Question

I have 2 arrays, $arr for the old menu name, and $arr1 for the new menu name. I want to replace the old menu name with the new in my database. I have the following code but it throws out an error.

<?php
$arr  = explode(',', preg_replace('/^.*\[(.*)\].*$/', '$1', trim($_POST['menuname'],
                                                                 '[]')));
$arr1 = explode(',', preg_replace('/^.*\
       [(.*)\].*$/', '$1', trim($_POST['editmainmenu'], '[]')));

mysql_connect("localhost", "root", "root");
mysql_select_db("test");
foreach ($arr as $key => $value)
{
    $value1 = $arr1[$key];

    mysql_query("update test set (menuname) =('" .
                    mysql_real_escape_string($value1) . "') where menuname=('" .
                    mysql_real_escape_string($value) . "')")or
        die('unable' . mysql_error());
    echo "updated";
}
?>

I get the following error:

04-09 19:06:27.201: I/System.out(1291): unableYou have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(menuname) =('') where menuname=('Food Menu')' at line 1

Please tell me how to solve this issue. Thanks!

Answer 1

This is what your code looks like after the cleanup I did to it:

<?php
$old_menu_names = explode(',',
                          preg_replace(
                              "|\[(.+)\]|",          //Find the part in between the square brackets
                              "$1",                  //And extract it
                              trim(
                                  $_POST['menuname'] //From the trimmed menuname.
                              )
                          )
);
$new_menu_names = explode(',',
                          preg_replace(
                              "|\[(.+)\]|",
                              "$1",
                              trim(
                                  $_POST['editmainmenu']
                              )
                          )
);

mysql_connect("localhost", "root", "root");
mysql_select_db("test");
foreach ($old_menu_names as $key => $old_name)
{
    $new_name = mysql_real_escape_string($new_menu_names[$key]);
    $old_name  = mysql_real_escape_string($old_menu_names[$key]);

    mysql_query("UPDATE `test` SET `menuname` = '$new_name' WHERE menuname = '$old_name'")
        or die('Error' . mysql_error());
    echo "Updated";
}
?>

##What I did:

• Variable naming – Name your variables according to what they contain, don’t use obscure names such as $arr or $arr1, in larger applications, you’ll be lost in no time.
• If a statement is long, complex, and/or contains nested brackets, don’t be afraid to line break it so that it would be easier to follow.
• Comments, when something is not immediately understood, feel free to add comments explaining to anyone (including yourself in a few months) what the code is intended to do.
• Don’t add brackets where they’re not needed. See the new query I wrote.
• You didn’t declare the old name inside your foreach loop, so that came out empty the threw an error.

In short, I suggest you read a good book about best practices and programming concepts.