Comment on my database wrapper.

bdm · 12-11-2007, 03:14 PM

I decided to write a wrapper class because we use MySQL and ODBC at work in most applications we write. So I thought it wouldn't be a bad idea if done right. So here's what I've got so far and it works, but I do believe it's missing flexibility.

Here is my hierarchy:

Code:

lib/
    config/
        databases.php
    Db/
        Adapter/
            Abstract,php
            Mysql.php
            Odbc.php
        DatabaseFactory.php

lib/config/databases.php

PHP Code:


			
$database = array(
    'mysql_host' => array(
        'host' => 'host',
        'username' => 'username',
        'password' => 'password',
        'defaultDb'=> 'default_db'
    ),
    'odbc_host' => array(
        'dsn' => 'dsn',
        'username' => 'username',
        'password' => 'password'
    )
);

lib/Db/DatabaseFactory.php

PHP Code:


			
class DatabaseFactory {
    public static function factory($adapter, $config) {
        if(!is_string($adapter) || empty($adapter)) {
            throw new Exception('adapter needs to be a string');
        }

        if(!is_array($config)) {
            throw new Exception('config needs to be an array');
        }
        
        $adapterNamespace = 'Db_Adapter';


        require_once 'Adapter/' . ucwords($adapter) . '.php';

        $adapterName = $adapterNamespace . '_' . $adapter;
        $dbAdapter = new $adapterName($config);
        
        return $dbAdapter;
    }
}

lib/Db/Adapter/Abstract.php

PHP Code:


			
abstract class Db_Adapter_Abstract {
    protected $_connection = null;
    protected $_results = null;
    protected $_searchResults = array();
    
    public function __construct($config) {
        $this->connect($config);
    }
    
    abstract protected function connect($config);

}

lib/Db/Adapter/Mysql.php

PHP Code:


			
include_once 'Abstract.php';

class Db_Adapter_Mysql extends Db_Adapter_Abstract {
    protected function connect($config) {
        try {
            $this->connection = mysql_connect(
                $config['host'], 
                $config['username'], 
                $config['password']
            );
    
            mysql_select_db($config['defaultDb']);
        } catch(Exception $e) {
            echo $e->getMessage();
        }
    }

    public function query($query) {
        $this->_results = mysql_query($query);

        return $this;
    }
    
    public function fetchAll() {
        while($row = mysql_fetch_assoc($this->_results)) {
            array_push($this->_searchResults, $row);
        }

        return $this->_searchResults;
    }

    public function getNumRows() {
        return (int) mysql_num_rows($this->_results);
    }
}

lib/Db/Adapter/Odbc.php

PHP Code:


			
include_once 'Abstract.php';

class Db_Adapter_Odbc extends Db_Adapter_Abstract {
    protected function connect($config) {
        try {
            $this->_connection = odbc_connect(
                $config['dsn'], 
                $config['username'], 
                $config['password']
            );    
        } catch(Exception $e) {
            echo 'e: ' . $e->getMessage();
        }
    }

    public function query($query, $params = array()) {
        if(!is_array($params) || empty($params)) {
            $this->_results = odbc_exec($this->_connection, $query);
        }
        
        if(is_array($params) && sizeof($params) > 0) {
            $stmt = odbc_prepare($this->_connection, $query) 
                or die(odbc_error());
            $this->_results = odbc_execute($stmt, $params)
                or die(odbc_error());
        }

        return $this;
    }
    
    public function fetchAll() {
        while($row = odbc_fetch_array($this->_results)) {
            array_push($this->_searchResults, $row);
        }

        return $this->_searchResults;
    }

    public function getNumRows() {
        return (int) odbc_num_rows($this->_results);
    }
}

Here is currently how you would use it:

PHP Code:


			
ini_set('display_errors', 'on');
error_reporting(E_ALL|E_STRICT);

include './config/databases.php';
include 'Db/DatabaseFactory.php';

$odbc = DatabaseFactory::factory('odbc', $database['odbc_host']);

echo '<pre>';
$q = $odbc->query('select * from foo');
print_r($q->fetchAll());
echo '</pre>';

$mysql = DatabaseFactory::factory('mysql', $database['mysql_host']);

echo '<pre>';
print_r($mysql->query('select * from bar')->fetchAll());
echo '</pre>';

One thing I was thinking about was making my results returned as an iterator list. Good idea?

Constructive criticism is more than welcomed.

Thank you.