how to bind in mysqli dynamically - php

Question

I'm in the middle of creating a custom Database Class to suit the requirements of the company i'm developing for. I currently have this:
class DBC {
protected $Link;
protected $Results;
public function __construct($Host = null,$User = null ,$Pass = null,$Database = null){
if ($Host === null OR $User === null OR $Pass === null OR $Database === null){
trigger_error("Incorrect Parameters Passed In The Database Link", E_USER_WARNING);
}
if (is_string($Host) AND is_string($User) AND is_string($Pass) AND is_string($Database)){
$this->Link = new mysqli($Host,$User,$Pass,$Database);
}else{
trigger_error("Expecting String(s), Array passed in one or more connection parameters",E_USER_ERROR);
}
}
public function Query ($Query,$Params){
$Query = $this->Link->prepare($Query);
$Query->bind_param();
}
}
Now.. I'm having a problem with how to sucessfully bind the parameters to the prepared statement.. For example, A Query will be submitted with this:
$DB = new DBC("Host","User","pass","database");
$DB->Query("SELECT * FROM Test WHERE Col=?",array("SearchCriteria"));
I've hit a block with figuring out how to bind_param and bind_result based on the results. A more clear insight is the normal procedure of MySQLi:
$SearchCriteria = "String";
$Query = $Database->prepare("SELECT * FROM Test WHERE Col=?");
$Query->bind_param('s',$SearchCriteria);
$Query->execute();
$Query->bind_results(/* Variables to match the column set */);
$Query->fetch();
$Query->close();
How can I bind the results and params to the prepared statement?

Answer 1

Below are copies of functions I use in a class that extends the mysqli class which do what you are asking.
function bind_placeholder_vars(&$stmt,$params,$debug=0) {
// Credit to: Dave Morgan
// Code ripped from: http://www.devmorgan.com/blog/2009/03/27/dydl-part-3-dynamic-binding-with-mysqli-php/
if ($params != null) {
$types = ''; //initial sting with types
foreach ($params as $param) { //for each element, determine type and add
if (is_int($param)) {
$types .= 'i'; //integer
} elseif (is_float($param)) {
$types .= 'd'; //double
} elseif (is_string($param)) {
$types .= 's'; //string
} else {
$types .= 'b'; //blob and unknown
}
}
$bind_names = array();
$bind_names[] = $types; //first param needed is the type string
// eg: 'issss'
for ($i=0; $i<count($params);$i++) { //go through incoming params and added em to array
$bind_name = 'bind' . $i; //give them an arbitrary name
$$bind_name = $params[$i]; //add the parameter to the variable variable
$bind_names[] = &$$bind_name; //now associate the variable as an element in an array
}
if ($debug) {
echo "\$bind_names:<br />\n";
var_dump($bind_names);
echo "<br />\n";
}
//error_log("better_mysqli has params ".print_r($bind_names, 1));
//call the function bind_param with dynamic params
call_user_func_array(array($stmt,'bind_param'),$bind_names);
return true;
}else{
return false;
}
}
function bind_result_array($stmt, &$row) {
// Credit to: Dave Morgan
// Code ripped from: http://www.devmorgan.com/blog/2009/03/27/dydl-part-3-dynamic-binding-with-mysqli-php/
$meta = $stmt->result_metadata();
while ($field = $meta->fetch_field()) {
$params[] = &$row[$field->name];
}
call_user_func_array(array($stmt, 'bind_result'), $params);
return true;
}
However, it sounds like you are doing something similar to what I have already done and have been using in many projects for a while now. Copy the contents of this pastebin (better_mysqli.php) into a new file and name it 'better_mysqli.php'
Then use it in your php program like so:
// include the class
include_once('better_mysqli.php');
// instantiate the object and open the database connection
$mysqli = new better_mysqli('yourserver.com', 'username', 'password', 'db_name');
if (mysqli_connect_errno()) {
die("Can't connect to MySQL Server. Errorcode: %s\n", mysqli_connect_error()), 'error');
}
// do a select query
$sth = $mysqli->select('select somecol, othercol from sometable where col1=? and col2=?', $row, array('col1_placeholder_value', 'col2_placeholder_value'));
while ($sth->fetch()) {
echo "somecol: ". $row['somecol'] ."<br />\n";
echo "othercol: ". $row['othercol'] ."<br />\n";
}
// the nice thing about this class is that the statement is only prepared once so if you use it again the already prepared statement is automatically used:
// do another select query with different placeholder values
$sth = $mysqli->select('select somecol, othercol from sometable where col1=? and col2=?', $row, array('other_col1_placeholder_value', 'other_col2_placeholder_value'));
while ($sth->fetch()) {
echo "somecol: ". $row['somecol'] ."<br />\n";
echo "othercol: ". $row['othercol'] ."<br />\n";
}
// the class supports the following methods: select, update, insert, and delete
// example delete:
$mysqli->delete('delete from sometable where col1=?', array('placeholder_val1'));