MySQL update using PDO and prepared statement not working

Question

I\'m having a strange problem with php PDO and mysql.

I have the following table:

create table test_table ( id integer, value text );

Answer 1

http://php.net/manual/en/pdo.prepare.php states:

You must include a unique parameter marker for each value you wish to pass in to the statement when you call PDOStatement::execute(). You cannot use a named parameter marker of the same name more than once in a prepared statement, unless emulation mode is on.

As this indicates, the likely reason behind your code working on one server and not another is that PDO::ATTR_EMULATE_PREPARES is disabled on the server which the code fails on. As the documentation says, this attribute effectively removes the restriction preventing you from using a parameter marker of the same name twice (along with some other restrictions).

Answer 2

try {
     $db = new PDO('mysql:host=localhost;dbname=vendor_management_system', 'root', '');
     $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
     $db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
}catch(PDOException $e) {
    echo 'ERROR: ' . $e->getMessage();
}




$fields[] = 'car_name';
$fields[] = 'model_no';
$fields[] = 'maker_id';
$fields[] = 'dealer_id';

$values[] = "testcar";
$values[] = "no#1";
$values[] = 2;
$values[] = 4;



echo SQLUpdate('car_details', $fields, $values,'car_id = 32 and car_name = "testname"',$db);




//START: SQLUpdate
//$fields = array of fields in DB
//$values = array of values respective to the $fields
 function SQLUpdate($table,$fields,$values,$where,$db) {



  //build the field to value correlation
  $buildSQL = '';
  if (is_array($fields)) {

        //loop through all the fields and assign them to the correlating $values
        foreach($fields as $key => $field) :
      if ($key == 0) {
            //first item
            $buildSQL .= $field.' = ?';
          } else {
            //every other item follows with a ","
            $buildSQL .= ', '.$field.' = ?';
          }
    endforeach;

  } else {
    //we are only updating one field
        $buildSQL .= $fields.' = :value';
  }

  $prepareUpdate = $db->prepare('UPDATE '.$table.' SET '.$buildSQL.'
WHERE '.$where);

  //execute the update for one or many values
  if (is_array($values)) {
    $affected_rows=$prepareUpdate->execute($values);
    return $affected_rows;
  } else {
    $affected_rows=$prepareUpdate->execute(array(':value' => $values));
    return $affected_rows;
  }


  //record and print any DB error that may be given
  $error = $prepareUpdate->errorInfo();
  if ($error[1]) print_r($error);

} 
//END: SQLUpdate

Answer 3

$maker_id=1;
$stmt = $db->prepare("UPDATE car_details SET maker_id=?");
$affected_rows=$stmt->execute(array($maker_id));
echo $affected_rows.' were affected';