system/database/drivers/oci8/oci8_driver.php - code-igniter-v3-giggi - Gitiles

 <?php  if (!defined('BASEPATH')) exit('No direct script access allowed');
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP 4.3.2 or newer
  *
  * @package	 	CodeIgniter
  * @author	  	ExpressionEngine Dev Team
  * @copyright   Copyright (c) 2006, EllisLab, Inc.
  * @license	 	http://codeigniter.com/user_guide/license.html
  * @link		http://codeigniter.com
  * @since	   	Version 1.0
  * @filesource
  */

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

 /**
  * oci8 Database Adapter Class
  *
  * Note: _DB is an extender class that the app controller
  * creates dynamically based on whether the active record
  * class is being used or not.
  *
  * @package	 	CodeIgniter
  * @subpackage  Drivers
  * @category	Database
  * @author	  	ExpressionEngine Dev Team
  * @link		http://codeigniter.com/user_guide/database/
  */

 /**
  * oci8 Database Adapter Class
  *
  * This is a modification of the DB_driver class to
  * permit access to oracle databases
  *
  * NOTE: this uses the PHP 4 oci methods
  *
  * @author	  Kelly McArdle
  *
  */

 class CI_DB_oci8_driver extends CI_DB {

 	/**
 	 * 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.
 	 */
 	var $_count_string = "SELECT COUNT(1) AS ";
 	var $_random_keyword = ' ASC'; // not currently supported

 	// Set "auto commit" by default
 	var $_commit = OCI_COMMIT_ON_SUCCESS;

 	// need to track statement id and cursor id
 	var $stmt_id;
 	var $curs_id;

 	// if we use a limit, we will add a field that will
 	// throw off num_fields later
 	var $limit_used;

 	/**
 	 * Non-persistent database connection
 	 *
 	 * @access  private called by the base class
 	 * @return  resource
 	 */
 	function db_connect()
 	{
 		return @ocilogon($this->username, $this->password, $this->hostname);
 	}

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

 	/**
 	 * Persistent database connection
 	 *
 	 * @access  private called by the base class
 	 * @return  resource
 	 */
 	function db_pconnect()
 	{
 		return @ociplogon($this->username, $this->password, $this->hostname);
 	}

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

 	/**
 	 * Select the database
 	 *
 	 * @access  private called by the base class
 	 * @return  resource
 	 */
 	function db_select()
 	{
 		return TRUE;
 	}

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

 	/**
 	 * Set client character set
 	 *
 	 * @access	public
 	 * @param	string
 	 * @param	string
 	 * @return	resource
 	 */
 	function db_set_charset($charset, $collation)
 	{
 		// TODO - add support if needed
 		return TRUE;
 	}

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

 	/**
 	 * Version number query string
 	 *
 	 * @access  public
 	 * @return  string
 	 */
 	function _version()
 	{
 		return ociserverversion($this->conn_id);
 	}

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

 	/**
 	 * Execute the query
 	 *
 	 * @access  private called by the base class
 	 * @param   string  an SQL query
 	 * @return  resource
 	 */
 	function _execute($sql)
 	{
 		// oracle must parse the query before it is run. All of the actions with
 		// the query are based on the statement id returned by ociparse
 		$this->_set_stmt_id($sql);
 		ocisetprefetch($this->stmt_id, 1000);
 		return @ociexecute($this->stmt_id, $this->_commit);
 	}

 	/**
 	 * Generate a statement ID
 	 *
 	 * @access  private
 	 * @param   string  an SQL query
 	 * @return  none
 	 */
 	function _set_stmt_id($sql)
 	{
 		if (! is_resource($this->stmt_id))
 		{
 			$this->stmt_id = ociparse($this->conn_id, $this->_prep_query($sql));
 		}
 	}

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

 	/**
 	 * Prep the query
 	 *
 	 * If needed, each database adapter can prep the query string
 	 *
 	 * @access  private called by execute()
 	 * @param   string  an SQL query
 	 * @return  string
 	 */
 	function _prep_query($sql)
 	{
 		return $sql;
 	}

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

 	/**
 	 * getCursor.  Returns a cursor from the datbase
 	 *
 	 * @access  public
 	 * @return  cursor id
 	 */
 	function get_cursor()
 	{
 		$this->curs_id = ocinewcursor($this->conn_id);
 		return $this->curs_id;
 	}

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

 	/**
 	 * Stored Procedure.  Executes a stored procedure
 	 *
 	 * @access  public
 	 * @param   package	 package stored procedure is in
 	 * @param   procedure   stored procedure to execute
 	 * @param   params	  array of parameters
 	 * @return  array
 	 *
 	 * params array keys
 	 *
 	 * KEY	  OPTIONAL	NOTES
 	 * name	 no		  the name of the parameter should be in :<param_name> format
 	 * value	no		  the value of the parameter.  If this is an OUT or IN OUT parameter,
 	 *					  this should be a reference to a variable
 	 * type	 yes		 the type of the parameter
 	 * length   yes		 the max size of the parameter
 	 */
 	function stored_procedure($package, $procedure, $params)
 	{
 		if ($package == '' OR $procedure == '' OR ! is_array($params))
 		{
 			if ($this->db_debug)
 			{
 				log_message('error', 'Invalid query: '.$package.'.'.$procedure);
 				return $this->display_error('db_invalid_query');
 			}
 			return FALSE;
 		}

 		// build the query string
 		$sql = "begin $package.$procedure(";

 		$have_cursor = FALSE;
 		foreach($params as $param)
 		{
 			$sql .= $param['name'] . ",";

 			if (array_key_exists('type', $param) && ($param['type'] == OCI_B_CURSOR))
 			{
 				$have_cursor = TRUE;
 			}
 		}
 		$sql = trim($sql, ",") . "); end;";

 		$this->stmt_id = FALSE;
 		$this->_set_stmt_id($sql);
 		$this->_bind_params($params);
 		$this->query($sql, FALSE, $have_cursor);
 	}

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

 	/**
 	 * Bind parameters
 	 *
 	 * @access  private
 	 * @return  none
 	 */
 	function _bind_params($params)
 	{
 		if (! is_array($params) OR ! is_resource($this->stmt_id))
 		{
 			return;
 		}

 		foreach ($params as $param)
 		{
  			foreach (array('name', 'value', 'type', 'length') as $val)
 			{
 				if (! isset($param[$val]))
 				{
 					$param[$val] = '';
 				}
 			}

 			ocibindbyname($this->stmt_id, $param['name'], $param['value'], $param['length'], $param['type']);
 		}
 	}

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

 	/**
 	 * Begin Transaction
 	 *
 	 * @access	public
 	 * @return	bool
 	 */
 	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;

 		$this->_commit = OCI_DEFAULT;
 		return TRUE;
 	}

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

 	/**
 	 * Commit Transaction
 	 *
 	 * @access	public
 	 * @return	bool
 	 */
 	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;
 		}

 		$ret = OCIcommit($this->conn_id);
 		$this->_commit = OCI_COMMIT_ON_SUCCESS;
 		return $ret;
 	}

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

 	/**
 	 * Rollback Transaction
 	 *
 	 * @access	public
 	 * @return	bool
 	 */
 	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;
 		}

 		$ret = OCIrollback($this->conn_id);
 		$this->_commit = OCI_COMMIT_ON_SUCCESS;
 		return $ret;
 	}

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

 	/**
 	 * Escape String
 	 *
 	 * @access  public
 	 * @param   string
 	 * @return  string
 	 */
 	function escape_str($str)
 	{
 		return $str;
 	}

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

 	/**
 	 * Affected Rows
 	 *
 	 * @access  public
 	 * @return  integer
 	 */
 	function affected_rows()
 	{
 		return @ocirowcount($this->stmt_id);
 	}

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

 	/**
 	 * Insert ID
 	 *
 	 * @access  public
 	 * @return  integer
 	 */
 	function insert_id()
 	{
 		// not supported in oracle
 		return $this->display_error('db_unsupported_function');
 	}

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

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

 		$query = $this->query($this->_count_string . $this->_protect_identifiers('numrows'). " FROM " . $this->_protect_identifiers($this->dbprefix.$table));

 		if ($query == FALSE)
 			{
 			return 0;
 			}

 		$row = $query->row();
 		return $row->NUMROWS;
 	}

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

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

 		if ($prefix_limit !== FALSE AND $this->dbprefix != '')
 		{
 			$sql .= " WHERE TABLE_NAME LIKE '".$this->dbprefix."%'";
 		}

 		return $sql;
 	}

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

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

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

 	/**
 	 * Field data query
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
 	 * @access  public
 	 * @param   string  the table name
 	 * @return  object
 	 */
 	function _field_data($table)
 	{
 		return "SELECT * FROM ".$this->_escape_table($table)." where rownum = 1";
 	}

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

 	/**
 	 * The error message string
 	 *
 	 * @access  private
 	 * @return  string
 	 */
 	function _error_message()
 	{
 		$error = ocierror($this->conn_id);
 		return $error['message'];
 	}

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

 	/**
 	 * The error message number
 	 *
 	 * @access  private
 	 * @return  integer
 	 */
 	function _error_number()
 	{
 		$error = ocierror($this->conn_id);
 		return $error['code'];
 	}

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

 	/**
 	 * Escape Table Name
 	 *
 	 * This function adds backticks if the table name has a period
 	 * in it. Some DBs will get cranky unless periods are escaped
 	 *
 	 * @access  private
 	 * @param   string  the table name
 	 * @return  string
 	 */
 	function _escape_table($table)
 	{
 		if (strpos($table, '.') !== FALSE)
 		{
 			$table = '"' . str_replace('.', '"."', $table) . '"';
 		}

 		return $table;
 	}

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

 	/**
 	 * Protect Identifiers
 	 *
 	 * This function adds backticks if appropriate based on db type
 	 *
 	 * @access	private
 	 * @param	mixed	the item to escape
 	 * @param	boolean	only affect the first word
 	 * @return	mixed	the item with backticks
 	 */
 	function _protect_identifiers($item, $first_word_only = FALSE)
 	{
 		if (is_array($item))
 		{
 			$escaped_array = array();

 			foreach($item as $k=>$v)
 			{
 				$escaped_array[$this->_protect_identifiers($k)] = $this->_protect_identifiers($v, $first_word_only);
 			}

 			return $escaped_array;
 		}

 		// This function may get "item1 item2" as a string, and so
 		// we may need ""item1" "item2"" and not ""item1 item2""
 		if (ctype_alnum($item) === FALSE)
 		{
 			if (strpos($item, '.') !== FALSE)
 			{
 				$aliased_tables = implode(".",$this->ar_aliased_tables).'.';
 				$table_name =  substr($item, 0, strpos($item, '.')+1);
 				$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;
 			}

 			// This function may get "field >= 1", and need it to return ""field" >= 1"
 			$lbound = ($first_word_only === TRUE) ? '' : '|\s|\(';

 			$item = preg_replace('/(^'.$lbound.')([\w\d\-\_]+?)(\s|\)|$)/iS', '$1"$2"$3', $item);
 		}
 		else
 		{
 			return "\"{$item}\"";
 		}

 		$exceptions = array('AS', '/', '-', '%', '+', '*', 'OR', 'IS');

 		foreach ($exceptions as $exception)
 		{

 			if (stristr($item, " \"{$exception}\" ") !== FALSE)
 			{
 				$item = preg_replace('/ "('.preg_quote($exception).')" /i', ' $1 ', $item);
 			}
 		}
 		return $item;
 	}

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

 	/**
 	 * From Tables
 	 *
 	 * This function implicitly groups FROM tables so there is no confusion
 	 * about operator precedence in harmony with SQL standards
 	 *
 	 * @access	public
 	 * @param	type
 	 * @return	type
 	 */
 	function _from_tables($tables)
 	{
 		if (! is_array($tables))
 		{
 			$tables = array($tables);
 		}

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

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

 	/**
 	 * Insert statement
 	 *
 	 * Generates a platform-specific insert string from the supplied data
 	 *
 	 * @access  public
 	 * @param   string  the table name
 	 * @param   array   the insert keys
 	 * @param   array   the insert values
 	 * @return  string
 	 */
 	function _insert($table, $keys, $values)
 	{
 	return "INSERT INTO ".$this->_escape_table($table)." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
 	}

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

 	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @access	public
 	 * @param	string	the table name
 	 * @param	array	the update data
 	 * @param	array	the where clause
 	 * @param	array	the orderby clause
 	 * @param	array	the limit clause
 	 * @return	string
 	 */
 	function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
 	{
 		foreach($values as $key => $val)
 		{
 			$valstr[] = $key." = ".$val;
 		}

 		$limit = (!$limit) ? '' : ' LIMIT '.$limit;

 		$orderby = (count($orderby) >= 1)?' ORDER BY '.implode(", ", $orderby):'';

 		$sql = "UPDATE ".$this->_escape_table($table)." SET ".implode(', ', $valstr);
 		$sql .= ($where != '' AND count($where) >=1) ? " WHERE ".implode(" ", $where) : '';
 		$sql .= $orderby.$limit;

 		return $sql;
 	}

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

 	/**
 	 * Truncate statement
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 * If the database does not support the truncate() command
 	 * This function maps to "DELETE FROM table"
 	 *
 	 * @access	public
 	 * @param	string	the table name
 	 * @return	string
 	 */
 	function _truncate($table)
 	{
 		return "TRUNCATE TABLE ".$this->_escape_table($table);
 	}

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

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

 		if (count($where) > 0 || count($like) > 0)
 		{
 			$conditions = "\nWHERE ";
 			$conditions .= implode("\n", $this->ar_where);

 			if (count($where) > 0 && count($like) > 0)
 			{
 				$conditions .= " AND ";
 			}
 			$conditions .= implode("\n", $like);
 		}

 		$limit = (!$limit) ? '' : ' LIMIT '.$limit;

 		return "DELETE FROM ".$table.$conditions.$limit;
 	}

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

 	/**
 	 * Limit string
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
 	 * @access  public
 	 * @param   string  the sql query string
 	 * @param   integer the number of rows to limit the query to
 	 * @param   integer the offset value
 	 * @return  string
 	 */
 	function _limit($sql, $limit, $offset)
 	{
 		$limit = $offset + $limit;
 		$newsql = "SELECT * FROM (select inner_query.*, rownum rnum FROM ($sql) inner_query WHERE rownum < $limit)";

 		if ($offset != 0)
 		{
 			$newsql .= " WHERE rnum >= $offset";
 		}

 		// remember that we used limits
 		$this->limit_used = TRUE;

 		return $newsql;
 	}

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

 	/**
 	 * Close DB Connection
 	 *
 	 * @access  public
 	 * @param   resource
 	 * @return  void
 	 */
 	function _close($conn_id)
 	{
 		@ocilogoff($conn_id);
 	}


 }
	<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
	/**
	* CodeIgniter
	*
	* An open source application development framework for PHP 4.3.2 or newer
	*
	* @package CodeIgniter
	* @author ExpressionEngine Dev Team
	* @copyright Copyright (c) 2006, EllisLab, Inc.
	* @license http://codeigniter.com/user_guide/license.html
	* @link http://codeigniter.com
	* @since Version 1.0
	* @filesource
	*/

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

	/**
	* oci8 Database Adapter Class
	*
	* Note: _DB is an extender class that the app controller
	* creates dynamically based on whether the active record
	* class is being used or not.
	*
	* @package CodeIgniter
	* @subpackage Drivers
	* @category Database
	* @author ExpressionEngine Dev Team
	* @link http://codeigniter.com/user_guide/database/
	*/

	/**
	* oci8 Database Adapter Class
	*
	* This is a modification of the DB_driver class to
	* permit access to oracle databases
	*
	* NOTE: this uses the PHP 4 oci methods
	*
	* @author Kelly McArdle
	*
	*/

	class CI_DB_oci8_driver extends CI_DB {

	/**
	* 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.
	*/
	var $_count_string = "SELECT COUNT(1) AS ";
	var $_random_keyword = ' ASC'; // not currently supported

	// Set "auto commit" by default
	var $_commit = OCI_COMMIT_ON_SUCCESS;

	// need to track statement id and cursor id
	var $stmt_id;
	var $curs_id;

	// if we use a limit, we will add a field that will
	// throw off num_fields later
	var $limit_used;

	/**
	* Non-persistent database connection
	*
	* @access private called by the base class
	* @return resource
	*/
	function db_connect()
	{
	return @ocilogon($this->username, $this->password, $this->hostname);
	}

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

	/**
	* Persistent database connection
	*
	* @access private called by the base class
	* @return resource
	*/
	function db_pconnect()
	{
	return @ociplogon($this->username, $this->password, $this->hostname);
	}

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

	/**
	* Select the database
	*
	* @access private called by the base class
	* @return resource
	*/
	function db_select()
	{
	return TRUE;
	}

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

	/**
	* Set client character set
	*
	* @access public
	* @param string
	* @param string
	* @return resource
	*/
	function db_set_charset($charset, $collation)
	{
	// TODO - add support if needed
	return TRUE;
	}

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

	/**
	* Version number query string
	*
	* @access public
	* @return string
	*/
	function _version()
	{
	return ociserverversion($this->conn_id);
	}

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

	/**
	* Execute the query
	*
	* @access private called by the base class
	* @param string an SQL query
	* @return resource
	*/
	function _execute($sql)
	{
	// oracle must parse the query before it is run. All of the actions with
	// the query are based on the statement id returned by ociparse
	$this->_set_stmt_id($sql);
	ocisetprefetch($this->stmt_id, 1000);
	return @ociexecute($this->stmt_id, $this->_commit);
	}

	/**
	* Generate a statement ID
	*
	* @access private
	* @param string an SQL query
	* @return none
	*/
	function _set_stmt_id($sql)
	{
	if (! is_resource($this->stmt_id))
	{
	$this->stmt_id = ociparse($this->conn_id, $this->_prep_query($sql));
	}
	}

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

	/**
	* Prep the query
	*
	* If needed, each database adapter can prep the query string
	*
	* @access private called by execute()
	* @param string an SQL query
	* @return string
	*/
	function _prep_query($sql)
	{
	return $sql;
	}

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

	/**
	* getCursor. Returns a cursor from the datbase
	*
	* @access public
	* @return cursor id
	*/
	function get_cursor()
	{
	$this->curs_id = ocinewcursor($this->conn_id);
	return $this->curs_id;
	}

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

	/**
	* Stored Procedure. Executes a stored procedure
	*
	* @access public
	* @param package package stored procedure is in
	* @param procedure stored procedure to execute
	* @param params array of parameters
	* @return array
	*
	* params array keys
	*
	* KEY OPTIONAL NOTES
	* name no the name of the parameter should be in :<param_name> format
	* value no the value of the parameter. If this is an OUT or IN OUT parameter,
	* this should be a reference to a variable
	* type yes the type of the parameter
	* length yes the max size of the parameter
	*/
	function stored_procedure($package, $procedure, $params)
	{
	if ($package == '' OR $procedure == '' OR ! is_array($params))
	{
	if ($this->db_debug)
	{
	log_message('error', 'Invalid query: '.$package.'.'.$procedure);
	return $this->display_error('db_invalid_query');
	}
	return FALSE;
	}

	// build the query string
	$sql = "begin $package.$procedure(";

	$have_cursor = FALSE;
	foreach($params as $param)
	{
	$sql .= $param['name'] . ",";

	if (array_key_exists('type', $param) && ($param['type'] == OCI_B_CURSOR))
	{
	$have_cursor = TRUE;
	}
	}
	$sql = trim($sql, ",") . "); end;";

	$this->stmt_id = FALSE;
	$this->_set_stmt_id($sql);
	$this->_bind_params($params);
	$this->query($sql, FALSE, $have_cursor);
	}

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

	/**
	* Bind parameters
	*
	* @access private
	* @return none
	*/
	function _bind_params($params)
	{
	if (! is_array($params) OR ! is_resource($this->stmt_id))
	{
	return;
	}

	foreach ($params as $param)
	{
	foreach (array('name', 'value', 'type', 'length') as $val)
	{
	if (! isset($param[$val]))
	{
	$param[$val] = '';
	}
	}

	ocibindbyname($this->stmt_id, $param['name'], $param['value'], $param['length'], $param['type']);
	}
	}

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

	/**
	* Begin Transaction
	*
	* @access public
	* @return bool
	*/
	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;

	$this->_commit = OCI_DEFAULT;
	return TRUE;
	}

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

	/**
	* Commit Transaction
	*
	* @access public
	* @return bool
	*/
	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;
	}

	$ret = OCIcommit($this->conn_id);
	$this->_commit = OCI_COMMIT_ON_SUCCESS;
	return $ret;
	}

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

	/**
	* Rollback Transaction
	*
	* @access public
	* @return bool
	*/
	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;
	}

	$ret = OCIrollback($this->conn_id);
	$this->_commit = OCI_COMMIT_ON_SUCCESS;
	return $ret;
	}

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

	/**
	* Escape String
	*
	* @access public
	* @param string
	* @return string
	*/
	function escape_str($str)
	{
	return $str;
	}

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

	/**
	* Affected Rows
	*
	* @access public
	* @return integer
	*/
	function affected_rows()
	{
	return @ocirowcount($this->stmt_id);
	}

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

	/**
	* Insert ID
	*
	* @access public
	* @return integer
	*/
	function insert_id()
	{
	// not supported in oracle
	return $this->display_error('db_unsupported_function');
	}

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

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

	$query = $this->query($this->_count_string . $this->_protect_identifiers('numrows'). " FROM " . $this->_protect_identifiers($this->dbprefix.$table));

	if ($query == FALSE)
	{
	return 0;
	}

	$row = $query->row();
	return $row->NUMROWS;
	}

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

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

	if ($prefix_limit !== FALSE AND $this->dbprefix != '')
	{
	$sql .= " WHERE TABLE_NAME LIKE '".$this->dbprefix."%'";
	}

	return $sql;
	}

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

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

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

	/**
	* Field data query
	*
	* Generates a platform-specific query so that the column data can be retrieved
	*
	* @access public
	* @param string the table name
	* @return object
	*/
	function _field_data($table)
	{
	return "SELECT * FROM ".$this->_escape_table($table)." where rownum = 1";
	}

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

	/**
	* The error message string
	*
	* @access private
	* @return string
	*/
	function _error_message()
	{
	$error = ocierror($this->conn_id);
	return $error['message'];
	}

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

	/**
	* The error message number
	*
	* @access private
	* @return integer
	*/
	function _error_number()
	{
	$error = ocierror($this->conn_id);
	return $error['code'];
	}

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

	/**
	* Escape Table Name
	*
	* This function adds backticks if the table name has a period
	* in it. Some DBs will get cranky unless periods are escaped
	*
	* @access private
	* @param string the table name
	* @return string
	*/
	function _escape_table($table)
	{
	if (strpos($table, '.') !== FALSE)
	{
	$table = '"' . str_replace('.', '"."', $table) . '"';
	}

	return $table;
	}

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

	/**
	* Protect Identifiers
	*
	* This function adds backticks if appropriate based on db type
	*
	* @access private
	* @param mixed the item to escape
	* @param boolean only affect the first word
	* @return mixed the item with backticks
	*/
	function _protect_identifiers($item, $first_word_only = FALSE)
	{
	if (is_array($item))
	{
	$escaped_array = array();

	foreach($item as $k=>$v)
	{
	$escaped_array[$this->_protect_identifiers($k)] = $this->_protect_identifiers($v, $first_word_only);
	}

	return $escaped_array;
	}

	// This function may get "item1 item2" as a string, and so
	// we may need ""item1" "item2"" and not ""item1 item2""
	if (ctype_alnum($item) === FALSE)
	{
	if (strpos($item, '.') !== FALSE)
	{
	$aliased_tables = implode(".",$this->ar_aliased_tables).'.';
	$table_name = substr($item, 0, strpos($item, '.')+1);
	$item = (strpos($aliased_tables, $table_name) !== FALSE) ? $item = $item : $this->dbprefix.$item;
	}

	// This function may get "field >= 1", and need it to return ""field" >= 1"
	$lbound = ($first_word_only === TRUE) ? '' : '\|\s\|\(';

	$item = preg_replace('/(^'.$lbound.')([\w\d\-\_]+?)(\s\|\)\|$)/iS', '$1"$2"$3', $item);
	}
	else
	{
	return "\"{$item}\"";
	}

	$exceptions = array('AS', '/', '-', '%', '+', '*', 'OR', 'IS');

	foreach ($exceptions as $exception)
	{

	if (stristr($item, " \"{$exception}\" ") !== FALSE)
	{
	$item = preg_replace('/ "('.preg_quote($exception).')" /i', ' $1 ', $item);
	}
	}
	return $item;
	}

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

	/**
	* From Tables
	*
	* This function implicitly groups FROM tables so there is no confusion
	* about operator precedence in harmony with SQL standards
	*
	* @access public
	* @param type
	* @return type
	*/
	function _from_tables($tables)
	{
	if (! is_array($tables))
	{
	$tables = array($tables);
	}

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

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

	/**
	* Insert statement
	*
	* Generates a platform-specific insert string from the supplied data
	*
	* @access public
	* @param string the table name
	* @param array the insert keys
	* @param array the insert values
	* @return string
	*/
	function _insert($table, $keys, $values)
	{
	return "INSERT INTO ".$this->_escape_table($table)." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
	}

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

	/**
	* Update statement
	*
	* Generates a platform-specific update string from the supplied data
	*
	* @access public
	* @param string the table name
	* @param array the update data
	* @param array the where clause
	* @param array the orderby clause
	* @param array the limit clause
	* @return string
	*/
	function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
	{
	foreach($values as $key => $val)
	{
	$valstr[] = $key." = ".$val;
	}

	$limit = (!$limit) ? '' : ' LIMIT '.$limit;

	$orderby = (count($orderby) >= 1)?' ORDER BY '.implode(", ", $orderby):'';

	$sql = "UPDATE ".$this->_escape_table($table)." SET ".implode(', ', $valstr);
	$sql .= ($where != '' AND count($where) >=1) ? " WHERE ".implode(" ", $where) : '';
	$sql .= $orderby.$limit;

	return $sql;
	}

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

	/**
	* Truncate statement
	*
	* Generates a platform-specific truncate string from the supplied data
	* If the database does not support the truncate() command
	* This function maps to "DELETE FROM table"
	*
	* @access public
	* @param string the table name
	* @return string
	*/
	function _truncate($table)
	{
	return "TRUNCATE TABLE ".$this->_escape_table($table);
	}

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

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

	if (count($where) > 0 \|\| count($like) > 0)
	{
	$conditions = "\nWHERE ";
	$conditions .= implode("\n", $this->ar_where);

	if (count($where) > 0 && count($like) > 0)
	{
	$conditions .= " AND ";
	}
	$conditions .= implode("\n", $like);
	}

	$limit = (!$limit) ? '' : ' LIMIT '.$limit;

	return "DELETE FROM ".$table.$conditions.$limit;
	}

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

	/**
	* Limit string
	*
	* Generates a platform-specific LIMIT clause
	*
	* @access public
	* @param string the sql query string
	* @param integer the number of rows to limit the query to
	* @param integer the offset value
	* @return string
	*/
	function _limit($sql, $limit, $offset)
	{
	$limit = $offset + $limit;
	$newsql = "SELECT * FROM (select inner_query.*, rownum rnum FROM ($sql) inner_query WHERE rownum < $limit)";

	if ($offset != 0)
	{
	$newsql .= " WHERE rnum >= $offset";
	}

	// remember that we used limits
	$this->limit_used = TRUE;

	return $newsql;
	}

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

	/**
	* Close DB Connection
	*
	* @access public
	* @param resource
	* @return void
	*/
	function _close($conn_id)
	{
	@ocilogoff($conn_id);
	}


	}