Help using CI libraries from my own library

[eluser]Unknown[/eluser]
Hi every:
I have created a small library for parse SQL files and execute all queries. I need to use CI DB class from inside this class but I'm getting this error:

A PHP Error was encountered
Severity: Notice
Message: Undefined variable: ci
Filename: libraries/SQLParse.php
Line Number: 67

A PHP Error was encountered
Severity: Notice
Message: Trying to get property of non-object
Filename: libraries/SQLParse.php
Line Number: 67

This is the code I wrote:

Code:

<?php
if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class SQLParse {
  var $file;
  var $ci;

  function SQLParse() {
    $ci = & get_instance();
    $ci->load->database();
  }

  function setFile($file) {
    $this->file = $file;
  }

  function getFile() {
    return $this->file;
  }

  function startParsing() {
    $file = $this->getFile();
    // Getting the SQL file content
    $content = file_get_contents($file);
    // Processing the SQL file content
    $file_content = explode("\n",$content);
    $query = "";
    // Parsing the SQL file content
    foreach($file_content as $sql_line) {
      if(trim($sql_line) != "" && strpos($sql_line, "--") === false) {
        $query .= $sql_line;
        // Checking whether the line is a valid statement
        if(preg_match("/(.*);/", $sql_line)) {
          $query = substr($query, 0, strlen($query)-1);
          //Executing the parsed string, returns the error code in failure
          $result = $ci->db->query($query) or die(mysql_error());
          $query = "";
        }
      }
    } //End of foreach
    return true;
  } //End of function
} //End of class
?>

What I'm doing wrong?
Cheers and thanks in advance

[eluser]clip[/eluser]

Code:

$this->ci =& get_instance();

[eluser]Unknown[/eluser]
Thx a lot, it works now