php - Using database class with PDO -

the classic first liner - have seen similar questions on none me understand crossroads at.

a little background before code - not new php or pdo (though not expert either), complete newbie object oriented php , trying balance right of when use classes , when possibly overkill.

the answer i'm hoping in 2 parts. firstly, practice create wrapper database class when using pdo - connection, basic queries etc.

secondly, if not - there better ways speed query writing?

edit whilst questioning code below, question pdo wrapper class approach overall - class below larger this, there need/benefit?

see following code; note: class file called via spl_autoload_register() in config.php

class_database.php

class database {     private $conn;      public function __construct() {         $this->openconnection();     }      public function openconnection() {         try {             $this->conn = new pdo('mysql:host=' . db_server . '; dbname=' . db_name, db_user, db_pass);             $this->conn->setattribute(pdo::attr_errmode, pdo::errmode_exception);         } catch (pdoexception $e) {             echo 'there error connecting database, error: ' . $e->getmessage();             die();         }     }      public function getall($sql, array $params) {         $stmt = $this->conn->prepare($sql);         $stmt->execute($params);         return $stmt->fetch(pdo::fetch_assoc);     } } 

generic_file.php

require_once '../includes/config.php'; $dbh = new database();  $sql = ("select * users id = :id , username = :username"); $id = 1; $username = 'craig'; $params = array(':id' => $id,                 ':username' => $username); $row = $dbh->getall($sql, $params); var_dump($row); 

now, me seems totally pointless. using pdo alone, not wrapper class, query simple write. on top of - if want use different fetch methods - i'd have write more methods in class. also, have used simple function instantiate , return new pdo object, including file , assigning variable function return simple quick - again feel class method overkill.

also, code above, , doing in class, not losing benefit of 'preparing' statement have pass sql statement in each time, change variables same statement?

however, find lots of examples online, , on lynda.com using currently, of database wrapper classes. on top of - no expert, , therefore feel overkill may best practice , recommended, hence looking experts me out!

so...back question - there reason use such class when using pdo? if not, there dry method others use minimize lines of codes needed queries using pdo?

thanks in advance.

i had same question @ 1 time.

the benefit abstracting database away can assure connections made correctly , if ever need change type of database there 1 spot need change code for. makes easier check queries issued because know if echo , exit in class of queries able checked.

the way solved creating class constructer established connection , assigned private variable while setting table in database too. best way have few public functions create, retrieve, update, , delete. called crud. each function , first parameter array. creating takes array , creates prepared statement , executes it. similar thing others retrieve array being matched, update takes things ending in id , sets rest update id = provided, , delete deletes of keys = value in table.

edit: here delete function put in class. if 1 of parameter's values array prepare statement , cycle through it. 1 variable changing though. have pass array values of numerical indexes being array of want insert though not how set code.

public function delete($info) {     $dbh = $this->dbh;      if (isset($info['submit_action'])) unset($info['submit_action']);     $where = array();     foreach (array_keys($info) $name) {         $where[] .= "$name = :$name";     }     //echo "delete {$this->table_name} " . implode(" , ", $where) . ";"; exit;     $data = $dbh->prepare("delete {$this->table_name} " . implode(" , ", $where) . ";");     foreach ($info $name => $value) {         if ($array_value == $name) $data->bindparam(":$name", $array_info);         else $data->bindvalue(":$name", trim($value));     }      foreach ($info $name => $value) if (is_array($value)) { $array_value = $name; break; }     if (isset($array_value)) {          foreach ($info[$array_value] $array_info) {             try {                 $data->execute();             }             catch (pdoexception $e) {                 if (!is_null($this->error_msg))                     handle_error($this->error_msg, $e->getmessage());                 else                 handle_error("there problem removing {$this->subject}.", $e->getmessage());             }         }      } else {         try {             $data->execute();         }         catch (pdoexception $e) {             handle_error(/*public error msg - set anyway want*/, $e->getmessage());         }     }      // send success msg }