PHP MYSQL Depth Querying - php

Question

I'm new and I feel lost. Is this code doing a infinite loop?
Should I remove line 2-4? Is line 19 "$_row['employee_manager_id']," even important?
Any advice on how I should do this? Thank you.
function get_employees_by_hierarchy( $_employee_id = 0,$_depth = 0,$_org_array = array() ) {
if ( $this->org_depth < $_depth ) {
$this->org_depth = $_depth;
}
$_depth++;
$_query = "SELECT * FROM employees WHERE ";
if ( !$_employee_id ) {
$_query .= "employee_manager_id IS NULL OR employee_manager_id = 0";
}
else {
$_query .= "employee_manager_id = " . $this->dbh->quoteSmart( $_employee_id );
}
$_result = $this->query( $_query );
while ( $_row = $_result->fetchRow() ) {
$_row['depth'] = $_depth;
array_push( $_org_array, $_row );
$_org_array = $this->get_employees_by_hierarchy(
$_row['employee_manager_id'],
$_depth,
$_org_array
);
}
return $_org_array;
}

Answer 1

From the looks of it:
It does do an infinite loop. There isn't a terminating condition on the recursion. you need a condition that causes this:
$_org_array = $this->get_employees_by_hierarchy(
$_row['employee_manager_id'],
$_depth,
$_org_array
);
to not run, or at least to assign it to something that isn't get_employees_by_hierarchy.
after you fix that there it will be an infinite loop if an employee is their own manager at some point.
Impossible to say, is 'depth' used anywhere else? This function returns the $_org_array that has the 'depth' field but we can't see if it's used. It certainly isn't breaking anything in this code.
Without seeing sample data I'd say, yes it's important. The code recurses using the self referential employees table using the manager's id as the next level of the hierarchy.
put a check in before you assign the $_org_array that checks if the manager's id is null, if that happens do something like this: $_org_array = $this.