creating pdo class in php - php

Question

I'm trying to create a simple php object to manage a mysql database through pdo. So far it connects to the database just fine and now when I try to insert a new row i get the follow error:
PHP Fatal error: Using $this when not in object context on line 37
line 37 is $STH = $this->DBH->prepare($sql);
i'm probably just using $this wrong. any help will be appreciated.
<?
class Database {
private $DBH;
//connects to the database
function __construct($host,$dbname,$user,$pass) {
try {
$this->DBH = new PDO("mysql:host=$host;dbname=$dbname", $user, $pass);
}
catch(PDOException $e) {
echo $e->getMessage();
}
}
//inserts into the database
//$tableName name of the table to insert the info into
//$items is a multidimensional array of array(column name, value)
public function insert($tableName,$items){
$values = array();
$sql = "INSERT INTO $tableName(";
$valuePlaceHolder = ''; // holds the question marks at the end of the PDO sql string
foreach($items as $item){
$sql .= $item[0] . ',';
array_push($values, $item[1]);
$valuePlaceHolder .= '?,';
}
// remove the last comma from the sql statement
$sql = substr($sql,0,-1);
$valuePlaceHolder = substr($valuePlaceHolder, 0, -1);
$sql .= ") values ($valuePlaceHolder)";
echo $sql;
$STH = $this->DBH->prepare($sql);
$STH->execute($values);
}
}
?>

Answer 1

read this:
http://www.php.net/manual/es/language.oop5.basic.php#88665
So that you can solve your problem:
....
// remove the last comma from the sql statement
$sql = substr($sql,0,-1);
$valuePlaceHolder = substr($valuePlaceHolder, 0, -1);
$sql .= ") values ($valuePlaceHolder)";
echo $sql;
$STH = Database::DBH;
$SHT = $SHT->prepare($sql);
$STH->execute($values);
.......