What is the best way to create Update Method using PHP OOP -

i have thinking of past hour, unable understand best way add update, insert feature using class in php.

i have employee table has around 5 columns, have created different properties in employees class.

now unable understand set these values, in __costructor(), in add_employees() method or other way..

if set them in __constructor() user must remember , follow same pattern in writing arguments followed in writing parameters.

i unable understand right way or should use different approach this.

i have searched on net, , found complex examples, people taking argument in form of array, separating it, add loop in , put database.

class employees(){      public $db;     public $conn;     public $emp_id;     public $first_name;     public $last_name;     public $gender;     public $added_by;      public function __construct(){         $this->db= new databaseconnection('localhost', 'root', '', 'employeesmanagement');         $this->conn= $this->db->connectdb();                 }      public function get_employees(){      }      public function add_employees(){      } 

i've written class before, things related database things. here class

/**  * class: database  *  * description: class deals database connection  * across website. if class needs use database  * has extends one.  *  * @author: andre ferraz  * @copyright: ^  * @version: 2.0  */ class database {     /**      * holds class object instance      *      * @var object      * @access: private      * @static      */     private static $_instace;     /**      * holds pdo object      *      * @var pdo      * @access: private      */     private $_pdo;     /**      * used keep track of how many columns      * has been found!      *      * @var int      * @access: private      */     private $_count;     /**      * holds data database      *      * @var array      * @access: private      */     private $_results = array();     /**      * description: instantiates pdo object      *      * @access: protected      */     protected function __construct()     {         $host = config::get("database:host");         $user = config::get("database:username");         $pass = config::get("database:password");         $dbna = config::get("database:dbname");         try         {             $this->_pdo = new pdo("mysql:dbname=".$dbna.";host=".$host.";", $user, $pass);         }         catch(pdoexception $e)         {             redirect::to(500);         }     }     /**      * description: gets data database      *      * @access: protected      * @return boolean      */     protected function get($table, $columns, $condition = null)     {         if($condition != null)         {             $query = $this->_pdo->prepare("select $columns $table $condition");             if($query->execute())             {                 $this->_count = $query->rowcount();                 if($this->_count > 0)                 {                     $this->_results = $query->fetchall();                     return true;                 }                 return false;             }         }         return false;         //@todo condition == null     }     /**      * description: similar function,      * instead checks if data exists without storing      * data.      *      * @access: protected      * @return boolean      */     protected function query($table, $columns, $condition = null)     {         if($condition != null)         {             $query = $this->_pdo->prepare("select $columns $table $condition");             if($query->execute())             {                 $this->_count = $query->rowcount();                 return(($this->_count > 0)? true : false);             }         }         return false;         //@todo condition == null     }     /**      * description: updates information on database      *      * @access: protected      */     protected function update($table, $cv = array(), $condition)     {         if($cv !=null)         {             $columns = '';             $x = 1;             foreach($cv $key => $value)             {                 $columns .= "$key='$value'";                 if($x < count($cv))                 {                     $columns .= ",";                 }                 $x++;             }             $query = $this->_pdo->prepare("update $table set $columns $condition");             if($query->execute())                 return true;             else                 return false;         }         return false;     }     /**      * description: inserts data database      *      * @access: protected      */     protected function insert($table, $cv = array())     {         if($cv !=null)         {             // join array elements string             $columns = implode(", ", array_keys($cv));             $values = '';             $x = 1;             // put array key values variables             foreach($cv $value)             {                 $values .= "'".$value."'";                 if($x < count($cv))                 {                     $values .= ', ';                 }                 $x++;             }             $query = $this->_pdo->prepare("insert $table ($columns) values({$values})");             // check execution successful             if($query->execute())                 return true;             else                 return false;         }         return false;     }     /**      * description: deletes data database      *      * @access: protected      */     protected function delete($table, $condition = null)     {         if($condition != null)         {             $query = $this->_pdo->prepare("delete $table $condition");             if($query->execute())                 return true;             else                 return false;         }         else         {             $query = $this->_pdo->prepare("delete $table");             if($query->execute())                 return true;             else                 return false;         }     }     protected function getresults()     {         return $this->_results;     }     /**      * description: singleton pattern, prevents multiple      * instantiations of same class.      *      * note: not needed. "show of"      *      * @access: public      * @static      * @return object      */     public static function instance()     {         if(isset(self::$_instace))             return self::$_instace;         else             self::$_instace = new self;     } } 

which other classes user class extend , use necessary function database data related user. have @ project. there bugs in few classes (which can't bothered fix @ point), database class working fine. don't mind if reference it.

visit github full project. github