system/database/drivers/postgre/postgre_driver.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 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
 */

/**
 * Postgre 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		EllisLab Dev Team
 * @link		http://codeigniter.com/user_guide/database/
 */
class CI_DB_postgre_driver extends CI_DB {

	public $dbdriver = 'postgre';

	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 = ' RANDOM()'; // database specific random keyword

	// Postgre-specific properties
	protected $_pg_dsn;

	/**
	 * Constructor
	 *
	 * Creates a DSN string to be used for db_connect() and db_pconnect()
	 *
	 * @return	void
	 */
	public function __construct($params)
	{
		parent::__construct($params);

		$components = array(
					'hostname'	=> 'host',
					'port'		=> 'port',
					'database'	=> 'dbname',
					'username'	=> 'user',
					'password'	=> 'password'
				);

		foreach ($components as $key => $val)
		{
			if (isset($this->$key) && $this->$key != '')
			{
				$this->_pg_dsn .= $val.'='.$this->$key.' ';
			}
		}

		if (strlen($this->_pg_dsn) > 0)
		{
			$this->_pg_dsn = rtrim($this->_pg_dsn);
		}
	}

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

	/**
	 * Non-persistent database connection
	 *
	 * @return	resource
	 */
	public function db_connect()
	{
		$ret = @pg_connect($this->_pg_dsn);
		if (is_resource($ret) && $this->char_set != '')
		{
			pg_set_client_encoding($ret, $this->char_set);
		}

		return $ret;
	}

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

	/**
	 * Persistent database connection
	 *
	 * @return	resource
	 */
	public function db_pconnect()
	{
		$ret = @pg_pconnect($this->_pg_dsn);
		if (is_resource($ret) && $this->char_set != '')
		{
			pg_set_client_encoding($ret, $this->char_set);
		}

		return $ret;
	}

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

	/**
	 * Reconnect
	 *
	 * Keep / reestablish the db connection if no queries have been
	 * sent for a length of time exceeding the server's idle timeout
	 *
	 * @return	void
	 */
	public function reconnect()
	{
		if (pg_ping($this->conn_id) === FALSE)
		{
			$this->conn_id = FALSE;
		}
	}

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

	/**
	 * Select the database
	 *
	 * @return	resource
	 */
	public function db_select()
	{
		// Not needed for Postgre so we'll return TRUE
		return TRUE;
	}

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

	/**
	 * Set client character set
	 *
	 * @param	string
	 * @param	string
	 * @return	bool
	 */
	public function db_set_charset($charset, $collation)
	{
		return (pg_set_client_encoding($this->conn_id, $charset) === 0);
	}

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

	/**
	 * Database version
	 *
	 * This method overrides the one from the base class, as if PHP was
	 * compiled with PostgreSQL version >= 7.4 libraries, we have a native
	 * function to get the server's version.
	 *
	 * @return	string
	 */
	public function version()
	{
		$version = pg_version($this->conn_id);

		/* If we don't have the server version string - fall back to
		 * the base driver class' method
		 */
		return isset($version['server']) ? $version['server'] : parent::version();
	}

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

	/**
	 * Version number query string
	 *
	 * @return	string
	 */
	protected function _version()
	{
		return 'SELECT version() AS ver';
	}

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

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

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

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

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

	/**
	 * Begin Transaction
	 *
	 * @param	bool
	 * @return	bool
	 */
	public function trans_begin($test_mode = FALSE)
	{
		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ( ! $this->trans_enabled OR $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);

		return (bool) @pg_query($this->conn_id, 'BEGIN');
	}

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

	/**
	 * Commit Transaction
	 *
	 * @return	bool
	 */
	public function trans_commit()
	{
		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
		{
			return TRUE;
		}

		return (bool) @pg_query($this->conn_id, 'COMMIT');
	}

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

	/**
	 * Rollback Transaction
	 *
	 * @return	bool
	 */
	public function trans_rollback()
	{
		// When transactions are nested we only begin/commit/rollback the outermost ones
		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
		{
			return TRUE;
		}

		return (bool) @pg_query($this->conn_id, 'ROLLBACK');
	}

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

	/**
	 * 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;
		}

		$str = pg_escape_string($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 @pg_affected_rows($this->result_id);
	}

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

	/**
	 * Insert ID
	 *
	 * @return	int
	 */
	public function insert_id()
	{
		$v = pg_version($this->conn_id);
		$v = isset($v['server']) ? $v['server'] : 0; // 'server' key is only available since PosgreSQL 7.4

		$table	= (func_num_args() > 0) ? func_get_arg(0) : NULL;
		$column	= (func_num_args() > 1) ? func_get_arg(1) : NULL;

		if ($table == NULL && $v >= '8.1')
		{
			$sql = 'SELECT LASTVAL() AS ins_id';
		}
		elseif ($table != NULL)
		{
			if ($column != NULL && $v >= '8.0')
			{
				$sql = 'SELECT pg_get_serial_sequence(\''.$table."', '".$column."') AS seq";
				$query = $this->query($sql);
				$query = $query->row();
				$seq = $query->seq;
			}
			else
			{
				// seq_name passed in table parameter
				$seq = $table;
			}

			$sql = 'SELECT CURRVAL(\''.$seq."') AS ins_id";
		}
		else
		{
			return pg_last_oid($this->result_id);
		}

		$query = $this->query($sql);
		$query = $query->row();
		return (int) $query->ins_id;
	}

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

	/**
	 * "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;
		}

		$query = $query->row();
		$this->_reset_select();
		return (int) $query->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 = "SELECT table_name FROM information_schema.tables WHERE table_schema = 'public'";

		if ($prefix_limit !== FALSE && $this->dbprefix != '')
		{
			return $sql." AND table_name LIKE '".$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($table = '')
	{
		return "SELECT column_name FROM information_schema.columns WHERE table_name = '".$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($table)
	{
		return 'SELECT * FROM '.$table.' LIMIT 1';
	}

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

	/**
	 * The error message string
	 *
	 * @return	string
	 */
	protected function _error_message()
	{
		return pg_last_error($this->conn_id);
	}

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

	/**
	 * The error message number
	 *
	 * @return	string
	 */
	protected function _error_number()
	{
		// Not supported in Postgre
		return '';
	}

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

	/**
	 * Escape the SQL Identifiers
	 *
	 * This function escapes column and table names
	 *
	 * @param	string
	 * @return	string
	 */
	public function _escape_identifiers($item)
	{
		if ($this->_escape_char == '')
		{
			return $item;
		}

		foreach ($this->_reserved_identifiers as $id)
		{
			if (strpos($item, '.'.$id) !== FALSE)
			{
				$item = str_replace('.', $this->_escape_char.'.', $item);

				// remove duplicates if the user already included the escape
				return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $this->_escape_char.$item);
			}
		}

		if (strpos($item, '.') !== FALSE)
		{
			$item = str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item);
		}

		// remove duplicates if the user already included the escape
		return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $this->_escape_char.$item.$this->_escape_char);
	}

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

	/**
	 * From Tables
	 *
	 * This function implicitly groups FROM tables so there is no confusion
	 * about operator precedence in harmony with SQL standards
	 *
	 * @param	string	table name
	 * @return	string
	 */
	protected 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
	 *
	 * @param	string	the table name
	 * @param	array	the insert keys
	 * @param	array	the insert values
	 * @return	string
	 */
	protected function _insert($table, $keys, $values)
	{
		return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
	}

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

	/**
	 * Insert_batch statement
	 *
	 * Generates a platform-specific insert string from the supplied data
	 *
	 * @param   string  the table name
	 * @param   array   the insert keys
	 * @param   array   the insert values
	 * @return  string
	 */
	protected function _insert_batch($table, $keys, $values)
	{
		return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES '.implode(', ', $values);
	}

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

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

		return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
			.(($where != '' && count($where) > 0) ? ' WHERE '.implode(' ', $where) : '')
			.(count($orderby) > 0 ? ' ORDER BY '.implode(', ', $orderby) : '')
			.( ! $limit ? '' : ' LIMIT '.$limit);
	}

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

	/**
	 * 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"
	 *
	 * @param	string	the table name
	 * @return	string
	 */
	protected function _truncate($table)
	{
		return 'TRUNCATE '.$table;
	}

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

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

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

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

		return 'DELETE FROM '.$table.$conditions.( ! $limit ? '' : ' LIMIT '.$limit);
	}

	// --------------------------------------------------------------------
	/**
	 * 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 $sql.' LIMIT '.$limit.($offset == 0 ? '' : ' OFFSET '.$offset);
	}

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

	/**
	 * Close DB Connection
	 *
	 * @param	resource
	 * @return	void
	 */
	protected function _close($conn_id)
	{
		@pg_close($conn_id);
	}

}

/* End of file postgre_driver.php */
/* Location: ./system/database/drivers/postgre/postgre_driver.php */