Simple Model Class

code.php

<?php

class Model {
    
    protected function __construct() {
        parent::__construct();
    }
    
    public static function get_instance() {
        static $Inst = null;
        if( null === $Inst ) {
            $Inst = new self();
        }
        
        return $Inst;
    }
    
    public function save() {
        $vars = get_object_vars( $this );
        $data = [];
        
        foreach( $vars as $key => $val ) {
            if( in_array( $key, $this->excluded ) ||  'excluded' === $key || 'table' === $key ) continue;
            $data[$key]  = $val;
        }
        
        $sql = 'INSERT into ' . $this->table . ' (`' . implode( array_keys( $data ), '`, `' ) . '`) VALUES(\'' . implode( $data, '\', \'' ) . '\')';
        
        echo $sql;
    }
    
}

class People extends Model {
    public $table;
    public $name;
    public $age;
    public $job;
    public $excluded = [];
    
    protected function __construct() {
        $this->table = 'people';
        $this->name = 'Ash';
        $this->age = 32;
        $this->job = 'Developer';
        
        $this->excluded[] = 'age';
    }
    
    public static function get_instance() {
        static $Inst = null;
        if( null === $Inst ) {
            $Inst = new self();
        }
        
        return $Inst;
    }
}

$people = People::get_instance();
$people->save();
?>