Database class

Database.php

<?php

/**
 * Database class
 *
 * @author	Mark James
 * @package
 */

/**

To setup:

$config = array();
$config['database_host'] = 'localhost';
$config['database_name'] = 'mydatabase';
$config['database_user'] = 'local';
$config['database_password'] = '';
Database::GetInstance( $config );

To use in your controller:

$db = Database::GetInstance();
$db->run('SELECT * FROM `table` WHERE fieldname=:fieldname', array('fieldname'=>'Hello World'));

*/
class Database extends PDO {

	/**
	 * Number of queries executed
	 *
	 * @var int
	 */
	public $queryCount;

	/**
	 * Statements
	 *
	 * @var array
	 */
	protected $_statements = array();

	/**
	 * Fetch mode
	 *
	 * @var mixed 
	 */
	protected $_fetchMode;

	/**
	 * Instances
	 *
	 * @var array
	 */
	public static $Instances = array();

	/**
	 * Get database instance
	 * 
	 * @param Config $config Config
	 * @return Database
	 */
	public static function GetInstance( $config=null ) {

		if( $config==null ) {
			return current(self::$Instances);
		} else {

			if( isset($config['database_socket']) && $config['database_socket'] ) {
				$dsn = 'mysql:unix_socket='.$config['database_socket'].';dbname='.$config['database_name'];
			} else {
				$dsn = 'mysql:host='.$config['database_host'].';dbname='.$config['database_name'];
			}

			$username = $config['database_user'];
			$password = $config['database_password'];

			$id = "$dsn;$username;$password;";
			if( !array_key_exists( $id, self::$Instances ) ) {
				self::$Instances[$id] = new Database( $config );
			}
			return self::$Instances[$id];
		}
	}

	/**
	 * Constructor for Database
	 * 
	 */
	public function __construct( $config, $configOverrides=null ) {

		// Get DB info from config
		$this->config = $config;
		$this->_fetchMode = PDO::FETCH_ASSOC;
		$this->queryCount = 0;

		if( $configOverrides === null ) {

			if( isset($config['database_socket']) && $config['database_socket'] ) {
				$dsn = 'mysql:unix_socket='.$config['database_socket'].';dbname='.$config['database_name'];
			} else {
				$dsn = 'mysql:host='.$config['database_host'].';dbname='.$config['database_name'];
			}

			$username = $config['database_user'];
			$password = $config['database_password'];
		} else {

			if( isset($config['database_socket']) && $config['database_socket'] ) {
				$dsn = 'mysql:unix_socket='.array_get('database_socket',$configOverrides,$config['database_socket']).';dbname='.array_get('database_name',$configOverrides,$config['database_name']);
			} else {
				$dsn = 'mysql:host='.array_get('database_host',$configOverrides,$config['database_host']).';dbname='.array_get('database_name',$configOverrides,$config['database_name']);
			}

			$username = array_get('database_user',$configOverrides,$config['database_user']);
			$password = array_get('database_password',$configOverrides,$config['database_password']);
		}

		// Create PDO instance
		PDO::__construct( $dsn, $username, $password );
		$this->setAttribute( PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true );
		$this->setAttribute( PDO::ATTR_STATEMENT_CLASS, array(array_get('database_statement_class',$config,'Database_Statement'), array(null,null)));
		$this->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
		$this->setAttribute( PDO::ATTR_EMULATE_PREPARES, true );
	}

	/**
	 * Run
	 * 
	 * @param String $query Query
	 * @param String $params Params
	 * @return Database_Statement
	 */
	public function run( $query, $params=null ) {

		// If an array has been passed in, then perform them all in
		// a transaction with rollback
		if( is_array( $query ) ) {

			$statements = array();

			foreach( $query as $q ) {
				
				// We already have this statement prepared
				if( isset( $this->_statements[$q] ) ) {
					$statements[] = $this->_statements[$q];
					continue;
				}
				// Prepare statement
				$statement = $this->prepare( $q );
				$statement->setFetchMode( $this->_fetch_mode );
				$statements[] = $statement;
				$this->_statements[$q] = $statement;

			}
			// Statements are prepared, try running them with the params
			$stmt = null;
			try {
				$this->beginTransaction();
				foreach( $this->_statements[$query_key] as $stmt ) {
					$stmt->execute( $params );
					$this->queryCount++;
				}

				$this->commit();
				return $this->_statements[$query_key];
			} catch( PDOException $e ) {
				$this->rollBack();
				if( null !== $stmt ) {
					$error = $stmt->errorInfo();
					throw new Exception( implode(', ', $error) );
				}
			}
		
		// Query is just a single query
		} else {
			// Prepare query
			if( !isset($this->_statements[$query]) ) {
				$this->_statements[$query] = $this->prepare( $query );
			}
			// Run query. Return statement if successful, FALSE otherwise.
			if( $this->_statements[$query]->execute( $params ) || '00000' === $this->_statements[$query]->errorCode() ) {
				$this->queryCount++;
				return $this->_statements[$query];
			} else {
				$error = $this->_statements[$query]->errorInfo();
				throw new Exception( implode(', ', $error) );
			}
		}

	}

}
?>