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Codeigniter_Blog_App/system/database/DB_driver.php

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<?php
/**
* CodeIgniter
*
* An open source application development framework for PHP
*
* This content is released under the MIT License (MIT)
*
* Copyright (c) 2014 - 2016, British Columbia Institute of Technology
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* @package CodeIgniter
* @author EllisLab Dev Team
* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
* @copyright Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
* @license http://opensource.org/licenses/MIT MIT License
* @link https://codeigniter.com
* @since Version 1.0.0
* @filesource
*/
defined('BASEPATH') OR exit('No direct script access allowed');
/**
* Database Driver Class
*
* This is the platform-independent base DB implementation class.
* This class will not be called directly. Rather, the adapter
* class for the specific database will extend and instantiate it.
*
* @package CodeIgniter
* @subpackage Drivers
* @category Database
* @author EllisLab Dev Team
* @link https://codeigniter.com/user_guide/database/
*/
abstract class CI_DB_driver {
/**
* Data Source Name / Connect string
*
* @var string
*/
public $dsn;
/**
* Username
*
* @var string
*/
public $username;
/**
* Password
*
* @var string
*/
public $password;
/**
* Hostname
*
* @var string
*/
public $hostname;
/**
* Database name
*
* @var string
*/
public $database;
/**
* Database driver
*
* @var string
*/
public $dbdriver = 'mysqli';
/**
* Sub-driver
*
* @used-by CI_DB_pdo_driver
* @var string
*/
public $subdriver;
/**
* Table prefix
*
* @var string
*/
public $dbprefix = '';
/**
* Character set
*
* @var string
*/
public $char_set = 'utf8';
/**
* Collation
*
* @var string
*/
public $dbcollat = 'utf8_general_ci';
/**
* Encryption flag/data
*
* @var mixed
*/
public $encrypt = FALSE;
/**
* Swap Prefix
*
* @var string
*/
public $swap_pre = '';
/**
* Database port
*
* @var int
*/
public $port = '';
/**
* Persistent connection flag
*
* @var bool
*/
public $pconnect = FALSE;
/**
* Connection ID
*
* @var object|resource
*/
public $conn_id = FALSE;
/**
* Result ID
*
* @var object|resource
*/
public $result_id = FALSE;
/**
* Debug flag
*
* Whether to display error messages.
*
* @var bool
*/
public $db_debug = FALSE;
/**
* Benchmark time
*
* @var int
*/
public $benchmark = 0;
/**
* Executed queries count
*
* @var int
*/
public $query_count = 0;
/**
* Bind marker
*
* Character used to identify values in a prepared statement.
*
* @var string
*/
public $bind_marker = '?';
/**
* Save queries flag
*
* Whether to keep an in-memory history of queries for debugging purposes.
*
* @var bool
*/
public $save_queries = TRUE;
/**
* Queries list
*
* @see CI_DB_driver::$save_queries
* @var string[]
*/
public $queries = array();
/**
* Query times
*
* A list of times that queries took to execute.
*
* @var array
*/
public $query_times = array();
/**
* Data cache
*
* An internal generic value cache.
*
* @var array
*/
public $data_cache = array();
/**
* Transaction enabled flag
*
* @var bool
*/
public $trans_enabled = TRUE;
/**
* Strict transaction mode flag
*
* @var bool
*/
public $trans_strict = TRUE;
/**
* Transaction depth level
*
* @var int
*/
protected $_trans_depth = 0;
/**
* Transaction status flag
*
* Used with transactions to determine if a rollback should occur.
*
* @var bool
*/
protected $_trans_status = TRUE;
/**
* Transaction failure flag
*
* Used with transactions to determine if a transaction has failed.
*
* @var bool
*/
protected $_trans_failure = FALSE;
/**
* Cache On flag
*
* @var bool
*/
public $cache_on = FALSE;
/**
* Cache directory path
*
* @var bool
*/
public $cachedir = '';
/**
* Cache auto-delete flag
*
* @var bool
*/
public $cache_autodel = FALSE;
/**
* DB Cache object
*
* @see CI_DB_cache
* @var object
*/
public $CACHE;
/**
* Protect identifiers flag
*
* @var bool
*/
protected $_protect_identifiers = TRUE;
/**
* List of reserved identifiers
*
* Identifiers that must NOT be escaped.
*
* @var string[]
*/
protected $_reserved_identifiers = array('*');
/**
* Identifier escape character
*
* @var string
*/
protected $_escape_char = '"';
/**
* ESCAPE statement string
*
* @var string
*/
protected $_like_escape_str = " ESCAPE '%s' ";
/**
* ESCAPE character
*
* @var string
*/
protected $_like_escape_chr = '!';
/**
* ORDER BY random keyword
*
* @var array
*/
protected $_random_keyword = array('RAND()', 'RAND(%d)');
/**
* COUNT string
*
* @used-by CI_DB_driver::count_all()
* @used-by CI_DB_query_builder::count_all_results()
*
* @var string
*/
protected $_count_string = 'SELECT COUNT(*) AS ';
// --------------------------------------------------------------------
/**
* Class constructor
*
* @param array $params
* @return void
*/
public function __construct($params)
{
if (is_array($params))
{
foreach ($params as $key => $val)
{
$this->$key = $val;
}
}
log_message('info', 'Database Driver Class Initialized');
}
// --------------------------------------------------------------------
/**
* Initialize Database Settings
*
* @return bool
*/
public function initialize()
{
/* If an established connection is available, then there's
* no need to connect and select the database.
*
* Depending on the database driver, conn_id can be either
* boolean TRUE, a resource or an object.
*/
if ($this->conn_id)
{
return TRUE;
}
// ----------------------------------------------------------------
// Connect to the database and set the connection ID
$this->conn_id = $this->db_connect($this->pconnect);
// No connection resource? Check if there is a failover else throw an error
if ( ! $this->conn_id)
{
// Check if there is a failover set
if ( ! empty($this->failover) && is_array($this->failover))
{
// Go over all the failovers
foreach ($this->failover as $failover)
{
// Replace the current settings with those of the failover
foreach ($failover as $key => $val)
{
$this->$key = $val;
}
// Try to connect
$this->conn_id = $this->db_connect($this->pconnect);
// If a connection is made break the foreach loop
if ($this->conn_id)
{
break;
}
}
}
// We still don't have a connection?
if ( ! $this->conn_id)
{
log_message('error', 'Unable to connect to the database');
if ($this->db_debug)
{
$this->display_error('db_unable_to_connect');
}
return FALSE;
}
}
// Now we set the character set and that's all
return $this->db_set_charset($this->char_set);
}
// --------------------------------------------------------------------
/**
* DB connect
*
* This is just a dummy method that all drivers will override.
*
* @return mixed
*/
public function db_connect()
{
return TRUE;
}
// --------------------------------------------------------------------
/**
* Persistent database connection
*
* @return mixed
*/
public function db_pconnect()
{
return $this->db_connect(TRUE);
}
// --------------------------------------------------------------------
/**
* Reconnect
*
* Keep / reestablish the db connection if no queries have been
* sent for a length of time exceeding the server's idle timeout.
*
* This is just a dummy method to allow drivers without such
* functionality to not declare it, while others will override it.
*
* @return void
*/
public function reconnect()
{
}
// --------------------------------------------------------------------
/**
* Select database
*
* This is just a dummy method to allow drivers without such
* functionality to not declare it, while others will override it.
*
* @return bool
*/
public function db_select()
{
return TRUE;
}
// --------------------------------------------------------------------
/**
* Last error
*
* @return array
*/
public function error()
{
return array('code' => NULL, 'message' => NULL);
}
// --------------------------------------------------------------------
/**
* Set client character set
*
* @param string
* @return bool
*/
public function db_set_charset($charset)
{
if (method_exists($this, '_db_set_charset') && ! $this->_db_set_charset($charset))
{
log_message('error', 'Unable to set database connection charset: '.$charset);
if ($this->db_debug)
{
$this->display_error('db_unable_to_set_charset', $charset);
}
return FALSE;
}
return TRUE;
}
// --------------------------------------------------------------------
/**
* The name of the platform in use (mysql, mssql, etc...)
*
* @return string
*/
public function platform()
{
return $this->dbdriver;
}
// --------------------------------------------------------------------
/**
* Database version number
*
* Returns a string containing the version of the database being used.
* Most drivers will override this method.
*
* @return string
*/
public function version()
{
if (isset($this->data_cache['version']))
{
return $this->data_cache['version'];
}
if (FALSE === ($sql = $this->_version()))
{
return ($this->db_debug) ? $this->display_error('db_unsupported_function') : FALSE;
}
$query = $this->query($sql)->row();
return $this->data_cache['version'] = $query->ver;
}
// --------------------------------------------------------------------
/**
* Version number query string
*
* @return string
*/
protected function _version()
{
return 'SELECT VERSION() AS ver';
}
// --------------------------------------------------------------------
/**
* Execute the query
*
* Accepts an SQL string as input and returns a result object upon
* successful execution of a "read" type query. Returns boolean TRUE
* upon successful execution of a "write" type query. Returns boolean
* FALSE upon failure, and if the $db_debug variable is set to TRUE
* will raise an error.
*
* @param string $sql
* @param array $binds = FALSE An array of binding data
* @param bool $return_object = NULL
* @return mixed
*/
public function query($sql, $binds = FALSE, $return_object = NULL)
{
if ($sql === '')
{
log_message('error', 'Invalid query: '.$sql);
return ($this->db_debug) ? $this->display_error('db_invalid_query') : FALSE;
}
elseif ( ! is_bool($return_object))
{
$return_object = ! $this->is_write_type($sql);
}
// Verify table prefix and replace if necessary
if ($this->dbprefix !== '' && $this->swap_pre !== '' && $this->dbprefix !== $this->swap_pre)
{
$sql = preg_replace('/(\W)'.$this->swap_pre.'(\S+?)/', '\\1'.$this->dbprefix.'\\2', $sql);
}
// Compile binds if needed
if ($binds !== FALSE)
{
$sql = $this->compile_binds($sql, $binds);
}
// Is query caching enabled? If the query is a "read type"
// we will load the caching class and return the previously
// cached query if it exists
if ($this->cache_on === TRUE && $return_object === TRUE && $this->_cache_init())
{
$this->load_rdriver();
if (FALSE !== ($cache = $this->CACHE->read($sql)))
{
return $cache;
}
}
// Save the query for debugging
if ($this->save_queries === TRUE)
{
$this->queries[] = $sql;
}
// Start the Query Timer
$time_start = microtime(TRUE);
// Run the Query
if (FALSE === ($this->result_id = $this->simple_query($sql)))
{
if ($this->save_queries === TRUE)
{
$this->query_times[] = 0;
}
// This will trigger a rollback if transactions are being used
if ($this->_trans_depth !== 0)
{
$this->_trans_status = FALSE;
}
// Grab the error now, as we might run some additional queries before displaying the error
$error = $this->error();
// Log errors
log_message('error', 'Query error: '.$error['message'].' - Invalid query: '.$sql);
if ($this->db_debug)
{
// We call this function in order to roll-back queries
// if transactions are enabled. If we don't call this here
// the error message will trigger an exit, causing the
// transactions to remain in limbo.
while ($this->_trans_depth !== 0)
{
$trans_depth = $this->_trans_depth;
$this->trans_complete();
if ($trans_depth === $this->_trans_depth)
{
log_message('error', 'Database: Failure during an automated transaction commit/rollback!');
break;
}
}
// Display errors
return $this->display_error(array('Error Number: '.$error['code'], $error['message'], $sql));
}
return FALSE;
}
// Stop and aggregate the query time results
$time_end = microtime(TRUE);
$this->benchmark += $time_end - $time_start;
if ($this->save_queries === TRUE)
{
$this->query_times[] = $time_end - $time_start;
}
// Increment the query counter
$this->query_count++;
// Will we have a result object instantiated? If not - we'll simply return TRUE
if ($return_object !== TRUE)
{
// If caching is enabled we'll auto-cleanup any existing files related to this particular URI
if ($this->cache_on === TRUE && $this->cache_autodel === TRUE && $this->_cache_init())
{
$this->CACHE->delete();
}
return TRUE;
}
// Load and instantiate the result driver
$driver = $this->load_rdriver();
$RES = new $driver($this);
// Is query caching enabled? If so, we'll serialize the
// result object and save it to a cache file.
if ($this->cache_on === TRUE && $this->_cache_init())
{
// We'll create a new instance of the result object
// only without the platform specific driver since
// we can't use it with cached data (the query result
// resource ID won't be any good once we've cached the
// result object, so we'll have to compile the data
// and save it)
$CR = new CI_DB_result($this);
$CR->result_object = $RES->result_object();
$CR->result_array = $RES->result_array();
$CR->num_rows = $RES->num_rows();
// Reset these since cached objects can not utilize resource IDs.
$CR->conn_id = NULL;
$CR->result_id = NULL;
$this->CACHE->write($sql, $CR);
}
return $RES;
}
// --------------------------------------------------------------------
/**
* Load the result drivers
*
* @return string the name of the result class
*/
public function load_rdriver()
{
$driver = 'CI_DB_'.$this->dbdriver.'_result';
if ( ! class_exists($driver, FALSE))
{
require_once(BASEPATH.'database/DB_result.php');
require_once(BASEPATH.'database/drivers/'.$this->dbdriver.'/'.$this->dbdriver.'_result.php');
}
return $driver;
}
// --------------------------------------------------------------------
/**
* Simple Query
* This is a simplified version of the query() function. Internally
* we only use it when running transaction commands since they do
* not require all the features of the main query() function.
*
* @param string the sql query
* @return mixed
*/
public function simple_query($sql)
{
if ( ! $this->conn_id)
{
if ( ! $this->initialize())
{
return FALSE;
}
}
return $this->_execute($sql);
}
// --------------------------------------------------------------------
/**
* Disable Transactions
* This permits transactions to be disabled at run-time.
*
* @return void
*/
public function trans_off()
{
$this->trans_enabled = FALSE;
}
// --------------------------------------------------------------------
/**
* Enable/disable Transaction Strict Mode
*
* When strict mode is enabled, if you are running multiple groups of
* transactions, if one group fails all subsequent groups will be
* rolled back.
*
* If strict mode is disabled, each group is treated autonomously,
* meaning a failure of one group will not affect any others
*
* @param bool $mode = TRUE
* @return void
*/
public function trans_strict($mode = TRUE)
{
$this->trans_strict = is_bool($mode) ? $mode : TRUE;
}
// --------------------------------------------------------------------
/**
* Start Transaction
*
* @param bool $test_mode = FALSE
* @return bool
*/
public function trans_start($test_mode = FALSE)
{
if ( ! $this->trans_enabled)
{
return FALSE;
}
return $this->trans_begin($test_mode);
}
// --------------------------------------------------------------------
/**
* Complete Transaction
*
* @return bool
*/
public function trans_complete()
{
if ( ! $this->trans_enabled)
{
return FALSE;
}
// The query() function will set this flag to FALSE in the event that a query failed
if ($this->_trans_status === FALSE OR $this->_trans_failure === TRUE)
{
$this->trans_rollback();
// If we are NOT running in strict mode, we will reset
// the _trans_status flag so that subsequent groups of
// transactions will be permitted.
if ($this->trans_strict === FALSE)
{
$this->_trans_status = TRUE;
}
log_message('debug', 'DB Transaction Failure');
return FALSE;
}
return $this->trans_commit();
}
// --------------------------------------------------------------------
/**
* Lets you retrieve the transaction flag to determine if it has failed
*
* @return bool
*/
public function trans_status()
{
return $this->_trans_status;
}
// --------------------------------------------------------------------
/**
* Begin Transaction
*
* @param bool $test_mode
* @return bool
*/
public function trans_begin($test_mode = FALSE)
{
if ( ! $this->trans_enabled)
{
return FALSE;
}
// When transactions are nested we only begin/commit/rollback the outermost ones
elseif ($this->_trans_depth > 0)
{
$this->_trans_depth++;
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);
if ($this->_trans_begin())
{
$this->_trans_depth++;
return TRUE;
}
return FALSE;
}
// --------------------------------------------------------------------
/**
* Commit Transaction
*
* @return bool
*/
public function trans_commit()
{
if ( ! $this->trans_enabled OR $this->_trans_depth === 0)
{
return FALSE;
}
// When transactions are nested we only begin/commit/rollback the outermost ones
elseif ($this->_trans_depth > 1 OR $this->_trans_commit())
{
$this->_trans_depth--;
return TRUE;
}
return FALSE;
}
// --------------------------------------------------------------------
/**
* Rollback Transaction
*
* @return bool
*/
public function trans_rollback()
{
if ( ! $this->trans_enabled OR $this->_trans_depth === 0)
{
return FALSE;
}
// When transactions are nested we only begin/commit/rollback the outermost ones
elseif ($this->_trans_depth > 1 OR $this->_trans_rollback())
{
$this->_trans_depth--;
return TRUE;
}
return FALSE;
}
// --------------------------------------------------------------------
/**
* Compile Bindings
*
* @param string the sql statement
* @param array an array of bind data
* @return string
*/
public function compile_binds($sql, $binds)
{
if (empty($this->bind_marker) OR strpos($sql, $this->bind_marker) === FALSE)
{
return $sql;
}
elseif ( ! is_array($binds))
{
$binds = array($binds);
$bind_count = 1;
}
else
{
// Make sure we're using numeric keys
$binds = array_values($binds);
$bind_count = count($binds);
}
// We'll need the marker length later
$ml = strlen($this->bind_marker);
// Make sure not to replace a chunk inside a string that happens to match the bind marker
if ($c = preg_match_all("/'[^']*'/i", $sql, $matches))
{
$c = preg_match_all('/'.preg_quote($this->bind_marker, '/').'/i',
str_replace($matches[0],
str_replace($this->bind_marker, str_repeat(' ', $ml), $matches[0]),
$sql, $c),
$matches, PREG_OFFSET_CAPTURE);
// Bind values' count must match the count of markers in the query
if ($bind_count !== $c)
{
return $sql;
}
}
elseif (($c = preg_match_all('/'.preg_quote($this->bind_marker, '/').'/i', $sql, $matches, PREG_OFFSET_CAPTURE)) !== $bind_count)
{
return $sql;
}
do
{
$c--;
$escaped_value = $this->escape($binds[$c]);
if (is_array($escaped_value))
{
$escaped_value = '('.implode(',', $escaped_value).')';
}
$sql = substr_replace($sql, $escaped_value, $matches[0][$c][1], $ml);
}
while ($c !== 0);
return $sql;
}
// --------------------------------------------------------------------
/**
* Determines if a query is a "write" type.
*
* @param string An SQL query string
* @return bool
*/
public function is_write_type($sql)
{
return (bool) preg_match('/^\s*"?(SET|INSERT|UPDATE|DELETE|REPLACE|CREATE|DROP|TRUNCATE|LOAD|COPY|ALTER|RENAME|GRANT|REVOKE|LOCK|UNLOCK|REINDEX)\s/i', $sql);
}
// --------------------------------------------------------------------
/**
* Calculate the aggregate query elapsed time
*
* @param int The number of decimal places
* @return string
*/
public function elapsed_time($decimals = 6)
{
return number_format($this->benchmark, $decimals);
}
// --------------------------------------------------------------------
/**
* Returns the total number of queries
*
* @return int
*/
public function total_queries()
{
return $this->query_count;
}
// --------------------------------------------------------------------
/**
* Returns the last query that was executed
*
* @return string
*/
public function last_query()
{
return end($this->queries);
}
// --------------------------------------------------------------------
/**
* "Smart" Escape String
*
* Escapes data based on type
* Sets boolean and null types
*
* @param string
* @return mixed
*/
public function escape($str)
{
if (is_array($str))
{
$str = array_map(array(&$this, 'escape'), $str);
return $str;
}
elseif (is_string($str) OR (is_object($str) && method_exists($str, '__toString')))
{
return "'".$this->escape_str($str)."'";
}
elseif (is_bool($str))
{
return ($str === FALSE) ? 0 : 1;
}
elseif ($str === NULL)
{
return 'NULL';
}
return $str;
}
// --------------------------------------------------------------------
/**
* Escape String
*
* @param string|string[] $str Input string
* @param bool $like Whether or not the string will be used in a LIKE condition
* @return string
*/
public function escape_str($str, $like = FALSE)
{
if (is_array($str))
{
foreach ($str as $key => $val)
{
$str[$key] = $this->escape_str($val, $like);
}
return $str;
}
$str = $this->_escape_str($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 $str;
}
// --------------------------------------------------------------------
/**
* Escape LIKE String
*
* Calls the individual driver for platform
* specific escaping for LIKE conditions
*
* @param string|string[]
* @return mixed
*/
public function escape_like_str($str)
{
return $this->escape_str($str, TRUE);
}
// --------------------------------------------------------------------
/**
* Platform-dependant string escape
*
* @param string
* @return string
*/
protected function _escape_str($str)
{
return str_replace("'", "''", remove_invisible_characters($str));
}
// --------------------------------------------------------------------
/**
* Primary
*
* Retrieves the primary key. It assumes that the row in the first
* position is the primary key
*
* @param string $table Table name
* @return string
*/
public function primary($table)
{
$fields = $this->list_fields($table);
return is_array($fields) ? current($fields) : FALSE;
}
// --------------------------------------------------------------------
/**
* "Count All" query
*
* Generates a platform-specific query string that counts all records in
* the specified database
*
* @param string
* @return int
*/
public function count_all($table = '')
{
if ($table === '')
{
return 0;
}
$query = $this->query($this->_count_string.$this->escape_identifiers('numrows').' FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE));
if ($query->num_rows() === 0)
{
return 0;
}
$query = $query->row();
$this->_reset_select();
return (int) $query->numrows;
}
// --------------------------------------------------------------------
/**
* Returns an array of table names
*
* @param string $constrain_by_prefix = FALSE
* @return array
*/
public function list_tables($constrain_by_prefix = FALSE)
{
// Is there a cached result?
if (isset($this->data_cache['table_names']))
{
return $this->data_cache['table_names'];
}
if (FALSE === ($sql = $this->_list_tables($constrain_by_prefix)))
{
return ($this->db_debug) ? $this->display_error('db_unsupported_function') : FALSE;
}
$this->data_cache['table_names'] = array();
$query = $this->query($sql);
foreach ($query->result_array() as $row)
{
// Do we know from which column to get the table name?
if ( ! isset($key))
{
if (isset($row['table_name']))
{
$key = 'table_name';
}
elseif (isset($row['TABLE_NAME']))
{
$key = 'TABLE_NAME';
}
else
{
/* We have no other choice but to just get the first element's key.
* Due to array_shift() accepting its argument by reference, if
* E_STRICT is on, this would trigger a warning. So we'll have to
* assign it first.
*/
$key = array_keys($row);
$key = array_shift($key);
}
}
$this->data_cache['table_names'][] = $row[$key];
}
return $this->data_cache['table_names'];
}
// --------------------------------------------------------------------
/**
* Determine if a particular table exists
*
* @param string $table_name
* @return bool
*/
public function table_exists($table_name)
{
return in_array($this->protect_identifiers($table_name, TRUE, FALSE, FALSE), $this->list_tables());
}
// --------------------------------------------------------------------
/**
* Fetch Field Names
*
* @param string $table Table name
* @return array
*/
public function list_fields($table)
{
// Is there a cached result?
if (isset($this->data_cache['field_names'][$table]))
{
return $this->data_cache['field_names'][$table];
}
if (FALSE === ($sql = $this->_list_columns($table)))
{
return ($this->db_debug) ? $this->display_error('db_unsupported_function') : FALSE;
}
$query = $this->query($sql);
$this->data_cache['field_names'][$table] = array();
foreach ($query->result_array() as $row)
{
// Do we know from where to get the column's name?
if ( ! isset($key))
{
if (isset($row['column_name']))
{
$key = 'column_name';
}
elseif (isset($row['COLUMN_NAME']))
{
$key = 'COLUMN_NAME';
}
else
{
// We have no other choice but to just get the first element's key.
$key = key($row);
}
}
$this->data_cache['field_names'][$table][] = $row[$key];
}
return $this->data_cache['field_names'][$table];
}
// --------------------------------------------------------------------
/**
* Determine if a particular field exists
*
* @param string
* @param string
* @return bool
*/
public function field_exists($field_name, $table_name)
{
return in_array($field_name, $this->list_fields($table_name));
}
// --------------------------------------------------------------------
/**
* Returns an object with field data
*
* @param string $table the table name
* @return array
*/
public function field_data($table)
{
$query = $this->query($this->_field_data($this->protect_identifiers($table, TRUE, NULL, FALSE)));
return ($query) ? $query->field_data() : FALSE;
}
// --------------------------------------------------------------------
/**
* Escape the SQL Identifiers
*
* This function escapes column and table names
*
* @param mixed
* @return mixed
*/
public function escape_identifiers($item)
{
if ($this->_escape_char === '' OR empty($item) OR in_array($item, $this->_reserved_identifiers))
{
return $item;
}
elseif (is_array($item))
{
foreach ($item as $key => $value)
{
$item[$key] = $this->escape_identifiers($value);
}
return $item;
}
// Avoid breaking functions and literal values inside queries
elseif (ctype_digit($item) OR $item[0] === "'" OR ($this->_escape_char !== '"' && $item[0] === '"') OR strpos($item, '(') !== FALSE)
{
return $item;
}
static $preg_ec = array();
if (empty($preg_ec))
{
if (is_array($this->_escape_char))
{
$preg_ec = array(
preg_quote($this->_escape_char[0], '/'),
preg_quote($this->_escape_char[1], '/'),
$this->_escape_char[0],
$this->_escape_char[1]
);
}
else
{
$preg_ec[0] = $preg_ec[1] = preg_quote($this->_escape_char, '/');
$preg_ec[2] = $preg_ec[3] = $this->_escape_char;
}
}
foreach ($this->_reserved_identifiers as $id)
{
if (strpos($item, '.'.$id) !== FALSE)
{
return preg_replace('/'.$preg_ec[0].'?([^'.$preg_ec[1].'\.]+)'.$preg_ec[1].'?\./i', $preg_ec[2].'$1'.$preg_ec[3].'.', $item);
}
}
return preg_replace('/'.$preg_ec[0].'?([^'.$preg_ec[1].'\.]+)'.$preg_ec[1].'?(\.)?/i', $preg_ec[2].'$1'.$preg_ec[3].'$2', $item);
}
// --------------------------------------------------------------------
/**
* Generate an insert string
*
* @param string the table upon which the query will be performed
* @param array an associative array data of key/values
* @return string
*/
public function insert_string($table, $data)
{
$fields = $values = array();
foreach ($data as $key => $val)
{
$fields[] = $this->escape_identifiers($key);
$values[] = $this->escape($val);
}
return $this->_insert($this->protect_identifiers($table, TRUE, NULL, FALSE), $fields, $values);
}
// --------------------------------------------------------------------
/**
* Insert statement
*
* Generates a platform-specific insert string from the supplied data
*
* @param string the table name
* @param array the insert keys
* @param array the insert values
* @return string
*/
protected function _insert($table, $keys, $values)
{
return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
}
// --------------------------------------------------------------------
/**
* Generate an update string
*
* @param string the table upon which the query will be performed
* @param array an associative array data of key/values
* @param mixed the "where" statement
* @return string
*/
public function update_string($table, $data, $where)
{
if (empty($where))
{
return FALSE;
}
$this->where($where);
$fields = array();
foreach ($data as $key => $val)
{
$fields[$this->protect_identifiers($key)] = $this->escape($val);
}
$sql = $this->_update($this->protect_identifiers($table, TRUE, NULL, FALSE), $fields);
$this->_reset_write();
return $sql;
}
// --------------------------------------------------------------------
/**
* Update statement
*
* Generates a platform-specific update string from the supplied data
*
* @param string the table name
* @param array the update data
* @return string
*/
protected function _update($table, $values)
{
foreach ($values as $key => $val)
{
$valstr[] = $key.' = '.$val;
}
return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
.$this->_compile_wh('qb_where')
.$this->_compile_order_by()
.($this->qb_limit ? ' LIMIT '.$this->qb_limit : '');
}
// --------------------------------------------------------------------
/**
* Tests whether the string has an SQL operator
*
* @param string
* @return bool
*/
protected function _has_operator($str)
{
return (bool) preg_match('/(<|>|!|=|\sIS NULL|\sIS NOT NULL|\sEXISTS|\sBETWEEN|\sLIKE|\sIN\s*\(|\s)/i', trim($str));
}
// --------------------------------------------------------------------
/**
* Returns the SQL string operator
*
* @param string
* @return string
*/
protected function _get_operator($str)
{
static $_operators;
if (empty($_operators))
{
$_les = ($this->_like_escape_str !== '')
? '\s+'.preg_quote(trim(sprintf($this->_like_escape_str, $this->_like_escape_chr)), '/')
: '';
$_operators = array(
'\s*(?:<|>|!)?=\s*', // =, <=, >=, !=
'\s*<>?\s*', // <, <>
'\s*>\s*', // >
'\s+IS NULL', // IS NULL
'\s+IS NOT NULL', // IS NOT NULL
'\s+EXISTS\s*\(.*\)', // EXISTS(sql)
'\s+NOT EXISTS\s*\(.*\)', // NOT EXISTS(sql)
'\s+BETWEEN\s+', // BETWEEN value AND value
'\s+IN\s*\(.*\)', // IN(list)
'\s+NOT IN\s*\(.*\)', // NOT IN (list)
'\s+LIKE\s+\S.*('.$_les.')?', // LIKE 'expr'[ ESCAPE '%s']
'\s+NOT LIKE\s+\S.*('.$_les.')?' // NOT LIKE 'expr'[ ESCAPE '%s']
);
}
return preg_match('/'.implode('|', $_operators).'/i', $str, $match)
? $match[0] : FALSE;
}
// --------------------------------------------------------------------
/**
* Enables a native PHP function to be run, using a platform agnostic wrapper.
*
* @param string $function Function name
* @return mixed
*/
public function call_function($function)
{
$driver = ($this->dbdriver === 'postgre') ? 'pg_' : $this->dbdriver.'_';
if (FALSE === strpos($driver, $function))
{
$function = $driver.$function;
}
if ( ! function_exists($function))
{
return ($this->db_debug) ? $this->display_error('db_unsupported_function') : FALSE;
}
return (func_num_args() > 1)
? call_user_func_array($function, array_slice(func_get_args(), 1))
: call_user_func($function);
}
// --------------------------------------------------------------------
/**
* Set Cache Directory Path
*
* @param string the path to the cache directory
* @return void
*/
public function cache_set_path($path = '')
{
$this->cachedir = $path;
}
// --------------------------------------------------------------------
/**
* Enable Query Caching
*
* @return bool cache_on value
*/
public function cache_on()
{
return $this->cache_on = TRUE;
}
// --------------------------------------------------------------------
/**
* Disable Query Caching
*
* @return bool cache_on value
*/
public function cache_off()
{
return $this->cache_on = FALSE;
}
// --------------------------------------------------------------------
/**
* Delete the cache files associated with a particular URI
*
* @param string $segment_one = ''
* @param string $segment_two = ''
* @return bool
*/
public function cache_delete($segment_one = '', $segment_two = '')
{
return $this->_cache_init()
? $this->CACHE->delete($segment_one, $segment_two)
: FALSE;
}
// --------------------------------------------------------------------
/**
* Delete All cache files
*
* @return bool
*/
public function cache_delete_all()
{
return $this->_cache_init()
? $this->CACHE->delete_all()
: FALSE;
}
// --------------------------------------------------------------------
/**
* Initialize the Cache Class
*
* @return bool
*/
protected function _cache_init()
{
if ( ! class_exists('CI_DB_Cache', FALSE))
{
require_once(BASEPATH.'database/DB_cache.php');
}
elseif (is_object($this->CACHE))
{
return TRUE;
}
$this->CACHE = new CI_DB_Cache($this); // pass db object to support multiple db connections and returned db objects
return TRUE;
}
// --------------------------------------------------------------------
/**
* Close DB Connection
*
* @return void
*/
public function close()
{
if ($this->conn_id)
{
$this->_close();
$this->conn_id = FALSE;
}
}
// --------------------------------------------------------------------
/**
* Close DB Connection
*
* This method would be overridden by most of the drivers.
*
* @return void
*/
protected function _close()
{
$this->conn_id = FALSE;
}
// --------------------------------------------------------------------
/**
* Display an error message
*
* @param string the error message
* @param string any "swap" values
* @param bool whether to localize the message
* @return string sends the application/views/errors/error_db.php template
*/
public function display_error($error = '', $swap = '', $native = FALSE)
{
$LANG =& load_class('Lang', 'core');
$LANG->load('db');
$heading = $LANG->line('db_error_heading');
if ($native === TRUE)
{
$message = (array) $error;
}
else
{
$message = is_array($error) ? $error : array(str_replace('%s', $swap, $LANG->line($error)));
}
// Find the most likely culprit of the error by going through
// the backtrace until the source file is no longer in the
// database folder.
$trace = debug_backtrace();
foreach ($trace as $call)
{
if (isset($call['file'], $call['class']))
{
// We'll need this on Windows, as APPPATH and BASEPATH will always use forward slashes
if (DIRECTORY_SEPARATOR !== '/')
{
$call['file'] = str_replace('\\', '/', $call['file']);
}
if (strpos($call['file'], BASEPATH.'database') === FALSE && strpos($call['class'], 'Loader') === FALSE)
{
// Found it - use a relative path for safety
$message[] = 'Filename: '.str_replace(array(APPPATH, BASEPATH), '', $call['file']);
$message[] = 'Line Number: '.$call['line'];
break;
}
}
}
$error =& load_class('Exceptions', 'core');
echo $error->show_error($heading, $message, 'error_db');
exit(8); // EXIT_DATABASE
}
// --------------------------------------------------------------------
/**
* Protect Identifiers
*
* This function is used extensively by the Query Builder class, and by
* a couple functions in this class.
* It takes a column or table name (optionally with an alias) and inserts
* the table prefix onto it. Some logic is necessary in order to deal with
* column names that include the path. Consider a query like this:
*
* SELECT hostname.database.table.column AS c FROM hostname.database.table
*
* Or a query with aliasing:
*
* SELECT m.member_id, m.member_name FROM members AS m
*
* Since the column name can include up to four segments (host, DB, table, column)
* or also have an alias prefix, we need to do a bit of work to figure this out and
* insert the table prefix (if it exists) in the proper position, and escape only
* the correct identifiers.
*
* @param string
* @param bool
* @param mixed
* @param bool
* @return string
*/
public function protect_identifiers($item, $prefix_single = FALSE, $protect_identifiers = NULL, $field_exists = TRUE)
{
if ( ! is_bool($protect_identifiers))
{
$protect_identifiers = $this->_protect_identifiers;
}
if (is_array($item))
{
$escaped_array = array();
foreach ($item as $k => $v)
{
$escaped_array[$this->protect_identifiers($k)] = $this->protect_identifiers($v, $prefix_single, $protect_identifiers, $field_exists);
}
return $escaped_array;
}
// This is basically a bug fix for queries that use MAX, MIN, etc.
// If a parenthesis is found we know that we do not need to
// escape the data or add a prefix. There's probably a more graceful
// way to deal with this, but I'm not thinking of it -- Rick
//
// Added exception for single quotes as well, we don't want to alter
// literal strings. -- Narf
if (strcspn($item, "()'") !== strlen($item))
{
return $item;
}
// Convert tabs or multiple spaces into single spaces
$item = preg_replace('/\s+/', ' ', trim($item));
// If the item has an alias declaration we remove it and set it aside.
// Note: strripos() is used in order to support spaces in table names
if ($offset = strripos($item, ' AS '))
{
$alias = ($protect_identifiers)
? substr($item, $offset, 4).$this->escape_identifiers(substr($item, $offset + 4))
: substr($item, $offset);
$item = substr($item, 0, $offset);
}
elseif ($offset = strrpos($item, ' '))
{
$alias = ($protect_identifiers)
? ' '.$this->escape_identifiers(substr($item, $offset + 1))
: substr($item, $offset);
$item = substr($item, 0, $offset);
}
else
{
$alias = '';
}
// Break the string apart if it contains periods, then insert the table prefix
// in the correct location, assuming the period doesn't indicate that we're dealing
// with an alias. While we're at it, we will escape the components
if (strpos($item, '.') !== FALSE)
{
$parts = explode('.', $item);
// Does the first segment of the exploded item match
// one of the aliases previously identified? If so,
// we have nothing more to do other than escape the item
//
// NOTE: The ! empty() condition prevents this method
// from breaking when QB isn't enabled.
if ( ! empty($this->qb_aliased_tables) && in_array($parts[0], $this->qb_aliased_tables))
{
if ($protect_identifiers === TRUE)
{
foreach ($parts as $key => $val)
{
if ( ! in_array($val, $this->_reserved_identifiers))
{
$parts[$key] = $this->escape_identifiers($val);
}
}
$item = implode('.', $parts);
}
return $item.$alias;
}
// Is there a table prefix defined in the config file? If not, no need to do anything
if ($this->dbprefix !== '')
{
// We now add the table prefix based on some logic.
// Do we have 4 segments (hostname.database.table.column)?
// If so, we add the table prefix to the column name in the 3rd segment.
if (isset($parts[3]))
{
$i = 2;
}
// Do we have 3 segments (database.table.column)?
// If so, we add the table prefix to the column name in 2nd position
elseif (isset($parts[2]))
{
$i = 1;
}
// Do we have 2 segments (table.column)?
// If so, we add the table prefix to the column name in 1st segment
else
{
$i = 0;
}
// This flag is set when the supplied $item does not contain a field name.
// This can happen when this function is being called from a JOIN.
if ($field_exists === FALSE)
{
$i++;
}
// Verify table prefix and replace if necessary
if ($this->swap_pre !== '' && strpos($parts[$i], $this->swap_pre) === 0)
{
$parts[$i] = preg_replace('/^'.$this->swap_pre.'(\S+?)/', $this->dbprefix.'\\1', $parts[$i]);
}
// We only add the table prefix if it does not already exist
elseif (strpos($parts[$i], $this->dbprefix) !== 0)
{
$parts[$i] = $this->dbprefix.$parts[$i];
}
// Put the parts back together
$item = implode('.', $parts);
}
if ($protect_identifiers === TRUE)
{
$item = $this->escape_identifiers($item);
}
return $item.$alias;
}
// Is there a table prefix? If not, no need to insert it
if ($this->dbprefix !== '')
{
// Verify table prefix and replace if necessary
if ($this->swap_pre !== '' && strpos($item, $this->swap_pre) === 0)
{
$item = preg_replace('/^'.$this->swap_pre.'(\S+?)/', $this->dbprefix.'\\1', $item);
}
// Do we prefix an item with no segments?
elseif ($prefix_single === TRUE && strpos($item, $this->dbprefix) !== 0)
{
$item = $this->dbprefix.$item;
}
}
if ($protect_identifiers === TRUE && ! in_array($item, $this->_reserved_identifiers))
{
$item = $this->escape_identifiers($item);
}
return $item.$alias;
}
// --------------------------------------------------------------------
/**
* Dummy method that allows Query Builder class to be disabled
* and keep count_all() working.
*
* @return void
*/
protected function _reset_select()
{
}
}
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