Database username, id lookup

Just realised I have no idea what the output of the lookup would look like, , so another question if I may.

$db->query("SELECT id, username FROM ".$db->prefix."users");

What would the actual output look like? Apologies for asking so many questions.

Matt

Smartys wrote:

elbekko wrote:

Maximum size is the same as the int size on your system I think.

I think it's limited only by the memory your scripts are allocated

Right. Numpty mode on. What's a theoretical guess, (username, id), for a standard setup, then? The last two answers completely befuddled me.

Smartys wrote:

You would have to use $db->fetch_assoc($result) or $db->fetch_row($result) to get at the actual data

So I assume that would mean it's getting back to multiple database lookups, then? Must admit, until I've started looking at this idea, I hadn't realised just quite how convoluted it is. Php has more features than you can shake a stick at, but it definitely doesn't do anything the easy way.

No, it's not very complicated at all and doesn't involve any more database lookups. It sounds like I need to explain the way things work
When you do $db->query, it returns a resource. That resource can then be given to certain functions (in PunBB's abstraction layer, $db->fetch_assoc and $db->fetch_row are 2 examples) which will allow you to traverse the data.
Your code using $db->fetch_assoc would look something like

$result = $db->query("SELECT id, username FROM ".$db->prefix."users") or error('Could not get user list', __FILE__, __LINE__, $db->error());

$users = array();
while($user = $db->fetch_assoc($result))
    $users[$user['id']] = $user['username'];

Your code using $db->fetch_row would look something like

$result = $db->query("SELECT id, username FROM ".$db->prefix."users") or error('Could not get user list', __FILE__, __LINE__, $db->error());

$users = array();
while(list($id, $username) = $db->fetch_row($result))
    $users[$id] = $username;

Smartys wrote:

No, it's not very complicated at all and doesn't involve any more database lookups. It sounds like I need to explain the way things work
When you do $db->query, it returns a resource. That resource can then be given to certain functions (in PunBB's abstraction layer, $db->fetch_assoc and $db->fetch_row are 2 examples) which will allow you to traverse the data.
Your code using $db->fetch_assoc would look something like

$result = $db->query("SELECT id, username FROM ".$db->prefix."users") or error('Could not get user list', __FILE__, __LINE__, $db->error());

$users = array();
while($user = $db->fetch_assoc($result))
    $users[$user['id']] = $user['username'];

Your code using $db->fetch_row would look something like

$result = $db->query("SELECT id, username FROM ".$db->prefix."users") or error('Could not get user list', __FILE__, __LINE__, $db->error());

$users = array();
while(list($id, $username) = $db->fetch_row($result))
    $users[$id] = $username;

Thanks ever so much for that. I *think* I've seen the light now. So the basic way that it works is that the initial lookup creates the resource info and connection used by the second lookup. The second lookup then allows you to scroll through the data, (using the while loop), assigning the required info from each row from the table to an array, then terminating the db connection once you have scrolled through, and extracted, the required data? Have I grasped the correct gist of how it works?

Thanks ever so much for your help, BTW. Until around three weeks ago I'd never touched php before, so my learning curve does tend to go awry on occasion.