Hallo,
ik probeer via object bewerkingen in een database te doen, maar ik krijg deze foutmelding terwijl ik wel een declaratie van de variabele doe, wat doe ik fout??
fout melding die ik krijg is:
Call to a member function delete() on a non-object in test.php on line 21
alvast bedankt!
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User Class
ik probeer via object bewerkingen in een database te doen, maar ik krijg deze foutmelding terwijl ik wel een declaratie van de variabele doe, wat doe ik fout??
fout melding die ik krijg is:
Call to a member function delete() on a non-object in test.php on line 21
alvast bedankt!
PHP:
<?php
require_once('../../includes/initialize.php');
if (!$session->is_logged_in()) { redirect_to("login.php"); }
?>
<?php include_layout_template('admin_header.php'); ?>
<?php
// $user = new User();
// $user->username = "johnsmith";
// $user->password = "abcd12345";
// $user->first_name = "John";
// $user->last_name = "Smith";
// $user->create();
// $user = User::find_by_id(2);
// $user->password = "12345wxyz";
// $user->save();
$user = User::find_by_id(2);
$user->delete();
echo $user->first_name . " was deleted";
?>
<?php include_layout_template('admin_footer.php'); ?>------------------------------------------------------
User Class
PHP:
<?php
// If it's going to need the database, then it's
// probably smart to require it before we start.
require_once(LIB_PATH.DS.'database.php');
class User extends DatabaseObject {
protected static $table_name = "users";
protected static $db_fields = array('id', 'username', 'password', 'first_name', 'last_name');
public $id;
public $username;
public $password;
public $first_name;
public $last_name;
public function full_name() {
if(isset($this->first_name) && isset($this->last_name)) {
return $this->first_name . " " . $this->last_name;
} else {
return "";
}
}
public static function authenticate($username="", $password="") {
global $database;
$username = $database->escape_value($username);
$password = $database->escape_value($password);
$sql = "SELECT * FROM users ";
$sql .= "WHERE username = '{$username}' ";
$sql .= "AND password = '{$password}' ";
$sql .= "LIMIT 1";
$result_array = self::find_by_sql($sql);
return !empty($result_array) ? array_shift($result_array) : false;
}
// Common Database Methods
public static function find_all() {
return self::find_by_sql("SELECT * FROM ".self::$table_name);
}
public static function find_by_id($id=0) {
$result_array = self::find_by_sql("SELECT * FROM ".self::$table_name." WHERE id={$id} LIMIT 1");
return !empty($result_array) ? array_shift($result_array) : false;
}
public static function find_by_sql($sql="") {
global $database;
$result_set = $database->query($sql);
$object_array = array();
while ($row = $database->fetch_array($result_set)) {
$object_array[] = self::instantiate($row);
}
return $object_array;
}
private static function instantiate($record) {
// Could check that $record exists and is an array
$object = new self;
// Simple, long-form approach:
// $object->id = $record['id'];
// $object->username = $record['username'];
// $object->password = $record['password'];
// $object->first_name = $record['first_name'];
// $object->last_name = $record['last_name'];
// More dynamic, short-form approach:
foreach($record as $attribute=>$value){
if($object->has_attribute($attribute)) {
$object->$attribute = $value;
}
}
return $object;
}
private function has_attribute($attribute) {
// get_object_vars returns an associative array with all attributes
// (incl. private ones!) as the keys and their current values as the value
$object_vars = $this->attributes();
// We don't care about the value, we just want to know if the key exists
// Will return true or false
return array_key_exists($attribute, $object_vars);
}
protected function attributes() {
$attributes = array();
foreach(self::$db_fields as $field) {
if(property_exists($this, field)) {
$attributes[$field] = $this->$field;
}
}
return $attributes;
}
protected function sanitized_attributes() {
global $database;
$clean_attributes = array();
foreach($this->attributes() as $key =>$value) {
$clean_attributes[$key] = $database->escape_value($value);
}
return $clean_attributes;
}
public function save() {
// A new record won't have an id yet.
return isset($this->id) ? $this->update() : $this->create();
}
public function create() {
global $database;
// Don't forget your SQL syntax and good habits:
// - INSERT INTO table (key, key) VALUES ('value', 'value')
// - single-quotes around all values
// - escape all values to prevent SQL injection
$attributes = $this->sanitized_attributes();
$sql = "INSERT INTO ".self::$table_name." (";
$sql .= join(", ", array_keys($attributes));
$sql .= ") VALUES ('";
$sql .= join("', '", array_keys($attributes));
$sql .= "')";
if($database->query($sql)) {
$this->id = $database->insert_id();
return true;
} else {
return false;
}
}
public function update() {
global $database;
// Don't forget your SQL syntax and good habits:
// - UPDATE table SET key='value', key='value' WHERE condition
// - single-quotes around all values
// - escape all values to prevent SQL injection
$attributes = $this->sanitized_attributes();
$attribute_pairs = array();
foreach($attributes as $key => $value) {
$attribute_pairs[] = "{$key}='{$value}'";
}
$sql = "UPDATE ".self::$table_name." SET ";
$sql .= join(", ", $attribute_pairs);
$sql .= " WHERE id=". $database->escape_value($this->id);
$database->query($sql);
return ($database->affected_rows() == 1) ? true : false;
}
public function delete() {
global $database;
$sql = "DELETE FROM ".self::$table_name." ";
$sql .= "WHERE id=". $database->escape_value($this->id);
$sql .= " LIMIT 1";
$database->query($sql);
return ($database->affected_rows() == 1) ? true : false;
}
}
?>
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