<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.2.4 or newer
 *
 * NOTICE OF LICENSE
 *
 * Licensed under the Open Software License version 3.0
 *
 * This source file is subject to the Open Software License (OSL 3.0) that is
 * bundled with this package in the files license.txt / license.rst.  It is
 * also available through the world wide web at this URL:
 * http://opensource.org/licenses/OSL-3.0
 * If you did not receive a copy of the license and are unable to obtain it
 * through the world wide web, please send an email to
 * licensing@ellislab.com so we can send you a copy immediately.
 *
 * @package		CodeIgniter
 * @author		EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
 * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
 * @link		http://codeigniter.com
 * @since		Version 3.0.0
 * @filesource
 */

/**
 * PDO Oracle Database Adapter Class
 *
 * Note: _DB is an extender class that the app controller
 * creates dynamically based on whether the query builder
 * class is being used or not.
 *
 * @package		CodeIgniter
 * @subpackage	Drivers
 * @category	Database
 * @author		EllisLab Dev Team
 * @link		http://codeigniter.com/user_guide/database/
 */
class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {

	public $subdriver = 'oci';

	/**
	 * The syntax to count rows is slightly different across different
	 * database engines, so this string appears in each driver and is
	 * used for the count_all() and count_all_results() functions.
	 */
	protected $_count_string = 'SELECT COUNT(1) AS ';
	protected $_random_keyword = ' ASC'; // Currently not supported

	protected $_reserved_identifiers = array('*', 'rownum');

	/**
	 * Constructor
	 *
	 * Builds the DSN if not already set.
	 *
	 * @param	array
	 * @return	void
	 */
	public function __construct($params)
	{
		parent::__construct($params);

		if (empty($this->dsn))
		{
			$this->dsn = 'oci:dbname=';

			// Oracle has a slightly different PDO DSN format (Easy Connect),
			// which also supports pre-defined DSNs.
			if (empty($this->hostname) && empty($this->port))
			{
				$this->dsn .= $this->database;
			}
			else
			{
				$this->dsn .= '//'.(empty($this->hostname) ? 'localhost' : $this->hostname)
					.(empty($this->port) ? '' : ':'.$this->port).'/';

				empty($this->database) OR $this->dsn .= $this->database;
			}

			empty($this->char_set) OR $this->dsn .= ';charset='.$this->char_set;
		}
		elseif ( ! empty($this->char_set) && strpos($this->dsn, 'charset=', 4) === FALSE)
		{
			$this->dsn .= ';charset='.$this->char_set;
		}
	}

	// --------------------------------------------------------------------

	/**
	 * Show table query
	 *
	 * Generates a platform-specific query string so that the table names can be fetched
	 *
	 * @param	bool
	 * @return	string
	 */
	protected function _list_tables($prefix_limit = FALSE)
	{
		$sql = 'SELECT "TABLE_NAME" FROM "ALL_TABLES"';

		if ($prefix_limit === TRUE && $this->dbprefix !== '')
		{
			return $sql.' WHERE "TABLE_NAME" LIKE \''.$this->escape_like_str($this->dbprefix)."%' "
				.sprintf($this->_like_escape_str, $this->_like_escape_chr);
		}

		return $sql;
	}

	// --------------------------------------------------------------------

	/**
	 * Show column query
	 *
	 * Generates a platform-specific query string so that the column names can be fetched
	 *
	 * @param	string	the table name
	 * @return	string
	 */
	protected function _list_columns($table = '')
	{
		return 'SELECT "COLUMN_NAME" FROM "all_tab_columns" WHERE "TABLE_NAME" = '.$this->escape($table);
	}

	// --------------------------------------------------------------------

	/**
	 * Field data query
	 *
	 * Generates a platform-specific query so that the column data can be retrieved
	 *
	 * @param	string	the table name
	 * @return	string
	 */
	protected function _field_data($table)
	{
		return 'SELECT * FROM '.$this->protect_identifiers($table).' WHERE rownum = 1';
	}

	// --------------------------------------------------------------------

	/**
	 * From Tables
	 *
	 * This function implicitly groups FROM tables so there is no confusion
	 * about operator precedence in harmony with SQL standards
	 *
	 * @param	array
	 * @return	string
	 */
	protected function _from_tables($tables)
	{
		return is_array($tables) ? implode(', ', $tables) : $tables;
	}

	// --------------------------------------------------------------------

	/**
	 * Insert_batch statement
	 *
	 * @param	string	the table name
	 * @param	array	the insert keys
	 * @param	array	the insert values
	 * @return 	string
	 */
	protected function _insert_batch($table, $keys, $values)
	{
		$keys = implode(', ', $keys);
		$sql = "INSERT ALL\n";

		for ($i = 0, $c = count($values); $i < $c; $i++)
		{
			$sql .= '	INTO '.$table.' ('.$keys.') VALUES '.$values[$i]."\n";
		}

		return $sql.'SELECT * FROM dual';
	}

	// --------------------------------------------------------------------

	/**
	 * Delete statement
	 *
	 * Generates a platform-specific delete string from the supplied data
	 *
	 * @param	string	the table name
	 * @param	array	the where clause
	 * @param	array	the like clause
	 * @param	string	the limit clause
	 * @return	string
	 */
	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
	{
		$conditions = array();

		empty($where) OR $conditions[] = implode(' ', $where);
		empty($like) OR $conditions[] = implode(' ', $like);
		empty($limit) OR $conditions[] = 'rownum <= '.$limit;

		return 'DELETE FROM '.$table.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '');
	}

	// --------------------------------------------------------------------

	/**
	 * Limit string
	 *
	 * Generates a platform-specific LIMIT clause
	 *
	 * @param	string	the sql query string
	 * @param	int	the number of rows to limit the query to
	 * @param	int	the offset value
	 * @return	string
	 */
	protected function _limit($sql, $limit, $offset)
	{
		return 'SELECT * FROM (SELECT inner_query.*, rownum rnum FROM ('.$sql.') inner_query WHERE rownum < '.($offset + $limit + 1).')'
			.($offset ? ' WHERE rnum >= '.($offset + 1): '');
	}

}

/* End of file pdo_oci_driver.php */
/* Location: ./system/database/drivers/pdo/subdrivers/pdo_oci_driver.php */