PDO UPDATE array using php mysql - php

Question

Hello I'm trying to make a code to UPDATE or EDIT the survey answers and comments per answer but when I execute the function submiting the form, it did not save any value into the database. What can I do to fix it?
I'm new in PDO.
Thanks in advance.
Database Structure
"Questions" (idquestion, question)
"Surveys" (idsurvey, idquestion, answers, comments_per_question, survey_number)
Update function
public function ModifySurveyMulti($answer = array())
{
if(!empty($answer)) {
foreach($answer as $questi => $value ) {
$this->MyDB->Write("UPDATE survey SET(
`idquestion` = '".$questi."',
`answers` = '".$value[0]."',
`comments_per_answer`= '".$_POST["comment"][$questi]."')");
}
}
}
modify_surveyform.php
<th><?php echo $row["questions"];?></th>
<td>
<input type = "text"
name = "answer[<?php echo $row['idquestion'];?>][]"
value = "<?php echo $row["answers"];?>">
</input>
</td>
<td>
<Textarea type = "text"
name = "comment[<?php echo $row['idquestion'];?>]"
cols = "50" rows = "3"/> <?php echo $row["comment"];?
</textarea>
</td>
</tr><?php } ?>
Mydbconnect.php
<?php
// I'm adding my PDO database because yours is deprecated
class DBConnect
{
public $con;
// Create a default database element
public function __construct($host = '',$db = '',$user = '',$pass = '')
{
try {
$this->con = new PDO("mysql:host=$host;
dbname=$db",$user,
$pass, array(
PDO::ATTR_ERRMODE
=> PDO::ERRMODE_WARNING
)
);
}
catch (Exception $e) {
return 0;
}
}
// Simple fetch and return method
public function Fetch($_sql)
{
$query = $this->con->prepare($_sql);
$query->execute();
if($query->rowCount() > 0) {
while($array = $query->fetch(PDO::FETCH_ASSOC)) {
$rows[] = $array;
}
}
return (isset($rows) && $rows !== 0 && !empty($rows))? $rows: 0;
}
// Simple write to db method
public function Write($_sql)
{
$query = $this->con->prepare($_sql);
$query->execute();
}
}?>

Answer 1

Few things you need to do:
First of all ditch this code, it is useless and expose you to sql
injection
Use PDO directly with prepared statement
The query you need is :
UPDATE survey SET(`answers`= ?,`comments_per_answer`= ?) WHERE idquestion = ?
You will need to adjust your class to only create the connection
class DBConnect
{
public $con;
public function __construct($host = '',$db = '',$user = '',$pass = '')
{
try {
$this->con = new PDO(
"mysql:host=$host;dbname=$db",
$user,$pass,
array(PDO::ATTR_ERRMODE => PDO::ERRMODE_WARNING)
);
}
catch (Exception $e) {
die($e);
}
}
public function get_connection(){
return $this->con;
}
}
So that you can create it like this:
$db = new DBConnect(/*pass arguments here*/);
$this->MyDB = $db->get_connection();
Modify and use it in your function:
public function ModifySurveyMulti($answer = array(), $comments)
{
$sql = 'UPDATE survey SET(`answers`= ?,`comments_per_answer`= ?)
WHERE idquestion = ?';
$stmt->prepare($sql);
foreach($answer as $questi => $value ) {
$stmt->execute(array($value, $comments[$questi],$questi));
$count = $stmt->rowCount();
echo $count > 0 ? $questi.' updated' : $questi.' did not update';
}
}
Call the function :
if(isset($_POST['answer'], $_POST['comments'])){
$answers = $_POST['answer'];
$comments = $_POST['comments'];
ModifySurveyMulti($answers, $comments);
}