PHP: check whether items in the database have the same name

Question

I am creating a PHP script that checks if your database contains an element with the same name. Here's the code:

<?php

$query = @mysql_query("SELECT * FROM category");

while($Row = mysql_fetch_array($query)) {
    $ID = $Row['id'];
    $Name = $Row['name'];
}

// fetch the value of the name field
$CategoryName = $_GET['name'];

if($CategoryName === $Name) {
    echo "here is an element with the same name";
}

?>

Why doesn't it work? Where is the error? Sorry for my English, I'm Italian.

please read this before proceeding with your code http://stackoverflow.com/questions/12859942/why-shouldnt-i-use-mysql-functions-in-php — open source guy, Jun 07 '13 at 04:41

score 3 · Answer 1 · edited Jun 07 '13 at 04:41

3

If you only want to know if the element exists or not, you can change your query to be much more efficient.

$query = mysql_query("SELECT COUNT(Name) FROM category WHERE Name = '" . mysql_real_escape_string($_GET['name']) . "'");
$row = mysql_fetch_array($query);
if ($row[0]) {
  echo "here is an element with the same name";
}

edited Jun 07 '13 at 04:41

Yogesh Suthar

30,424
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answered Jun 07 '13 at 04:39

hw.

790
4
10

score 2 · Answer 2 · answered Jun 07 '13 at 04:36

If there are multiple items being returned from the database, you need to wrap your logic within the while:

// fetch the value of the name field
$CategoryName = $_GET['name'];

while($Row = mysql_fetch_array($query)) {
    $ID = $Row['id'];
    $Name = $Row['name'];

    if($CategoryName === $Name) {
        echo "here is an element with the same name";
    }
}

score 0 · Answer 3 · answered Jun 07 '13 at 04:44

Use the below code:

$query = @mysql_query("SELECT * FROM category");

$flag = false; // I am using a flag variable

// fetch the value of the name field
$CategoryName = $_GET['name'];

 while($Row = mysql_fetch_array($query)) {
    $ID = $Row['id'];
    $Name = $Row['name'];
    if($CategoryName === $Name) {
       $flag = true;
    }
}

if($flag) {
    echo "here is an element with the same name";
}
?>

This is also a trick to check the name in database.

score 0 · Answer 4 · answered Jun 07 '13 at 04:47

I think the optimize way will be use count aggregate function in mysql to match how many rows match to your given name. This can be done in two ways.

$query = mysql_query("SELECT COUNT(Name) FROM category WHERE Name = '" .      mysql_real_escape_string($_GET['name']) . "'");
 $row = myqsl_fetch_array($query);
 if ($row[0]) {
      echo "here is an element with the same name";
   }

or by this

$query = mysql_query("SELECT Name FROM category WHERE Name = '" .      mysql_real_escape_string($_GET['name']) . "'");
 $row = mysql_num_rows($query);
 if ($row>0) {
      echo "here is an element with the same name";
 }

It does not work. I have write: $query = mysql_query("SELECT name FROM category WHERE name = '" . mysql_real_escape_string($_GET['name']) . "'"); $row = mysql_num_rows($query); if ($row>0) { echo "here is an element with the same name"; } else { $sql = "INSERT INTO category (name) VALUES ('".$_REQUEST['name']."'; } — Simone Cognom, Jun 07 '13 at 05:05

PHP: check whether items in the database have the same name

4 Answers4