what's this

[QashQesh]

<?php
class Database
{
// Singleton object. Leave $me alone.
private static $me;

public $DB;

public $type;

public $Host;

public $name;

public $Username;
public $Password;

public $onError; // Can be '', 'die', or 'redirect'
public $emailOnError;
public $queries;
public $result;

public $emailTo; // Where to send an error report
public $emailSubject;

public $errorUrl; // Where to redirect the user on error

// Singleton constructor
private function __construct()
{
$this->type = Config::get('dbType');
$this->name = Config::get('dbName');
$this->onError = Config::get('dbOnError');
$this->emailOnError = Config::get('dbEmailOnError');
$this->queries = array();
// MySQL specific stuff
if($this->type=='mysql') {
$this->writeHost = Config::get('dbHost');
$this->Username = Config::get('dbUsername');
$this->Password = Config::get('dbPassword');
$this->DB = false;
} else if($this->type=='sqlite') {
$this->DB = false;
} else {
die('Unsupported database type specified in class.config.php');
}
}

// Get Singleton object
public static function getDatabase()
{
if(is_null(self::$me))
self::$me = new Database();
return self::$me;
}
public function __wakeup()
{
$this->Connect();
}
public function __sleep()
{
if(is_object($this->DB)) {
$this->DB = null;
}
return array_keys(get_object_vars($this));
}

// Do we have a valid read/write database connection?
public function isConnected()
{
return is_object($this->DB);
}

// Are we using MySQL?
public function isMySQL()
{
if($this->type=='mysql') return true;
else return false;
}

// Do we have a valid database connection and have we selected
a database?
public function databaseSelected()
{
if(!$this->isConnected()) return false;
if($this->isMySQL()) {
$result = $this->readDB->query("SHOW TABLES FROM $this->name");
} else {
$this->Connect();
$result = $this->readDB->query("SELECT name FROM sqlite_master WHERE
type = 'table'");
}
return is_object($result);
}

public function Connect()
{
if($this->isMySQL()) {
$this->DB = new PDO("mysql:dbname=$this->name;host=$this->Host", $this-
>Username, $this->Password) or $this->notify();
if($this->DB === false) return false;
$this->DB->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
} else {
$this->DB = new PDO("sqlite:".DOC_ROOT.DS."db".DS."$this-
>name.sqlite") or $this->notify();
if($this->DB === false) return false;
$this->DB->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
}
return $this->isConnected();
}

public function query($sql, $args_to_prepare = null)
{
$sql = trim($sql);
if(!$this->isConnected()) $this->Connect();
$this->queries[] = $sql;
$this->result = $this->DB->prepare($sql) or $this->notify();
$this->result->execute($args_to_prepare);
return $this->result;
}

// Returns the number of rows.
// You can pass in nothing, a string, or a db result
public function numRows($arg = null)
{
$result = $this->resulter($arg);
return ($result !== false) ? $result->rowCount() : false;
}
// Returns the number of rows in the previously executed select
statement
public function rowCountResult()
{
if(!$this->isMySQL()) { // For SQLite only.
if( strtoupper( substr( $this->lastQuery(), 0, 6 ) ) == 'SELECT' )
{
// Do a SELECT COUNT(*) on the previously executed query
$res = $this->query('SELECT COUNT(*)' . substr( $this-
>lastQuery(), strpos( strtoupper( $this->lastQuery() ), 'FROM' ) ) )-
>fetch( PDO::FETCH_NUM );
return $res[0];
}
}
else return $this->result->rowCount(); // The last query
was not a SELECT query. Return the row count normally.
}
// Returns true / false if the result has one or more rows
public function hasRows($arg = null)
{
$result = $this->resulter($arg);
return is_object($result) && ($this->rowCountResult() >
0);
}

// Returns the number of rows affected by the previous WRITE
operation
public function affectedRows()
{
if(!$this->isConnected()) return false;
$ret = $this->result->rowCount();
return $ret;
}

// Returns the auto increment ID generated by the previous
insert statement
public function insertId()
{
if(!$this->isConnected()) return false;
$ret = ((is_null($this->DB->lastInsertId())) ? false : $this->DB-
>lastInsertId());
return $ret;
}

// Returns a single value.
// You can pass in nothing, a string, or a db result
public function getValue($arg = null)
{
$result = $this->resulter($arg);
return $this->hasRows($result) ? $result->fetchColumn() : false;
}

// Returns an array of the first value in each row.
// You can pass in nothing, a string, or a db result
public function getValues($arg = null)
{
$result = $this->resulter($arg);
if(!$this->hasRows($result)) return array();

$values = array();
$values = $result->fetchAll((PDO::FETCH_COLUMN|PDO::FETCH_GROUP), 0);
return $values;
}

// Returns the first row.
// You can pass in nothing, a string, or a db result
public function getRow($arg = null)
{
$result = $this->resulter($arg);
return $this->hasRows($result) ? $result->fetch(PDO::FETCH_ASSOC) :
false;
}

// Returns an array of all the rows.
// You can pass in nothing, a string, or a db result
public function getRows($arg = null)
{
$result = $this->resulter($arg);
if(!$this->hasRows($result)) return array();

$rows = array();
$rows = $result->fetchAll(PDO::FETCH_ASSOC);
return $rows;
}

// Same as escape()
public function quote($var)
{
return $this->escape($var);
}

// Escapes a value.
public function escape($var)
{
if(!$this->isConnected()) $this->Connect();
$ret = $this->DB->quote($var);
return $ret;
}

public function numQueries()
{
return count($this->queries);
}

public function lastQuery()
{
if($this->numQueries() > 0)
return $this->queries[$this->numQueries() - 1];
else
return false;
}

private function notify()
{
if($this->emailOnError === true)
{
$globals = print_r($GLOBALS, true);

$msg = '';
$msg .= "Url: " . full_url() . "\n";
$msg .= "Date: " . dater() . "\n";
$msg .= "Server: " . $_SERVER['SERVER_NAME'] . "\n";

//$msg .= "ReadDB Error:\n" . ((is_object($this-
>readDB)) ? mysqli_error($this->readDB) : (($___mysqli_res =
mysqli_connect_error()) ? $___mysqli_res : false)) . "\n\n";
//$msg .= "WriteDB Error:\n" . ((is_object($this-
>writeDB)) ? mysqli_error($this->writeDB) : (($___mysqli_res =
mysqli_connect_error()) ? $___mysqli_res : false)) . "\n\n";

ob_start();
debug_print_backtrace();
$trace = ob_get_contents();
ob_end_clean();

$msg .= $trace . "\n\n";

$msg .= $globals;

mail($this->emailTo, $this->emailSubject, $msg);
}

if($this->onError == 'die')
{
//echo "<p style='border:5px solid red;background-color:#fff;padding:
5px;'><strong>Read Database Error:</strong><br/>" . ((is_object($this-
>readDB)) ? mysqli_error($this->readDB) : (($___mysqli_res =
mysqli_connect_error()) ? $___mysqli_res : false)) . "</p>";
//echo "<p style='border:5px solid red;background-color:#fff;padding:
5px;'><strong>Write Database Error:</strong><br/>" . ((is_object($this-
>writeDB)) ? mysqli_error($this->writeDB) : (($___mysqli_res =
mysqli_connect_error()) ? $___mysqli_res : false)) . "</p>";
//$this->readDB->errorInfo();
//$this->writeDB->errorInfo();
//print_r($this->result->errorInfo());
echo '<br />';
echo "<p style='border:5px solid red;background-color:#fff;padding:
5px;'><strong>Last Query:</strong><br/>" . $this->lastQuery() . "</
p>";
echo "<pre>";
debug_print_backtrace();
echo "</pre>";
exit;
}

if($this->onError == 'redirect')
{
redirect($this->errorUrl);
}
}

// Takes nothing, a MySQL result, or a query string and
returns
// the correspsonding MySQL result resource or false if none
available.
private function resulter($arg = null)
{
if(is_null($arg) && is_object($this->result))
return $this->result;
elseif(is_object($arg))
return $arg;
elseif(is_string($arg))
{
$this->query($arg);
if(is_object($this->result))
return $this->result;
else
return false;
}
else
return false;
}
}
?>



Please give me some ditles about this code .. i feel different it :S

[Tyler Hall]

That looks like a branched version of our Database wrapper class that
operates on MySQL and SQLite. I'm afraid I can't offer much help since
I've never used it. Maybe the original author can?

Tyler

[Max Fierke]

You can use it in pretty much the same way as the original implementation. There were a few minor changes that broke some of the classes that depended on this, though. 

If you are using one of these classes, look into my PDO-friendly versions: https://github.com/maxfierke/arcanecms

If you're question is regarding the use of PHP Data Objects itself, read up on it here: http://www.phpro.org/tutorials/Introduction-to-PHP-PDO.html