constant sql connection question

netfrugal

This is only a curiosity of mine, and may be a small matter.

Here is a connection script:

$connection = @mysql_connect("host", "username", "password"); 
$db = @mysql_select_db("DataBase", $connection);

And here is a simple query:

$sql = "UPDATE table1 SET column = 'something' WHERE adminID = '$adminID'";
mysql_query($sql,$connection) or die(mysql_error());

Do I really need to specify the $connection variable in that last line?

I've seen it done with and without. Any thoughts on why that is? Or is it for the possibility of using another database connection?

thanks!

laserlight

netfrugal wrote:
Do I really need to specify the $connection variable in that last line?

No, but it is arguably good practice.

netfrugal wrote:
I've seen it done with and without. Any thoughts on why that is? Or is it for the possibility of using another database connection?

Yes, it is for the possibility of having another database server connection. If you read the PHP manual's entry on [man]mysql_query/man, you will see that "if the link identifier is not specified, the last link opened by mysql_connect() is assumed", which is why you often can do without it.

If you look at the corresponding functions in the PDO and MySQLi extensions, you will see that this is no longer the case. You have to specify the connection object (obviously) or the connection link resource (in the case of the non-object based version of the MySQLi interface).