SQL inside a function?

_sh

Guys,

I'm building an application, each page of the app has two includes at the very top, an 'ini' type include that includes the 'conn' DB connection and Table selection config (so that each page can access the DB without having to connect each time), the other include is full of functions.

Now I'm writing the first function that interacts with the DB but for some reason, its sparking a...

"Warning: mysql_query(): supplied argument is not a valid MySQL-Link resource"

I've taken the same recordset generating code out of the function and dumped it raw onto one of the pages, and it works fine.

Now if I take the DB connection strings out of the 'ini' include and shove that within the function, all works well.

So I am assuming that for some reason PHP functions can't access variables that are included within another include. Do I have to declare my variables as globals or something?

Bit new to this!

Cheers, Ash

NogDog

I would recommend passing the connection resource as an additional function argument, as this is cleaner than dealing with globals. For example:

function myFunc($value, $dbConnx)
{
    $sql = "SELECT * FROM table WHERE something = '" . mysql_real_escape_string($value) ."'";
    $result = mysql_query($sql, $dbConnx);
}

// main code:
$connx = mysql_connect($dbhost, $dbuser, $dbpass);
$string = "This is a test.";
myFunc($string, $connx);

_sh

Ahhhh, nice idea - so by passing the variable $conn (in my case) to the function, its coming from the 'main page' and so available to the function within the include? If I'm understand that correctly?

Cheers, Ash

NogDog

The basic issue is that by default, functions have their own "name space", so variables defined outside of them are invisible within the function unless either (a) you pass them to the function via the parameter list, (b) the variable is already a "super global" (such as $_POST), or (c) you use the [man]global[/man] command within the function to specify that a variable is to be accessed from the script's global scope.

Option "c" is generally the weakest solution, as it creates a close coupling between the function and the script(s) that use it, making it both difficult to re-use in other scripts and difficult to debug in certain situations. Thus my recommendation that you pass the variable as a parameter, which keeps it obvious what is happening. (You can tell from the function declaration what variables external to the function are being passed to it for its use.)

_sh

Just to say thanks dude, you've saved the day and that all works fine!! Thanks mate!