deleting row from server

[Marius Miliunas]

The error's in the query, but the $primary is correct I just don't get wats wrong

$primary = $_POST['primary'];

$dbc = mysqli_connect('localhost','Marius','password','test')
	or die('Error connecting to server');
	
$query = 'DELETE FROM contact_messages WHERE PRIMARY KEY = "' . $primary . '"';
	
$result = mysqli_query($dbc,$query)
	or die('Error querying server');
	
echo $result;
	
mysqli_close($dbc);

[NogDog]

Why not have PHP/MySQL tell you what the problem is:

$result = mysqli_query($dbc,$query)
    or die("Error querying server:<br />\n" . mysqli_error() . "<br />$query"); 

[Marius Miliunas]

So I've interchanged PRIMARY KEY with the columns name 'index' but it just returns

Error querying server:<br />
<br />DELETE FROM contact_messages WHERE PRIMARY KEY = "2"

[NogDog]

Oops, I forgot the mysqli_error() needs the link as the argument:

mysqli_error($dbc) 

However, I'm pretty sure the problem is that you need a column name in your WHERE clause, not the keywords PRIMARY KEY.

[Marius Miliunas]

so i'm guessing index must be some sort of keyword in SQL cuz i changed it to 'id' and it works fine now

[NogDog]

Probably it is a reserved word. But you could still use it if you wanted to by "quoting" it with back-ticks (a.k.a. left quotes):

. . . WHERE `index` = . . .

[Dasher]

I have had problems in the past when deleting a row where the index was being auto incremented. It seemed the numbers got all bollixed up. I don't recall the exact problem now, but I ended up adding a column that indicated whether the row was active or not; ActiveID = 0 (inactive), 1 (active). Then added to queries ... WHERE ActiveID = 1 AND ...

[Marius Miliunas]

Well for that I'm using AJAX, so the $primary variable is sent directly from the object.index from the database so it always matches up correctly