Why Does \'Call to a Member Function prepare() on a Non-Object\' Occur in PHP, and How Can I Fix It?

Call to Member Function prepare() on a Non-Object: PHP Help

Issue:

The error "Call to a member function prepare() on a non-object" occurs when attempting to call a method on an object that does not exist.

Cause:

The code snippet provided initializes the $DBH variable as a new MySQLi connection object, but fails to pass it as a parameter or declare it as a global variable within the selectInfo() function. As a result, the function cannot access the object and the error is thrown.

Solution:

To resolve this issue, consider the following options:

1. Use the Global Keyword:

   • function selectInfo($limit, $offset){
       global $DBH;
       $stmt = $DBH->prepare("SELECT * FROM information LIMIT ?,?");

2. Pass the Connection as a Parameter:

   • function selectInfo(MySQLi $DBH, $limit, $offset){
       $stmt = $DBH->prepare("SELECT * FROM information LIMIT ?,?");

3. Create a Function to Get the Database Connection:

   • function getDBH(){
       static $DBH = null;
       if (is_null($DBH)) {
           $DBH = new mysqli(...);
       }
       return $DBH;
     }

   function selectInfo($limit, $offset){

   $DBH = getDBH();
   $stmt = $DBH->prepare("SELECT * FROM information LIMIT ?,?");

   }

4. Create a Database Wrapper Class:

   • class Database {
       private $conn;
     
       public function __construct(){
           $this->conn = new mysqli(...);
       }
     
       public function selectInfo($limit, $offset){
           $stmt = $this->conn->prepare("SELECT * FROM information LIMIT ?,?");
       }

5. Use a Pre-Built Library or Framework:

   • Consider using a library or framework that handles database access, such as Doctrine ORM, ADODB, or a full-fledged framework like Zend.

The above is the detailed content of Why Does \'Call to a Member Function prepare() on a Non-Object\' Occur in PHP, and How Can I Fix It?. For more information, please follow other related articles on the PHP Chinese website!