Question

I have query below:

$r = "Query goes here...";
$r = conn::execq($q);
while($fetch = mysqli_fetch_array($r)) {
   $q = "Query goes here..."; //The $fetch value above is inserted here as 'WHERE' clause
   $r = conn::execq($q); //--> The problem
   $r = mysqli_fetch_row($r);

   if($r > 0) print "ok<br/>";
   else print "failed<br/>";
}

And in class “conn” function “execq“:

public static function execq($q) {
    $dbc = @mysqli_connect(DB_HOST, DB_USER, DB_PASS, DB_NAME) OR die ('Could not connect to MySQL: ' . mysqli_connect_error());
    $r = mysqli_query($dbc, $q);
    mysqli_close($dbc);
    return $r;
}

The execq function doesn’t called after some looping. The first query has been executed successfully, and then the second query being executed. After some looping, the query being stopped to called the function “conn::execq”. Any ideas? Thanks..

— EDIT —

conn:openconn(); //Open connection   

$r = "Query goes here...";
$r = conn::execq($q);
while($fetch = mysqli_fetch_array($r)) {
   $q = "Query goes here..."; //The $fetch value above is inserted here as 'WHERE' clause
   $r = conn::execq($q); //--> The problem
   $r = mysqli_fetch_row($r);

   if($r > 0) print "ok<br/>";
   else print "failed<br/>";
}

conn:closeconn(); //Close connection

And in class “conn“:

public static function openconn() {
    global $dbc;
    $dbc = @mysqli_connect(DB_HOST, DB_USER, DB_PASS, DB_NAME) OR die ('Could not connect to MySQL: ' . mysqli_connect_error());
}

public static function closeconn() {
    mysqli_close($dbc);
}

public static function execq($q) {        
    $r = mysqli_query($dbc, $q);        
    return $r;
}

And now I’ve got:

Notice: Undefined variable: dbc in ...
Warning: mysqli_error() expects parameter 1 to be mysqli, null given in ...

Answer 1

1. You are opening and closing the database connection several times in very short order; this is horribly inefficient. Keep reusing one open connection!
2. You are trying to use mysqli_fetch_row on a resource after its connection has already been closed. This should not work at all.
3. You are overwriting the resource $r inside your loop, so the resource $r in your while condition will not yield any more results and the iteration ends.
4. You should try to make one slightly more complex SQL query to get the information you want instead of generating more and more queries by looping over the result of the first query. The database can often do much more work for you than you think.