/**
* The constructor function which takes in an SQL query (or defaults to a select all from database) and calls the rewind() function to prep for looping
*
* @param string $sql (Optional) The SQL query used to retrieve product image rows from the database. If not used all rows will be selected from the database
* @return ISC_PRODUCT_IMAGE_ITERATOR
*/
public function __construct($sql='')
{
if(empty($sql)) {
$this->sql = ISC_PRODUCT_IMAGE::generateGetAllProductImagesFromDatabaseSql();
} else {
$this->sql = $sql;
}
$this->db = &$GLOBALS['ISC_CLASS_DB'];
$this->rewind();
}