Can anyone tell me what is causing this error

Question

the email field in the database is Unique

    <?php
require_once("conexao.php");
$nome  = $_REQUEST['nome'];
$email =$_REQUEST['email'];
$telefone = $_REQUEST['telefone'];

 try{
 $conexao = new PDO($banco,$user,$senha);
     $sql = "INSERT INTO tb_crud2 (nome,email,telefone) VALUES ('$nome','$email','$telefone')";
     $registro = $conexao->query($sql);

     $row = $registro->rowCount();
  if ($row==1){
      echo "cadastrado com sucesso";
  }else{
      echo "este email já está cadastrado em nosso banco de dados";
  }
 }catch (PDOException $e){
     echo "erro ao se conectar";
 }

Answer 1

As @Leite said, the problem is that you are trying to record a duplicate data in a Row unique.

You can get around this by checking if there is value before:

$conexao = new PDO($banco,$user,$senha);
$registro = $conexao->query("SELECT * FROM tb_crud2 WHERE email = '$email'");

if ($registro->fetchColumn() == 0) //Email não cadastrado
{
    //Código do insert, etc
}
else //Email duplicado
{
    echo "este email já está cadastrado em nosso banco de dados";
}

Or check the code of the resulting error. When the error is by trying to insert duplicated data into a Unique column, the error generated has the code 1062:

$conexao = new PDO($banco,$user,$senha);
$registro = $conexao->query("INSERT INTO tb_crud2 (nome,email,telefone) VALUES ('$nome','$email','$telefone')");

if (!$registro && $conexao->errorCode() == '1062') //Retornou erro de dado duplicado
{
    echo "este email já está cadastrado em nosso banco de dados";
}
else
{
    //Código do insert, etc
}

Answer 2

Your query must be returning false, which is what the PDO::query returns when the query fails, if it was working, it should return a PDOStatement, that does not happen there.

The problem may be the email being repeated if it is unique in the database, but with the information of the question, this seems to be the most likely cause.