PHP Try and Catch for SQL Insert

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I have a page on my website (high traffic) that does an insert on every page load.

I am curious of the fastest and safest way to (catch an error) and continue if the system is not able to do the insert into MySQL. Should I use try/catch or die or something else. I want to make sure the insert happens but if for some reason it can't I want the page to continue to load anyway.

...
$db = mysql_select_db('mobile', $conn);
mysql_query("INSERT INTO redirects SET ua_string = '$ua_string'") or die('Error #10');
mysql_close($conn);
...
10 Answers

Checking the documentation shows that its returns false on an error. So use the return status rather than or die(). It will return false if it fails, which you can log (or whatever you want to do) and then continue.

$rv = mysql_query("INSERT INTO redirects SET ua_string = '$ua_string'");
if ( $rv === false ){
     //handle the error here
}
//page continues loading

if you want to log the error etc you should use try/catch, if you dont; just put @ before mysql_query

edit : you can use try catch like this; so you can log the error and let the page continue to load

function throw_ex($er){  
  throw new Exception($er);  
}  
try {  
mysql_connect(localhost,'user','pass'); 
mysql_select_db('test'); 
$q = mysql_query('select * from asdasda') or throw_ex(mysql_error());  
}  
catch(exception $e) {
  echo "ex: ".$e; 
}

To catch specific error in Mysqli


$conn = ...;
$q = "INSERT INTO redirects (ua_string) VALUES ('$ua_string')";
if (mysqli_query($conn, $q)) {
    // Successful
}
else {
    die('Mysqli Error: '.$conn->error); // Show Error Complete Description
}

mysqli_close($conn);

Use any method described in the previous post to somehow catch the mysql error.
Most common is:

$res = mysql_query('bla');
if ($res===false) {
  //error
  die();
}
//normal page

This would also work:

function error() {
  //error
  die()
}
$res = mysql_query('bla') or error();
//normal page

try { ... } catch {Exception $e) { .... } will not work!

Note: Not directly related to you question but I think it would much more better if you display something usefull to the user. I would never revisit a website that just displays a blank screen or any mysterious error message.

$new_user = new User($user);
$mapper = $this->spot->mapper("App\User");

try{
    $id = $mapper->save($new_user);     
}catch(Exception $exception){

    $data["error"] = true;
    $data["message"] = "Error while insertion. Erron in the query";
    $data["data"] = $exception->getMessage();

    return $response->withStatus(409)
    ->withHeader("Content-Type", "application/json")
    ->write(json_encode($data, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT));        
}

if error occurs, you will get something like this->

{
    "error": true,
    "message": "Error while insertion. Erron in the query",
    "data": "An exception occurred while executing 'INSERT INTO \"user\" (...) VALUES (...)' with params [...]:\n\nSQLSTATE[22P02]: Invalid text representation: 7 ERROR:  invalid input syntax for integer: \"default\"" }

with status code:409.

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