How to convert a string into a usable array

Question

Right now I'm currently attempting to make a MySQLi class to make typing code easier and so it looks cleaner and is more usable overall.

I'm attempting to write a function which will execute a query with a prepared statement. My dilemma is this:

  public function safeRead($query, $data, $params)
  {
    $stmt = $mysqli->prepare($query);
    $stmt->bind_param($params, $data);
    $stmt->execute();
    $result = $stmt->get_result();
    $check = $result->fetch_assoc();      
  }

I of course want to execute a query, as you can see. My problem lies with the $data variable. How can I/is it possible to pass data, as a string and possibly convert to an array or something usable so it can be used with bind_param ?

[explode](http://php.net/explode) converts a string into array. — fedorqui, Oct 07 '13 at 13:20
Although I quite familiar with binding problem in general, I have not a slightest idea, why do you need a string. — Your Common Sense, Oct 07 '13 at 13:21
It's not clear what you're asking. if it's about dealing with `IN` operator, then just check if passed parameter is an array with `is_array()` and then `join()` it into string — Alma Do, Oct 07 '13 at 13:22
looks like he want to pass the input as a string and convert it to an array for the bind_param function. if i understand him correct, he search for something like `$input_data = 'var1,var2,var3'; $as_array = explode(',', $input_data);` — MAQU, Oct 07 '13 at 13:24
Finally I got ot. **You don't need no string at all.** [Here you can see the code](http://stackoverflow.com/a/17874410/285587) — Your Common Sense, Oct 07 '13 at 13:26
Mushing parameters into a string is a bad idea (it will eventually become akin to rolling your own array type) and leads to zig-zag execution (callers will need to take data that is most likely already discrete and join them into a string just so your function can reverse the process). Just have them pass an array (use type-hinting). — webbiedave, Oct 07 '13 at 15:00

score -1 · Answer 1 · answered Oct 07 '13 at 13:34

bind_param prototype looks like this:

bool mysqli_stmt::bind_param ( string $types , mixed &$var1 [, mixed &$... ] )

so it accepts a string of types sssd, and a bunch of variables for those types

Assuming you are passing in the correct type of variables

$stmt->bind_param($params, $data);

A way to do this would be

   public function safeRead($query, $data, $params)
   {
    $stmt = $mysqli->prepare($query);
    $params = str_split( $params ); // Split the params 'sssd'
    foreach( $data as $k => $v ) {
        $stmnt->bind_param( $params[$k], $data[$k] );
    }
    $stmt->execute();
    $result = $stmt->get_result();
    $check = $result->fetch_assoc();      
  }

This is untested.

Edit

Since the second parameter of bind_param is passed by reference you MAY need to create an intermediate variable before binding, instead of binding the array item.

foreach( $data as $k => $v ) {
    $var_name = 'var'.$k;
    $$var_name = $v;
    $stmnt->bind_param( $params[$k], $$var_name );
}

but im not 100% sure.

How to convert a string into a usable array

1 Answers1