<?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 1.0
 * @filesource
 */

/**
 * ODBC 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_odbc_driver extends CI_DB {

	public $dbdriver = 'odbc';

	// the character used to excape - not necessary for ODBC
	protected $_escape_char = '';

	// clause and character used for LIKE escape sequences
	protected $_like_escape_str = " {escape '%s'} ";
	protected $_like_escape_chr = '!';

	/**
	 * 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(*) AS ';
	protected $_random_keyword;

	public function __construct($params)
	{
		parent::__construct($params);

		$this->_random_keyword = ' RND('.time().')'; // database specific random keyword

		// Legacy support for DSN in the hostname field
		if ($this->dsn == '')
		{
			$this->dsn = $this->hostname;
		}
	}

	/**
	 * Non-persistent database connection
	 *
	 * @return	resource
	 */
	public function db_connect()
	{
		return @odbc_connect($this->dsn, $this->username, $this->password);
	}

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

	/**
	 * Persistent database connection
	 *
	 * @return	resource
	 */
	public function db_pconnect()
	{
		return @odbc_pconnect($this->dsn, $this->username, $this->password);
	}

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

	/**
	 * Execute the query
	 *
	 * @param	string	an SQL query
	 * @return	resource
	 */
	protected function _execute($sql)
	{
		return @odbc_exec($this->conn_id, $sql);
	}

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

	/**
	 * Begin Transaction
	 *
	 * @return	bool
	 */
	public function trans_begin($test_mode = FALSE)
	{
		if ( ! $this->trans_enabled)
		{
			return TRUE;
		}

		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ($this->_trans_depth > 0)
		{
			return TRUE;
		}

		// Reset the transaction failure flag.
		// If the $test_mode flag is set to TRUE transactions will be rolled back
		// even if the queries produce a successful result.
		$this->_trans_failure = ($test_mode === TRUE) ? TRUE : FALSE;

		return odbc_autocommit($this->conn_id, FALSE);
	}

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

	/**
	 * Commit Transaction
	 *
	 * @return	bool
	 */
	public function trans_commit()
	{
		if ( ! $this->trans_enabled)
		{
			return TRUE;
		}

		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ($this->_trans_depth > 0)
		{
			return TRUE;
		}

		$ret = odbc_commit($this->conn_id);
		odbc_autocommit($this->conn_id, TRUE);
		return $ret;
	}

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

	/**
	 * Rollback Transaction
	 *
	 * @return	bool
	 */
	public function trans_rollback()
	{
		if ( ! $this->trans_enabled)
		{
			return TRUE;
		}

		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ($this->_trans_depth > 0)
		{
			return TRUE;
		}

		$ret = odbc_rollback($this->conn_id);
		odbc_autocommit($this->conn_id, TRUE);
		return $ret;
	}

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

	/**
	 * Escape String
	 *
	 * @param	string
	 * @param	bool	whether or not the string will be used in a LIKE condition
	 * @return	string
	 */
	public function escape_str($str, $like = FALSE)
	{
		if (is_array($str))
		{
			foreach ($str as $key => $val)
			{
				$str[$key] = $this->escape_str($val, $like);
			}

			return $str;
		}

		// ODBC doesn't require escaping
		$str = remove_invisible_characters($str);

		// escape LIKE condition wildcards
		if ($like === TRUE)
		{
			return str_replace(array($this->_like_escape_chr, '%', '_'),
						array($this->_like_escape_chr.$this->_like_escape_chr, $this->_like_escape_chr.'%', $this->_like_escape_chr.'_'),
						$str);
		}

		return $str;
	}

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

	/**
	 * Affected Rows
	 *
	 * @return	int
	 */
	public function affected_rows()
	{
		return @odbc_num_rows($this->conn_id);
	}

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

	/**
	 * Insert ID
	 *
	 * @return	bool
	 */
	public function insert_id()
	{
		return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
	}

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

	/**
	 * "Count All" query
	 *
	 * Generates a platform-specific query string that counts all records in
	 * the specified database
	 *
	 * @param	string
	 * @return	string
	 */
	public function count_all($table = '')
	{
		if ($table == '')
		{
			return 0;
		}

		$query = $this->query($this->_count_string . $this->protect_identifiers('numrows') . " FROM " . $this->protect_identifiers($table, TRUE, NULL, FALSE));

		if ($query->num_rows() == 0)
		{
			return 0;
		}

		$row = $query->row();
		$this->_reset_select();
		return (int) $row->numrows;
	}

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

	/**
	 * 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)
	{
		$sql = "SHOW TABLES FROM `".$this->database."`";

		if ($prefix_limit !== FALSE AND $this->dbprefix != '')
		{
			//$sql .= " LIKE '".$this->escape_like_str($this->dbprefix)."%' ".sprintf($this->_like_escape_str, $this->_like_escape_chr);
			return FALSE; // not currently supported
		}

		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($table = '')
	{
		return "SHOW COLUMNS FROM ".$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($table)
	{
		return "SELECT TOP 1 FROM ".$table;
	}

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

	/**
	 * Error
	 *
	 * Returns an array containing code and message of the last
	 * database error that has occured.
	 *
	 * @return	array
	 */
	public function error()
	{
		return array('code' => odbc_error($this->conn_id), 'message' => odbc_errormsg($this->conn_id));
	}

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

	/**
	 * 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($tables)
	{
		if ( ! is_array($tables))
		{
			$tables = array($tables);
		}

		return '('.implode(', ', $tables).')';
	}

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

	/**
	 * Truncate statement
	 *
	 * Generates a platform-specific truncate string from the supplied data
	 *
	 * If the database does not support the truncate() command,
	 * then this method maps to 'DELETE FROM table'
	 *
	 * @param	string	the table name
	 * @return	string
	 */
	protected function _truncate($table)
	{
		return 'DELETE FROM '.$table;
	}

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

	/**
	 * 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)
	{
		// Does ODBC doesn't use the LIMIT clause?
		return $sql;
	}

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

	/**
	 * Close DB Connection
	 *
	 * @return	void
	 */
	protected function _close()
	{
		@odbc_close($this->conn_id);
	}

}

/* End of file odbc_driver.php */
/* Location: ./system/database/drivers/odbc/odbc_driver.php */