')";

//verificar se o email ja existe
$sql = "select * from usuarios where email = '$email'";
if($resultado_id = mysqli_query($link, $sql)){

    $dados_usuario = mysqli_fetch_array($resultado_id);

    if (isset($dados_usuario['email'])) {
        $email_existe = true;
    }  
} else {
    echo ' erro ao tentar localizar o email';
}

    if($email_existe){

        $retorno_get ='';

        $retorno_get.="erro_email=1&";

        header('Location:cadastreentrar.php?'.$retorno_get);
die();
    }

//executar querry
if(mysqli_query($link, $sql)){
    header('Location:home.php');
} else {
    echo 'Não foi possivel registrar o usuario';
}

?>

Answer 1

You are not running the Insert query, only the select query. Let’s go to the table test:

$sql = "insert into usuarios(usuario, email, senha) values ('$usuario','$email','$senha')";
//Criou a string do insert, chamada sql, e atribui o insert

$sql = "select * from usuarios where email = '$email'";
//Atribuiu o select para o sql (que continha o insert)

if($resultado_id = mysqli_query($link, $sql)){
//Executou o comando do sql (select)

Notice what you did? You created the command to insert the values into the database, but did not execute it, you overwritten another string over it.

To fix it, do it this way:

$sql = "select * from usuarios where email = '$email'";

if($resultado_id = mysqli_query($link, $sql)){ //Executa o select

    $sql2 = "insert into usuarios(usuario, email, senha) values ('$usuario','$email','$senha')";

    mysqli_query($link, $sql2); //Executa o insert
}

Tip: Your code is too complex to run things so simple, try to improve it and optimize it.