如何用PHP表示一个很大的数字？

Question

Hi I'm trying paginate a data without creating so many functions. I decided to merge the function (one loading some question and one for loading all the question) that takes all the data from my database.

I have this function call for my pagination:

$this->get_questions_incrementally(null, $id, $page_no, $items_per_page);

I usually do this when getting all the questions at once:

$this->get_questions_incrementally(null, $id, $page_no=0, $items_per_page=999999);

How do I represent $items_per_page to be infinity?

Am I doing a very bad idea and is there actually a better solution than this?

Answer 1

My recommendation would be to have a sentinel value. You don't really want to fetch an infinite number of rows. You want ALL the rows.

If you have control over the method you're calling, a reasonable thing to do would be to accept $items_per_page = -1 as a sentinel value indicating that you want ALL the results.

Alternatively, if you don't have control over that code, then as @zerkms suggested, I'd use PHP_INT_MAX.

This could be implemented like so

function get_questions_incrementally($a, $id, $page_number, $items_per_page) {
    if ($items_per_page == -1) { 
        $LIMIT = "";
    } else { 
       $LIMIT = " LIMIT $items_per_page"; 
    }
    //blah blah query building
    //at this point $query is ready for attachment of a LIMIT clause
    $query = $query . $LIMIT;
    //run query
}

Answer 2

My preferred way to do this when I have multiple parameters (some of which could be optional) is to create an object with setter functions. That way you can just do:

$objectname->setId($id);    
$objectname->setAll(true);

In your object you'd could also implement variables such as $current_question or $current_page , and $questions_per_page , and have a function called get_next_question_set() .

However, if you prefer to use functional programming for this and since PHP is loosely typed, you can also just do this:

$this->get_questions_incrementally(null, $id, $page_no=0, $items_per_page="ALL");

and then do a check to see if the value is a string equal to "ALL" or an integer.