PHP OOP CRUD

Object Oriented Programming

Objects
Classes
"$this"
You probably know more
about it by now...

Object

"An Object is an individual instance of the data structure defined by a class."

Class

"Classes are the blueprints of objects."
Classes have attributes :: $this->name
Classes have functions :: $this->getUserName()

Simple PHP OOP code

<?php
class A {
    public $foo = 1;
}

$a = new A;
$b = $a;
$b->foo = 2;
$c = new A;

echo $a->foo."\n";
echo $b->foo."\n";
echo $c->foo."\n";

Classes

Basic class

<?php
class User {
    protected $name;

    public function _construct() {
        //We do not use any constructor, just here for showing usage
    }

    //Getters
    public function getName() {
        return $this->name;
    }

    //Setters
    public function setName($name) {
        $this->name = $name;
    }
}

//Create new instance/ object
$a = new User;
//Set the name "Michiel"
$a->setName("Michiel");

//Show the name thru getName variable
echo $a->getName()."\n";
//Show name by just passing the attribute
echo $a->name;

public, private, protected, static?

Public - The item (variable/ function) can be used on the object outside the class (always)
Protected - The item can not be called outside the class
Private - The item can only be used within the object and will not be inherited/ extended to child-classes
Static - The item can be used without 'calling/creating' a class instance first (in PHP use :: to use static functions)

Class User

<?php
class User {
    public $public = 'Public';
    protected $protected = 'Protected';
    private $private = 'Private';

    function printUser() {
        echo $this->public."\n";
        echo $this->protected."\n";
        echo $this->private."\n";
    }
}

$obj = new User();
echo $obj->public."\n";
echo $obj->protected."\n";
echo $obj->private."\n";
$obj->printUser();

Extends/ implements

For now, don't use the second (used by interfaces)
Extend does what the name says, it extends the previous class, all the attributes and functions are available in the child class
parent - child solutions

Class Doctor

<?php
Class Doctor extends User {
    public $public = 'Public2';

    public function printDocter() {
        echo $this->public."\n";
        echo $this->protected."\n";
        echo $this->private."\n";
    }

}

$obj2 = new Doctor();
echo $obj2->public."\n";
echo $obj2->protected."\n";
echo $obj2->private."\n";
$obj2->printDoctor();

$obj2->printUser();

<?php
class User {
    public $public = 'Public';
    protected $protected = 'Protected';
    private $private = 'Private';

    public function printUser() {
        echo $this->public."\n";
        echo $this->protected."\n";
        echo $this->private."\n";
    }
}

Database

Create a Settings class

<?php

/**
 * Class DatabaseSettings basic class to store mysql-settings.
 */
class DatabaseSettings
{
    var $settings;

    /**
     * @return array
     */
    function getSettings()
    {
        $settings = [];
        // Database variables
        // Host name
        $settings['dbhost'] = 'localhost';
        // Database name
        $settings['dbname'] = 'phpoopcrud';
        // Username
        $settings['dbusername'] = 'phpoopcrud';
        // Password
        $settings['dbpassword'] = 'phpoopcrud';

        return $settings;
    }
}

Create a Database class

<?php

require_once( 'DatabaseSettings.php' );

class Database extends DatabaseSettings
{
    var $classQuery;
    var $link;

    var $errno = '';
    var $error = '';

    /**
     * Database constructor.
     */
    function __construct()
    {
        // Load settings from parent class
        $settings = DatabaseSettings::getSettings();

        // Get the main settings from the array we just loaded
        $host = $settings['dbhost'];
        $name = $settings['dbname'];
        $user = $settings['dbusername'];
        $pass = $settings['dbpassword'];

        // Connect to the database
        $this->link = new mysqli( $host , $user , $pass , $name );

        //Set the charset...
        mysqli_set_charset($this->link, 'utf8mb4');
    }

    /**
     * Database destructor
     */
    function __destruct() {
        $this->close();
    }

    // Executes a database query
    function query( $query )
    {
        $this->classQuery = $query;
        if ($value = $this->link->query( $query )) {
            return $value;
        } else {
            printf("Error: %s\n", $this->link->error);
        }
    }

    //Escape data
    function escapeString( $query )
    {
        return $this->link->real_escape_string( $query );
    }

    // Get the data return int result
    function numRows( $result )
    {
        return $result->num_rows;
    }

    //Get the last inserted ID
    function lastInsertedID()
    {
        return $this->link->insert_id;
    }

    // Get query using assoc method
    function fetchAssoc( $result )
    {
        return $result->fetch_assoc();
    }

    // Gets array of query results
    function fetchArray( $result , $resultType = MYSQLI_ASSOC )
    {
        return $result->fetch_array( $resultType );
    }

    // Fetches all result rows as an associative array, a numeric array, or both
    function fetchAll( $result , $resultType = MYSQLI_ASSOC )
    {
        return $result->fetch_all( $resultType );
    }

    // Get a result row as an enumerated array
    function fetchRow( $result )
    {
        return $result->fetch_row();
    }

    // Free all MySQL result memory
    function freeResult( $result )
    {
        $this->link->free_result( $result );
    }

    //Closes the database connection
    function close()
    {
        $this->link->close();
    }

    //Return the current error number and message
    function sql_error()
    {
        if( empty( $error ) )
        {
            $errno = $this->link->errno;
            $error = $this->link->error;
        }

        return $errno . ' : ' . $error;
    }
}

Use the code in the class

<?php

require_once('../database/Database.php');

/**
 * Class Model
 * Basic usage, extend this file to any database-table/ model
 */
class Model
{
    static $DB;
    static $table;

    function __construct($table) {
        $this->setTable($table);
        $this->setDB(new Database());
    }

    function setTable($table) {
        static::$table = $table;
        return;
    }

    function setDB($DB) {
        static::$DB = $DB;
        return;
    }

    static protected function getTable() {
        return static::$table;
    }

    static protected function getDB() {
        return static::$DB;
    }

    public function className() {
        return get_class($this);
    }

    public function save() {
        if (empty($this->id)) {
            $this->id = $this->saveNew();
        } else {
            $id = $this->id;
            $this->saveExisting($id);
        }
    }

    public function saveExisting($id) {
        $where = " WHERE id = ".$id;
        $updateQry = "id = $id";

        $modelColumns = $this->getAllColumnInformation();
        foreach ($modelColumns AS $column) {
            $c = $column[0];
            if ($c != 'id') {
                $cols[] = $c;
                if (strpos(strtolower($column[1]), 'int') !== false) {
                    $updateQry .= ", " . $c . " = " . $this->$c;
                } else {
                    $updateQry .= ", " . $c . " = '" . $this->getDB()->escapeString(htmlentities($this->$c)) . "'";
                }
            }
        }

        $qry = "UPDATE ".$this->getTable()." SET ".$updateQry.$where;
        $this->getDB()->query($qry);

        return true;
    }

    public function saveNew() {
        $modelColumns = $this->getAllColumnInformation();
        $cols = [];
        $values = [];
        foreach ($modelColumns AS $column) {
            $c = $column[0];
            if ($c != 'id') {
                $cols[] = $c;
                if (strpos(strtolower($column[1]), 'int') !== false) {
                    $values[] = $this->$c;
                } else {
                    $value = static::$DB->escapeString($this->$c);
                    $values[] = "'$value'";
                }
            }
        }

        $qry = "INSERT INTO ".$this->getTable()." (".implode(',', $cols).") VALUES (".implode(',', $values).");";

        static::$DB->query($qry);
        return $this->getDB()->lastInsertedID();
    }

    public static function all() {
        $model = static::childClass();
        $db = new Database();
        $allData = $db->query('SELECT id FROM '.static::$table)->fetch_all();
        $retData = [];
        foreach ($allData AS $obj)
            $retData[] = $model::find($obj[0]);

        return $retData;
    }

    public static function find($id) {
        $obj = static::childClass();
        $model = new $obj(static::getTable());

        $keys = $model->getColumns();
        $cols = [];
        foreach ($keys AS $k)
            $cols[] = $k;

        $theUser = static::$DB->query('SELECT * FROM '.static::$table.' WHERE id = '.$id)->fetch_row();

        foreach ($cols AS $key => $value)
            $model->$value = $theUser[$key];

        return $model;
    }

    public static function whereOne($array) {
        $obj = static::where($array);
        if (!empty($obj))
            return $obj[0];

        return null;
    }

    public static function where($array) {
        $model = static::childClass();
        $where = ' WHERE 1 = 1';
        foreach ($array AS $a)
            $where .= " AND $a[0] $a[1] $a[2]";

        $db = new Database();
        $qry = "SELECT id FROM ".static::$table.$where;
        $allData = $db->query($qry)->fetch_all();

        $retData = [];
        foreach ($allData AS $obj)
            $retData[] = $model::find($obj[0]);

        return $retData;
    }

    public static function getAllColumnInformation() {
        $db = new Database();
        $cols = $db->query("SHOW columns FROM ".static::$table.";")->fetch_all();
        $retData = [];
        foreach ($cols AS $c)
            $retData[] = $c;

        return $retData;
    }

    public static function getColumns() {
        $db = new Database();
        $cols = $db->query("SHOW columns FROM ".static::$table.";")->fetch_all();
        $retData = [];
        foreach ($cols AS $c)
            $retData[] = $c[0];

        return $retData;
    }

    public function delete() {
        $qry = 'DELETE FROM '.$this->getTable().' WHERE id = '.$this->id;

        return $this->getDB()->query($qry);
    }

    public static function childClass() {
        return get_called_class();
    }

    public function hasOne($model, $primary_key, $foreign_key) {
        return $model::whereOne([[$foreign_key,'=', $this->$primary_key]]);
    }

    public function BelongsTo($model, $primary_key, $foreign_key) {
        return $model::whereOne([[$primary_key, '=', $this->$foreign_key]]);
    }

    public function hasMany($model, $primary_key, $foreign_key) {
        return $model::where([[$foreign_key,'=', $this->$primary_key]]);
    }
}

Use it in a Model

<?php

require_once ('Model.php');

class User extends Model
{
    static $table = 'users';

    /**
     * Class constructor
     */
    function __construct() {
        parent::__construct(static::$table);
    }

}

Insert data

Rule one - never trust user input
Rule two - Really never trust user input

Script/ HTML tags removal

mysqli_real_escape_string - makes it SQL safe
Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
htmlentities - makes it HTML proof
Convert all applicable characters to HTML entities
(If you need HTML codes from DB, either store them or use PHP function html_entity_decode

Tip van flip

Webserver zonder XAMP

php -S localhost:8080
--
PHP 7.2.13 Development Server started at Tue Apr  9 11:58:05 2019
Listening on http://localhost:8080
Document root is /sites/php-oop-crud/public
Press Ctrl-C to quit.

PHP OOP CRUD

By CodePamoja

PHP OOP CRUD

Simple presentation for PHP OOP Crud system

CodePamoja

CodePamoja means "Code Together" in Swahili. We are a group of passionate developers in The Netherlands and Kenya working together in virtual teams, transferring the latest software development skills to each other.

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PHP OOP CRUD

Object Oriented Programming

Object

Class

Simple PHP OOP code

Classes

Basic class

public, private, protected, static?

Class User

Extends/ implements

Class Doctor

Database

Create a Settings class

Create a Database class

Use the code in the class

Use it in a Model

Insert data

Script/ HTML tags removal

Tip van flip

Webserver zonder XAMP

PHP OOP CRUD

More from CodePamoja