Convert array to variables dynamically and use them as function arguments

Question

I need to make a lot of mysql queries during data procession. As the actual code hardly changes, I would like to encapsulate it using a function. Such a function could be as follows:

// input: sql statement, binding parameters and paramter types
private prepared_statement($query, $params, $param_string) {

        // I use this peace of code over and over again

        $stmt = $this->db->prepare($query);
        if (!$stmt) {//TODO log
            echo "Error in prepared statement";
        }

        // problem
        $stmt->bind_param($param_string, $param1, $param2, ...);
        $stmt->execute();

        // problem
        $stmt->bind_result($);
        $stmt->fetch();
        $stmt->close(); 
        //...  
    }

The second function argument is an array that contains all binding parameters of the query to be made. I do not know how to pass them to the bind_param function, because it only accepts the binding parameters as single variables.

Is it possible to convert dynamically the param array to variables which then can be passed to bind_param?

Furthermore I am wondering how to bind the results best, as I don't know how many results are going to be returned. Actually it is the same problem as above.

can't you call bind_param in a loop, once for each variable (with $param_string[i], $param[i] as parameters for example...) ? — Random
– Random, Commented Sep 1, 2015 at 13:36
You can only loop over bind_param if you execute the statement in each iteration. This would cause a high overhead. — null
– null, Commented Sep 1, 2015 at 13:42
Jon, call_user_func_array seems tempting, but I guess you cannot pass a fixed string as the first paramter and convert the array to the 2nd, 3th,... parameter?! — null
– null, Commented Sep 1, 2015 at 13:47

Carlos Garcia · Accepted Answer · 2015-09-01 14:11:31Z

1

If you have a array like this:

$array = Array("name"=>"Jhon","surname"=>"Conor");

you can do:

extract($array);

and then use like this:

echo "Your name is " . $name . " and your surname is " . $surname;

answered Sep 1, 2015 at 14:11

Carlos Garcia

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1 Comment

null Over a year ago

This approach only works if I knew how many binding parameters exist. As each query look differently I cannot foresee the size of '$array'.

null · Accepted Answer · 2015-09-02 15:56:25Z

With the help of Jon's proposal to use call_user_func_array I managed to get the following solution:

private function prepared_statement($query, $params, $param_string) {

        $fetched_data = array();
        $binding_params[] = & $param_string;

        foreach($params as &$current_param) {
            $binding_params[] = & $current_param;
        }

        $stmt = $this->db->prepare($query);
        if (!$stmt) {
            //TODO log
            echo "Error in prepared statement";
        }

        call_user_func_array(array($stmt, "bind_param"), $binding_params);
        $stmt->execute();   
        $result = $stmt->get_result();
        while($row = $result->fetch_array(MYSQLI_ASSOC)) {
            foreach($row as $r) 
                array_push($fetched_data, $r);

        }

        $stmt->close(); 
        return $fetched_data;
    }

Tariq · Accepted Answer · 2015-09-01 14:12:50Z

0

You can use the '$' twice to get the variable:

foreach($my_arr AS $k => $v){
    $$k = $v;
}

answered Sep 1, 2015 at 14:12

Tariq

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