Correct use of mysqli_real_escape_string for insert,select and update statement - PHP/Oracle

Question

I need to know if this code works when a user update,insert or search for something in my database. I'm not familiar with mysqli_real_escape_string yet.

Do i need to use $_SESSION here if we're talking about user input ?

       $connmaj = new mysqli();

       if ($connmaj->connect_error) {
           die("Connection failed: " . $connmaj->connect_error);
       }    


   //select
            $titreItem = mysqli_real_escape_string($link, 
   $_REQUEST['TITRE_ITE']);
           $donateurIte = mysqli_real_escape_string($link, 
   $_REQUEST['DONATEUR_ITE']);
            $mntValeurIte = mysqli_real_escape_string($link, 
   $_REQUEST['MNT_VALEUR_ITE']);

            $sqlSelectItem = "select $titreIte, $donateurIte, 
   $mntValeurIte from TP2_ITEM where EST_ARCHIVEE_ENC != 'Archivé'";    

           if ($connmaj->query($sqlSelectItem) === TRUE) {
                echo "Succes";
            } else {
                echo "Error: Aucune information retrouvée." . 
              $connmaj- >error;
            }
// insert

$noItem =   mysqli_real_escape_string($link, $_REQUEST['NO_ITEM']);
        $noEncan = mysqli_real_escape_string($link, $_REQUEST['NO_ENCAN']);
        $noItemEncanItem = mysqli_real_escape_string($link, $_REQUEST['NO_ITEM_ENCAN_ITE']);
        $titreItem = mysqli_real_escape_string($link, $_REQUEST['TITRE_ITE']);
        $cheminPhotoIte = mysqli_real_escape_string($link, $_REQUEST['CHEMIN_PHOTO_ITE']);
        $descIte = mysqli_real_escape_string($link, $_REQUEST['DESC_ITE']);
        $donateurIte = mysqli_real_escape_string($link, $_REQUEST['DONATEUR_ITE']);
        $mntValeurIte = mysqli_real_escape_string($link, $_REQUEST['MNT_VALEUR_ITE']);
        $mntPrixDepartIte = mysqli_real_escape_string($link, $_REQUEST['MNT_PRIX_DEPART_ITE']);
        $mntIncrementMiniIte = mysqli_real_escape_string($link, $_REQUEST['MNT_INCREMENT_MINI_ITE']);
        $mntAchatImmediatIte = mysqli_real_escape_string($link, $_REQUEST['MNT_ACHAT_IMMEDIAT_ITE']);
        $estFermeIte = mysqli_real_escape_string($link, $_REQUEST['EST_FERME_ITE']);
        $estPayeIte = mysqli_real_escape_string($link, $_REQUEST['EST_PAYE_ITE']);

        $sqlInsertItem = "insert into TP2_ITEM values ('$noItem','$noEncan','$noItemEncanItem','$titreIte',
'$cheminPhotoIte','$descIte','$donateurIte','$mntValeurIte',
 '$mntPrixDepartIte','$mntIncrementMiniIte','$mntAchatImmedi .     atIte,'$estFermeIte','$estPayeIte')";


        if ($connmaj->query($sqlInsertItem) === TRUE) {
            echo "Insertion réussie";
        } else {
            echo "Clé primaire dupliquée" . $connmaj->error;
        }

Im excepting to return what the users enter in my application.

Answer 1

There is no connection between $_SESSION AND mysqli_real_escape_string Function.

mysqli_real_escape_string() function escapes special characters in a string for use in an SQL statement