MySQL connection avail in functions?

Anon

Okay, here's my situation.
In a script, i open the connection to the database and then use it in queries here and there throughout the script. Then comes a function that needs that same connection. It seems that connection should be available to the queries inside the function but it's not - something like this:

::
mysql_select_db( [needed bla info] );

include(functions.php);

$query = mysql_query();
$result = mysql_fetch_array($query);

function_needing_db();

mysql_close()
::

now inside function_needing_db(), it looks something like:

function function_needing_db(){
$query = mysql_query();
$result = mysql_fetch_array($query);
return $result["field"];
}

the database connection created at the top of the acutal script page doesn't appear to be available to the function when it is called.

I tried putting mysql_select_db( [bla] ) in an include and including it in the function defintion too, and it didn't work.

Does this just mean I need to repeat mysql_select_db() in the function definitions too? Is there a better way than opening all these database connections?

Anon

When you do your mysql_connect() call you should capture the returned resource:

$db = mysql_connect();

Then you can pass this resource into the functions that need database connectivity.

If you look at all of the mysql functions you will see that they all have an optional resource link_identifier parameter, this is the $db that I created above. If you pass this around you will be better able to debug your code, and will always know what database any particular mysql() call is using.

edwardsbc

In fact, you really should test $db to be sure your connection attempt actually worked:

$db=mysql_connect(....);
if (!$db) { die "DB connection failed"; }

Anon

Instead of passing the $db as a parameter of a function, you can declare this var as global inside the function.

function somefunc () {

global $db;
$query = mysql_query("your query here", $db);
...

}

Anon

Yes you can declare it global, but that's not the best way to handle it. You should always try to compartmentalize your code as much as possible.

And Craig is right you should test for a successful connection (I guess I'm just too lazy ;->).