• I need to bind values for insert()
• Use try/catch for error handling

• I need to bind values for insert()
• Use try/catch for error handling
• Password hashing (did not use it to make example simpler)

Im trying to get familiare with (i dont even know how this is called) database handling

Can you guys point out my errors and what i should change?
I want to learn new methods, i just dont want to learn it the wrong way.

PS. i do realize these things below yet i wanted to make the code more clear
 

• i need to bind values for insert
   
• use try/catch for error handling
  _db = new PDO('mysql:host=localhost;dbname=mvc;', 'root', ''); $this->_db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); $this->_db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC); } public function select($arg) { $this->_sql .= "SELECT {$arg}"; return $this; } public function from($arg) { $this->_sql .= " FROM {$arg}"; return $this; } public function insert($arg) { $this->_sql .= "INSERT INTO {$arg}"; return $this; } public function columns($arg) { $this->_sql .= " ({$arg})"; return $this; } public function values($arg) { $this->_sql .= " VALUES ({$arg})"; return $this; } public function execute($data = null) { $this->_sth = $this->_db->prepare($this->_sql); $this->_sth->execute($data); $this->_sql = null; return $this; } public function fetch() { return $this->_sth->fetchAll(); } public function getSql() { return $this->_sql; } } $query = new Query; // inserts into database $query->insert('users') ->columns('`username`,`password`') ->values('"test","tester"') ->execute(); // returns array of users $query->select('username') ->from('users') ->execute() ->fetch() ?>

I'm trying to get familiar with database handling. Can you point out my errors and what I should change?

I want to learn new methods, but just don't want to learn it the wrong way.

I do realize these things below, yet I wanted to make the code more clear:

• I need to bind values for insert()
• Use try/catch for error handling

<?php

class Query 
{
    private $_sql;
    private $_sth;
    private $_db;

    public function __construct() 
    {
        $this->_db = new PDO('mysql:host=localhost;dbname=mvc;', 'root', '');
        $this->_db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $this->_db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
    }

    public function select($arg)
    {
        $this->_sql .= "SELECT {$arg}";
        return $this;
    }

    public function from($arg)
    {
        $this->_sql .= " FROM {$arg}";
        return $this;
    } 

    public function insert($arg)
    {
        $this->_sql .= "INSERT INTO {$arg}";
        return $this;        
    }

    public function columns($arg)
    {
        $this->_sql .= " ({$arg})";
        return $this;            
    }

    public function values($arg)
    {
        $this->_sql .= " VALUES ({$arg})";
        return $this;            
    }

    public function execute($data = null)
    {
        $this->_sth = $this->_db->prepare($this->_sql);
        $this->_sth->execute($data);
        $this->_sql = null;
        return $this;
    }

    public function fetch()
    {
        return $this->_sth->fetchAll();
    }

    public function getSql()
    {
        return $this->_sql;
    }
}


$query = new Query;

// inserts into database
$query->insert('users')
        ->columns('`username`,`password`')
        ->values('"test","tester"')
        ->execute();

// returns array of users
$query->select('username')
        ->from('users')
        ->execute()
        ->fetch()

?>