I'm trying to make this code access a certain row in the database and pull "title" from it to update public $Title in the UserBlog class, but, it's not doing so.
The database connection is definitely working as it worked procedually, but OOP is messing it up.
$ID = $db->real_escape_string(strip_tags(stripslashes($_GET['ID']))); // Page ID
class UserBlog
{
public $Title;
public $BannerImage;
public $ID;
public function GenerateBlog() {
$FetchBlogDetails = mysqli_query($db, "SELECT * FROM UserBlogs WHERE ID = '$this->ID'");
$FBL = mysqli_fetch_object($FetchBlogDetails);
$this->Title = $FBL->Title;
}
public function FetchBlog() {
return $this->Title;
return $this->ID;
}
};
$GetBlog = new UserBlog();
$GetBlog->ID = $ID;
$GetBlog->GenerateBlog();
echo $GetBlog->Title;
echo $GetBlog->ID;
$db doesn't exist in the scope of your method. You could inject it when calling the method.
class UserBlog
{
public $Title;
public $BannerImage;
public $ID;
public function GenerateBlog($db) {
$FetchBlogDetails = mysqli_query($db, "SELECT * FROM UserBlogs WHERE ID = '$this->ID'");
$FBL = mysqli_fetch_object($FetchBlogDetails);
$this->Title = $FBL->Title;
}
//...
}
$GetBlog = new UserBlog();
$GetBlog->ID = $ID;
$GetBlog->GenerateBlog($db);
Related
how to properly work with sqlite in a class
I want to make a class that, in its methods, must refer to sqlite databases, depending on the parameters.
How to organize these connections correctly?
For example, something like this
class Text {
private $lang = 'EN';
private $id;
private $text;
public function __construct($lang) {
GLOBAL $db;
$this->lang = $lang;
$db = new SQLite3("./$this->lang/text.db");
}
public function dbSelectQuery($key) {
GLOBAL $db;
$stm = $db->query("SELECT * FROM TEXT WHERE KEY = '$key'");
$result = $stm->fetchArray(SQLITE3_ASSOC);
return $result['text'];
}
public function setText($key) {
$this->text = $this->dbSelectQuery($key);
}
}
You can use string interpolation "./{$lang}/text.db" to select the db by parameter.
i also removed all the globals. You can handle it with an other private variable and don´t need a GLOBAL
class Text {
private $lang = 'EN';
private $id;
private $text;
private $db;
public function __construct($lang) {
$this->lang = $lang;
$this->db = new SQLite3("./{$lang}/text.db");
}
public function dbSelectQuery($key) {
$stm = $this->db->query("SELECT * FROM TEXT WHERE KEY = '$key'");
$result = $stm->fetchArray(SQLITE3_ASSOC);
return $result['text'];
}
public function setText($key) {
$this->text = $this->dbSelectQuery($key);
}
}
im work with php and mysql, sometimes i need instantiate my php class in data access layer for return objects, load list etc... but sometimes I use the class constructor and others do not.
Can i create doble constructor in a class?
example:
class Student {
private $id;
private $name;
private $course;
function __construct() {
}
//get set id and name
function setCourse($course) {
$this->course = $course;
}
function getCourse() {
$this->course = $course;
}
}
class Course {
private $id;
private $description;
function __construct($id) {
this->id = $id;
}
//get set, id, description
}
In my access layer sometime I use the constructor in different ways
for example:
$result = $stmt->fetchAll();
$listStudent = new ArrayObject();
if($result != null) {
foreach($result as $row) {
$student = new Student();
$student->setId($row['id']);
$student->setName($row['name']);
$student->setCourse(new Course($row['idcourse'])); //this works
$listStudent ->append($sol);
}
}
But sometimes I need to use the constructor in another way, for example
$result = $stmt->fetchAll();
$listCourses = new ArrayObject();
if($result != null) {
foreach($result as $row) {
$course = new Course(); //but here not work, becouse Class course receives a id
$course->setId($row['idcourse']);
$course->setDescription($row['description']);
$listCourses->append($sol);
}
}
My english is very bad,
i hope you understand me
Use default arguments:
class Course {
private $id;
private $description;
function __construct($id = 0) {
this->id = $id;
}
// getters and setters for id and description
}
Now, you can use it like that:
$course = new Course(12); // works with argument
or:
$course = new Course(); // works without argument
$course->setId(12);
class Course {
private $id;
private $description;
public function __construct() {
// allocate your stuff
}
public static function constructWithID( $id ) {
$instance = new self();
//do your stuffs here
return $instance;
}
call like Course:: constructWithID(..id) when you have to pass id otherwise make object (new Course()).
I have a question about Dependency Injection in PHP.
I currently have this 3 classes:
Staff.php
<?php
class Staff
{
public function name($id)
{
return 'returning staff with id ' . $id;
}
}
Projects.php
<?php
class Projects
{
..... projects related functions
}
ProjectsManager.php
<?php
class ProjectsManager
{
private $staff = null;
private $projects = null;
public function __construct(Staff $staff, Projects $projects)
{
$this->staff = $staff;
$this->projects = $projects;
}
public function staff()
{
return $this->staff;
}
public function projects()
{
return $this->projects;
}
}
Those classes are instantiated like this:
$staff = new Staff;
$projects = new Projects;
$app = new ProjectsManager($staff, $projects);
echo $app->staff()->name(5);
The above is working, but what I would like to do is something like this:
$employee = $app->staff(5);
echo $employee->name();
echo $employee->position();
echo $employee->email();
How can I handle the dependency to achieve this?
You can simply add the set function in Staff class and call it in ProjectsManager:
<?php
class Staff
{
private $id = null;
public function name()
{
return 'returning staff with id ' . $this->id;
}
public function setId($id)
{
$this->id = $id;
}
}
class Projects
{
//..... projects related functions
}
class ProjectsManager
{
private $staff = null;
private $projects = null;
public function __construct(Staff $staff, Projects $projects)
{
$this->staff = $staff;
$this->projects = $projects;
}
public function staff($id = null)
{
$this->staff->setId($id);
return $this->staff;
}
public function projects($val = null)
{
return $this->projects;
}
}
$staff = new Staff;
$projects = new Projects;
$app = new ProjectsManager($staff, $projects);
$employee = $app->staff(5);
echo $employee->name();
$employee = $app->staff()->name(5);
//$app is the ProjectsManager
//$app->staff() returns it's Staff object
//staff()->name(5) Invokes the Staff object's name function
//Returns 'Returning staff with id 5'
echo $employee->name();
echo $employee->position();
echo $employee->email();
To avoid confusion, I would also suggest prefix some of those functions with get (eg. $app->getStaff()->getFromId(#))
Also, be sure to modify staff()->name(#) to actually return an object and not a string.
Assume the connection to the database and all references to tables and cells is correct... how could I get something like this working?
class User
{
private $_display;
private $_email;
public function __construct($username)
{
$fetch_user = mysql_query("SELECT * FROM `registered_users` WHERE `user_name`='$username'");
$fetch_user = mysql_fetch_array($fetch_user);
$this->_display = $fetch_user['user_display'];
$this->_email = $fetch_user['user_email'];
}
}
$person1 = new User('username');
echo "Information: " . print_r($person1, TRUE);
the problem is it returns nothing. Doesn't thrown an error or anything when debugged. Is it viable method though? :S
Here is roughly what I would do:
<?php
class User{
private $username;
private $data;
public function __construct($username){
$this->username = $username;
if($this->valid_username()){
$this->load();
}
}
private function load(){
// Let's pretend you have a global $db object.
global $db;
$this->data = $db->query('SELECT * FROM registered_users WHERE user_name=:username', array(':username'=>$this->username))->execute()->fetchAll();
}
public function save(){
// Save $this->data here.
}
/**
* PHP Magic Getter
*/
public function __get($var){
return $this->data[$var];
}
/**
* PHP Magic Setter
*/
public function __set($var, $val){
$this->data[$var] = $val;
}
private function valid_username(){
//check $this->username for validness.
}
// This lets you use the object as a string.
public function __toString(){
return $this->data['user_name'];
}
}
How to use:
<?php
$user = new User('donutdan');
echo $user->name; //will echo 'dan'
$user->name = 'bob';
$user->save(); // will save 'bob' to the database
I'm having problems with accessing variables from my classes...
class getuser {
public function __construct($id) {
$userquery = "SELECT * FROM users WHERE id = ".$id."";
$userresult = mysql_query($userquery);
$this->user = array();
$idx = 0;
while($user = mysql_fetch_object($userresult)){
$this->user[$idx] = $user;
++$idx;
}
}
}
I'm setting this class in a global 'classes' file, and later on I pass through a user id into the following script:
$u = new getuser($userid);
foreach($u->user as $user){
echo $user->username;
}
I'm hoping that this will give me the name of the user but it's not, where am I going wrong?!
Thanks
please define your users member as public in your class like this
class getuser {
public $user = null;
//...
}
in order to access a class property, you have to declare it public or implement getters and setters (second solution is preferable)
class A {
public $foo;
//class methods
}
$a = new A();
$a->foo = 'whatever';
with getters and setters, one per property
class B {
private $foo2;
public function getFoo2() {
return $this->foo2;
}
public function setFoo2($value) {
$this->foo2 = $value;
}
}
$b = new B();
$b->setFoo2('whatever');
echo $b->getFoo2();
in your example:
class getuser {
private $user;
public function __construct($id) {
$userquery = "SELECT * FROM users WHERE id = ".$id."";
$userresult = mysql_query($userquery);
$this->user = array();
$idx = 0;
while($user = mysql_fetch_object($userresult)){
$this->user[$idx] = $user;
++$idx;
}
}
/* returns the property value */
public function getUser() {
return $this->user;
}
/* sets the property value */
public function setUser($value) {
$this->user = $value;
}
}
$u = new getuser($userid);
$users_list = $u->getUser();
foreach($users_list as $user) {
echo $user->username;
}