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DB_driver.php

Last change on this file was 289, checked in by dungnv, 11 years ago

File size: 31.9 KB

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1	<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
2	/**
3	* CodeIgniter
4	*
5	* An open source application development framework for PHP 5.1.6 or newer
6	*
7	* @package CodeIgniter
8	* @author ExpressionEngine Dev Team
9	* @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
10	* @license http://codeigniter.com/user_guide/license.html
11	* @link http://codeigniter.com
12	* @since Version 1.0
13	* @filesource
14	*/
15
16	// ------------------------------------------------------------------------
17
18	/**
19	* Database Driver Class
20	*
21	* This is the platform-independent base DB implementation class.
22	* This class will not be called directly. Rather, the adapter
23	* class for the specific database will extend and instantiate it.
24	*
25	* @package CodeIgniter
26	* @subpackage Drivers
27	* @category Database
28	* @author ExpressionEngine Dev Team
29	* @link http://codeigniter.com/user_guide/database/
30	*/
31	class CI_DB_driver {
32
33	var $username;
34	var $password;
35	var $hostname;
36	var $database;
37	var $dbdriver = 'mysql';
38	var $dbprefix = '';
39	var $char_set = 'utf8';
40	var $dbcollat = 'utf8_general_ci';
41	var $autoinit = TRUE; // Whether to automatically initialize the DB
42	var $swap_pre = '';
43	var $port = '';
44	var $pconnect = FALSE;
45	var $conn_id = FALSE;
46	var $result_id = FALSE;
47	var $db_debug = FALSE;
48	var $benchmark = 0;
49	var $query_count = 0;
50	var $bind_marker = '?';
51	var $save_queries = TRUE;
52	var $queries = array();
53	var $query_times = array();
54	var $data_cache = array();
55	var $trans_enabled = TRUE;
56	var $trans_strict = TRUE;
57	var $_trans_depth = 0;
58	var $_trans_status = TRUE; // Used with transactions to determine if a rollback should occur
59	var $cache_on = FALSE;
60	var $cachedir = '';
61	var $cache_autodel = FALSE;
62	var $CACHE; // The cache class object
63
64	// Private variables
65	var $_protect_identifiers = TRUE;
66	var $_reserved_identifiers = array('*'); // Identifiers that should NOT be escaped
67
68	// These are use with Oracle
69	var $stmt_id;
70	var $curs_id;
71	var $limit_used;
72
73
74
75	/**
76	* Constructor. Accepts one parameter containing the database
77	* connection settings.
78	*
79	* @param array
80	*/
81	function __construct($params)
82	{
83	if (is_array($params))
84	{
85	foreach ($params as $key => $val)
86	{
87	$this->$key = $val;
88	}
89	}
90
91	log_message('debug', 'Database Driver Class Initialized');
92	}
93
94	// --------------------------------------------------------------------
95
96	/**
97	* Initialize Database Settings
98	*
99	* @access private Called by the constructor
100	* @param mixed
101	* @return void
102	*/
103	function initialize()
104	{
105	// If an existing connection resource is available
106	// there is no need to connect and select the database
107	if (is_resource($this->conn_id) OR is_object($this->conn_id))
108	{
109	return TRUE;
110	}
111
112	// ----------------------------------------------------------------
113
114	// Connect to the database and set the connection ID
115	$this->conn_id = ($this->pconnect == FALSE) ? $this->db_connect() : $this->db_pconnect();
116
117	// No connection resource? Throw an error
118	if ( ! $this->conn_id)
119	{
120	log_message('error', 'Unable to connect to the database');
121
122	if ($this->db_debug)
123	{
124	$this->display_error('db_unable_to_connect');
125	}
126	return FALSE;
127	}
128
129	// ----------------------------------------------------------------
130
131	// Select the DB... assuming a database name is specified in the config file
132	if ($this->database != '')
133	{
134	if ( ! $this->db_select())
135	{
136	log_message('error', 'Unable to select database: '.$this->database);
137
138	if ($this->db_debug)
139	{
140	$this->display_error('db_unable_to_select', $this->database);
141	}
142	return FALSE;
143	}
144	else
145	{
146	// We've selected the DB. Now we set the character set
147	if ( ! $this->db_set_charset($this->char_set, $this->dbcollat))
148	{
149	return FALSE;
150	}
151
152	return TRUE;
153	}
154	}
155
156	return TRUE;
157	}
158
159	// --------------------------------------------------------------------
160
161	/**
162	* Set client character set
163	*
164	* @access public
165	* @param string
166	* @param string
167	* @return resource
168	*/
169	function db_set_charset($charset, $collation)
170	{
171	if ( ! $this->_db_set_charset($this->char_set, $this->dbcollat))
172	{
173	log_message('error', 'Unable to set database connection charset: '.$this->char_set);
174
175	if ($this->db_debug)
176	{
177	$this->display_error('db_unable_to_set_charset', $this->char_set);
178	}
179
180	return FALSE;
181	}
182
183	return TRUE;
184	}
185
186	// --------------------------------------------------------------------
187
188	/**
189	* The name of the platform in use (mysql, mssql, etc...)
190	*
191	* @access public
192	* @return string
193	*/
194	function platform()
195	{
196	return $this->dbdriver;
197	}
198
199	// --------------------------------------------------------------------
200
201	/**
202	* Database Version Number. Returns a string containing the
203	* version of the database being used
204	*
205	* @access public
206	* @return string
207	*/
208	function version()
209	{
210	if (FALSE === ($sql = $this->_version()))
211	{
212	if ($this->db_debug)
213	{
214	return $this->display_error('db_unsupported_function');
215	}
216	return FALSE;
217	}
218
219	// Some DBs have functions that return the version, and don't run special
220	// SQL queries per se. In these instances, just return the result.
221	$driver_version_exceptions = array('oci8', 'sqlite', 'cubrid');
222
223	if (in_array($this->dbdriver, $driver_version_exceptions))
224	{
225	return $sql;
226	}
227	else
228	{
229	$query = $this->query($sql);
230	return $query->row('ver');
231	}
232	}
233
234	// --------------------------------------------------------------------
235
236	/**
237	* Execute the query
238	*
239	* Accepts an SQL string as input and returns a result object upon
240	* successful execution of a "read" type query. Returns boolean TRUE
241	* upon successful execution of a "write" type query. Returns boolean
242	* FALSE upon failure, and if the $db_debug variable is set to TRUE
243	* will raise an error.
244	*
245	* @access public
246	* @param string An SQL query string
247	* @param array An array of binding data
248	* @return mixed
249	*/
250	function query($sql, $binds = FALSE, $return_object = TRUE)
251	{
252	if ($sql == '')
253	{
254	if ($this->db_debug)
255	{
256	log_message('error', 'Invalid query: '.$sql);
257	return $this->display_error('db_invalid_query');
258	}
259	return FALSE;
260	}
261
262	// Verify table prefix and replace if necessary
263	if ( ($this->dbprefix != '' AND $this->swap_pre != '') AND ($this->dbprefix != $this->swap_pre) )
264	{
265	$sql = preg_replace("/(\W)".$this->swap_pre."(\S+?)/", "\\1".$this->dbprefix."\\2", $sql);
266	}
267
268	// Compile binds if needed
269	if ($binds !== FALSE)
270	{
271	$sql = $this->compile_binds($sql, $binds);
272	}
273
274	// Is query caching enabled? If the query is a "read type"
275	// we will load the caching class and return the previously
276	// cached query if it exists
277	if ($this->cache_on == TRUE AND stristr($sql, 'SELECT'))
278	{
279	if ($this->_cache_init())
280	{
281	$this->load_rdriver();
282	if (FALSE !== ($cache = $this->CACHE->read($sql)))
283	{
284	return $cache;
285	}
286	}
287	}
288
289	// Save the query for debugging
290	if ($this->save_queries == TRUE)
291	{
292	$this->queries[] = $sql;
293	}
294
295	// Start the Query Timer
296	$time_start = list($sm, $ss) = explode(' ', microtime());
297
298	// Run the Query
299	if (FALSE === ($this->result_id = $this->simple_query($sql)))
300	{
301	if ($this->save_queries == TRUE)
302	{
303	$this->query_times[] = 0;
304	}
305
306	// This will trigger a rollback if transactions are being used
307	$this->_trans_status = FALSE;
308
309	if ($this->db_debug)
310	{
311	// grab the error number and message now, as we might run some
312	// additional queries before displaying the error
313	$error_no = $this->_error_number();
314	$error_msg = $this->_error_message();
315
316	// We call this function in order to roll-back queries
317	// if transactions are enabled. If we don't call this here
318	// the error message will trigger an exit, causing the
319	// transactions to remain in limbo.
320	$this->trans_complete();
321
322	// Log and display errors
323	log_message('error', 'Query error: '.$error_msg);
324	return $this->display_error(
325	array(
326	'Error Number: '.$error_no,
327	$error_msg,
328	$sql
329	)
330	);
331	}
332
333	return FALSE;
334	}
335
336	// Stop and aggregate the query time results
337	$time_end = list($em, $es) = explode(' ', microtime());
338	$this->benchmark += ($em + $es) - ($sm + $ss);
339
340	if ($this->save_queries == TRUE)
341	{
342	$this->query_times[] = ($em + $es) - ($sm + $ss);
343	}
344
345	// Increment the query counter
346	$this->query_count++;
347
348	// Was the query a "write" type?
349	// If so we'll simply return true
350	if ($this->is_write_type($sql) === TRUE)
351	{
352	// If caching is enabled we'll auto-cleanup any
353	// existing files related to this particular URI
354	if ($this->cache_on == TRUE AND $this->cache_autodel == TRUE AND $this->_cache_init())
355	{
356	$this->CACHE->delete();
357	}
358
359	return TRUE;
360	}
361
362	// Return TRUE if we don't need to create a result object
363	// Currently only the Oracle driver uses this when stored
364	// procedures are used
365	if ($return_object !== TRUE)
366	{
367	return TRUE;
368	}
369
370	// Load and instantiate the result driver
371
372	$driver = $this->load_rdriver();
373	$RES = new $driver();
374	$RES->conn_id = $this->conn_id;
375	$RES->result_id = $this->result_id;
376
377	if ($this->dbdriver == 'oci8')
378	{
379	$RES->stmt_id = $this->stmt_id;
380	$RES->curs_id = NULL;
381	$RES->limit_used = $this->limit_used;
382	$this->stmt_id = FALSE;
383	}
384
385	// oci8 vars must be set before calling this
386	$RES->num_rows = $RES->num_rows();
387
388	// Is query caching enabled? If so, we'll serialize the
389	// result object and save it to a cache file.
390	if ($this->cache_on == TRUE AND $this->_cache_init())
391	{
392	// We'll create a new instance of the result object
393	// only without the platform specific driver since
394	// we can't use it with cached data (the query result
395	// resource ID won't be any good once we've cached the
396	// result object, so we'll have to compile the data
397	// and save it)
398	$CR = new CI_DB_result();
399	$CR->num_rows = $RES->num_rows();
400	$CR->result_object = $RES->result_object();
401	$CR->result_array = $RES->result_array();
402
403	// Reset these since cached objects can not utilize resource IDs.
404	$CR->conn_id = NULL;
405	$CR->result_id = NULL;
406
407	$this->CACHE->write($sql, $CR);
408	}
409
410	return $RES;
411	}
412
413	// --------------------------------------------------------------------
414
415	/**
416	* Load the result drivers
417	*
418	* @access public
419	* @return string the name of the result class
420	*/
421	function load_rdriver()
422	{
423	$driver = 'CI_DB_'.$this->dbdriver.'_result';
424
425	if ( ! class_exists($driver))
426	{
427	include_once(BASEPATH.'database/DB_result.php');
428	include_once(BASEPATH.'database/drivers/'.$this->dbdriver.'/'.$this->dbdriver.'_result.php');
429	}
430
431	return $driver;
432	}
433
434	// --------------------------------------------------------------------
435
436	/**
437	* Simple Query
438	* This is a simplified version of the query() function. Internally
439	* we only use it when running transaction commands since they do
440	* not require all the features of the main query() function.
441	*
442	* @access public
443	* @param string the sql query
444	* @return mixed
445	*/
446	function simple_query($sql)
447	{
448	if ( ! $this->conn_id)
449	{
450	$this->initialize();
451	}
452
453	return $this->_execute($sql);
454	}
455
456	// --------------------------------------------------------------------
457
458	/**
459	* Disable Transactions
460	* This permits transactions to be disabled at run-time.
461	*
462	* @access public
463	* @return void
464	*/
465	function trans_off()
466	{
467	$this->trans_enabled = FALSE;
468	}
469
470	// --------------------------------------------------------------------
471
472	/**
473	* Enable/disable Transaction Strict Mode
474	* When strict mode is enabled, if you are running multiple groups of
475	* transactions, if one group fails all groups will be rolled back.
476	* If strict mode is disabled, each group is treated autonomously, meaning
477	* a failure of one group will not affect any others
478	*
479	* @access public
480	* @return void
481	*/
482	function trans_strict($mode = TRUE)
483	{
484	$this->trans_strict = is_bool($mode) ? $mode : TRUE;
485	}
486
487	// --------------------------------------------------------------------
488
489	/**
490	* Start Transaction
491	*
492	* @access public
493	* @return void
494	*/
495	function trans_start($test_mode = FALSE)
496	{
497	if ( ! $this->trans_enabled)
498	{
499	return FALSE;
500	}
501
502	// When transactions are nested we only begin/commit/rollback the outermost ones
503	if ($this->_trans_depth > 0)
504	{
505	$this->_trans_depth += 1;
506	return;
507	}
508
509	$this->trans_begin($test_mode);
510	}
511
512	// --------------------------------------------------------------------
513
514	/**
515	* Complete Transaction
516	*
517	* @access public
518	* @return bool
519	*/
520	function trans_complete()
521	{
522	if ( ! $this->trans_enabled)
523	{
524	return FALSE;
525	}
526
527	// When transactions are nested we only begin/commit/rollback the outermost ones
528	if ($this->_trans_depth > 1)
529	{
530	$this->_trans_depth -= 1;
531	return TRUE;
532	}
533
534	// The query() function will set this flag to FALSE in the event that a query failed
535	if ($this->_trans_status === FALSE)
536	{
537	$this->trans_rollback();
538
539	// If we are NOT running in strict mode, we will reset
540	// the _trans_status flag so that subsequent groups of transactions
541	// will be permitted.
542	if ($this->trans_strict === FALSE)
543	{
544	$this->_trans_status = TRUE;
545	}
546
547	log_message('debug', 'DB Transaction Failure');
548	return FALSE;
549	}
550
551	$this->trans_commit();
552	return TRUE;
553	}
554
555	// --------------------------------------------------------------------
556
557	/**
558	* Lets you retrieve the transaction flag to determine if it has failed
559	*
560	* @access public
561	* @return bool
562	*/
563	function trans_status()
564	{
565	return $this->_trans_status;
566	}
567
568	// --------------------------------------------------------------------
569
570	/**
571	* Compile Bindings
572	*
573	* @access public
574	* @param string the sql statement
575	* @param array an array of bind data
576	* @return string
577	*/
578	function compile_binds($sql, $binds)
579	{
580	if (strpos($sql, $this->bind_marker) === FALSE)
581	{
582	return $sql;
583	}
584
585	if ( ! is_array($binds))
586	{
587	$binds = array($binds);
588	}
589
590	// Get the sql segments around the bind markers
591	$segments = explode($this->bind_marker, $sql);
592
593	// The count of bind should be 1 less then the count of segments
594	// If there are more bind arguments trim it down
595	if (count($binds) >= count($segments)) {
596	$binds = array_slice($binds, 0, count($segments)-1);
597	}
598
599	// Construct the binded query
600	$result = $segments[0];
601	$i = 0;
602	foreach ($binds as $bind)
603	{
604	$result .= $this->escape($bind);
605	$result .= $segments[++$i];
606	}
607
608	return $result;
609	}
610
611	// --------------------------------------------------------------------
612
613	/**
614	* Determines if a query is a "write" type.
615	*
616	* @access public
617	* @param string An SQL query string
618	* @return boolean
619	*/
620	function is_write_type($sql)
621	{
622	if ( ! preg_match('/^\s*"?(SET\|INSERT\|UPDATE\|DELETE\|REPLACE\|CREATE\|DROP\|TRUNCATE\|LOAD DATA\|COPY\|ALTER\|GRANT\|REVOKE\|LOCK\|UNLOCK)\s+/i', $sql))
623	{
624	return FALSE;
625	}
626	return TRUE;
627	}
628
629	// --------------------------------------------------------------------
630
631	/**
632	* Calculate the aggregate query elapsed time
633	*
634	* @access public
635	* @param integer The number of decimal places
636	* @return integer
637	*/
638	function elapsed_time($decimals = 6)
639	{
640	return number_format($this->benchmark, $decimals);
641	}
642
643	// --------------------------------------------------------------------
644
645	/**
646	* Returns the total number of queries
647	*
648	* @access public
649	* @return integer
650	*/
651	function total_queries()
652	{
653	return $this->query_count;
654	}
655
656	// --------------------------------------------------------------------
657
658	/**
659	* Returns the last query that was executed
660	*
661	* @access public
662	* @return void
663	*/
664	function last_query()
665	{
666	return end($this->queries);
667	}
668
669	// --------------------------------------------------------------------
670
671	/**
672	* "Smart" Escape String
673	*
674	* Escapes data based on type
675	* Sets boolean and null types
676	*
677	* @access public
678	* @param string
679	* @return mixed
680	*/
681	function escape($str)
682	{
683	if (is_string($str))
684	{
685	$str = "'".$this->escape_str($str)."'";
686	}
687	elseif (is_bool($str))
688	{
689	$str = ($str === FALSE) ? 0 : 1;
690	}
691	elseif (is_null($str))
692	{
693	$str = 'NULL';
694	}
695
696	return $str;
697	}
698
699	// --------------------------------------------------------------------
700
701	/**
702	* Escape LIKE String
703	*
704	* Calls the individual driver for platform
705	* specific escaping for LIKE conditions
706	*
707	* @access public
708	* @param string
709	* @return mixed
710	*/
711	function escape_like_str($str)
712	{
713	return $this->escape_str($str, TRUE);
714	}
715
716	// --------------------------------------------------------------------
717
718	/**
719	* Primary
720	*
721	* Retrieves the primary key. It assumes that the row in the first
722	* position is the primary key
723	*
724	* @access public
725	* @param string the table name
726	* @return string
727	*/
728	function primary($table = '')
729	{
730	$fields = $this->list_fields($table);
731
732	if ( ! is_array($fields))
733	{
734	return FALSE;
735	}
736
737	return current($fields);
738	}
739
740	// --------------------------------------------------------------------
741
742	/**
743	* Returns an array of table names
744	*
745	* @access public
746	* @return array
747	*/
748	function list_tables($constrain_by_prefix = FALSE)
749	{
750	// Is there a cached result?
751	if (isset($this->data_cache['table_names']))
752	{
753	return $this->data_cache['table_names'];
754	}
755
756	if (FALSE === ($sql = $this->_list_tables($constrain_by_prefix)))
757	{
758	if ($this->db_debug)
759	{
760	return $this->display_error('db_unsupported_function');
761	}
762	return FALSE;
763	}
764
765	$retval = array();
766	$query = $this->query($sql);
767
768	if ($query->num_rows() > 0)
769	{
770	foreach ($query->result_array() as $row)
771	{
772	if (isset($row['TABLE_NAME']))
773	{
774	$retval[] = $row['TABLE_NAME'];
775	}
776	else
777	{
778	$retval[] = array_shift($row);
779	}
780	}
781	}
782
783	$this->data_cache['table_names'] = $retval;
784	return $this->data_cache['table_names'];
785	}
786
787	// --------------------------------------------------------------------
788
789	/**
790	* Determine if a particular table exists
791	* @access public
792	* @return boolean
793	*/
794	function table_exists($table_name)
795	{
796	return ( ! in_array($this->_protect_identifiers($table_name, TRUE, FALSE, FALSE), $this->list_tables())) ? FALSE : TRUE;
797	}
798
799	// --------------------------------------------------------------------
800
801	/**
802	* Fetch MySQL Field Names
803	*
804	* @access public
805	* @param string the table name
806	* @return array
807	*/
808	function list_fields($table = '')
809	{
810	// Is there a cached result?
811	if (isset($this->data_cache['field_names'][$table]))
812	{
813	return $this->data_cache['field_names'][$table];
814	}
815
816	if ($table == '')
817	{
818	if ($this->db_debug)
819	{
820	return $this->display_error('db_field_param_missing');
821	}
822	return FALSE;
823	}
824
825	if (FALSE === ($sql = $this->_list_columns($table)))
826	{
827	if ($this->db_debug)
828	{
829	return $this->display_error('db_unsupported_function');
830	}
831	return FALSE;
832	}
833
834	$query = $this->query($sql);
835
836	$retval = array();
837	foreach ($query->result_array() as $row)
838	{
839	if (isset($row['COLUMN_NAME']))
840	{
841	$retval[] = $row['COLUMN_NAME'];
842	}
843	else
844	{
845	$retval[] = current($row);
846	}
847	}
848
849	$this->data_cache['field_names'][$table] = $retval;
850	return $this->data_cache['field_names'][$table];
851	}
852
853	// --------------------------------------------------------------------
854
855	/**
856	* Determine if a particular field exists
857	* @access public
858	* @param string
859	* @param string
860	* @return boolean
861	*/
862	function field_exists($field_name, $table_name)
863	{
864	return ( ! in_array($field_name, $this->list_fields($table_name))) ? FALSE : TRUE;
865	}
866
867	// --------------------------------------------------------------------
868
869	/**
870	* Returns an object with field data
871	*
872	* @access public
873	* @param string the table name
874	* @return object
875	*/
876	function field_data($table = '')
877	{
878	if ($table == '')
879	{
880	if ($this->db_debug)
881	{
882	return $this->display_error('db_field_param_missing');
883	}
884	return FALSE;
885	}
886
887	$query = $this->query($this->_field_data($this->_protect_identifiers($table, TRUE, NULL, FALSE)));
888
889	return $query->field_data();
890	}
891
892	// --------------------------------------------------------------------
893
894	/**
895	* Generate an insert string
896	*
897	* @access public
898	* @param string the table upon which the query will be performed
899	* @param array an associative array data of key/values
900	* @return string
901	*/
902	function insert_string($table, $data)
903	{
904	$fields = array();
905	$values = array();
906
907	foreach ($data as $key => $val)
908	{
909	$fields[] = $this->_escape_identifiers($key);
910	$values[] = $this->escape($val);
911	}
912
913	return $this->_insert($this->_protect_identifiers($table, TRUE, NULL, FALSE), $fields, $values);
914	}
915
916	// --------------------------------------------------------------------
917
918	/**
919	* Generate an update string
920	*
921	* @access public
922	* @param string the table upon which the query will be performed
923	* @param array an associative array data of key/values
924	* @param mixed the "where" statement
925	* @return string
926	*/
927	function update_string($table, $data, $where)
928	{
929	if ($where == '')
930	{
931	return false;
932	}
933
934	$fields = array();
935	foreach ($data as $key => $val)
936	{
937	$fields[$this->_protect_identifiers($key)] = $this->escape($val);
938	}
939
940	if ( ! is_array($where))
941	{
942	$dest = array($where);
943	}
944	else
945	{
946	$dest = array();
947	foreach ($where as $key => $val)
948	{
949	$prefix = (count($dest) == 0) ? '' : ' AND ';
950
951	if ($val !== '')
952	{
953	if ( ! $this->_has_operator($key))
954	{
955	$key .= ' =';
956	}
957
958	$val = ' '.$this->escape($val);
959	}
960
961	$dest[] = $prefix.$key.$val;
962	}
963	}
964
965	return $this->_update($this->_protect_identifiers($table, TRUE, NULL, FALSE), $fields, $dest);
966	}
967
968	// --------------------------------------------------------------------
969
970	/**
971	* Tests whether the string has an SQL operator
972	*
973	* @access private
974	* @param string
975	* @return bool
976	*/
977	function _has_operator($str)
978	{
979	$str = trim($str);
980	if ( ! preg_match("/(\s\|<\|>\|!\|=\|is null\|is not null)/i", $str))
981	{
982	return FALSE;
983	}
984
985	return TRUE;
986	}
987
988	// --------------------------------------------------------------------
989
990	/**
991	* Enables a native PHP function to be run, using a platform agnostic wrapper.
992	*
993	* @access public
994	* @param string the function name
995	* @param mixed any parameters needed by the function
996	* @return mixed
997	*/
998	function call_function($function)
999	{
1000	$driver = ($this->dbdriver == 'postgre') ? 'pg_' : $this->dbdriver.'_';
1001
1002	if (FALSE === strpos($driver, $function))
1003	{
1004	$function = $driver.$function;
1005	}
1006
1007	if ( ! function_exists($function))
1008	{
1009	if ($this->db_debug)
1010	{
1011	return $this->display_error('db_unsupported_function');
1012	}
1013	return FALSE;
1014	}
1015	else
1016	{
1017	$args = (func_num_args() > 1) ? array_splice(func_get_args(), 1) : null;
1018	if (is_null($args))
1019	{
1020	return call_user_func($function);
1021	}
1022	else
1023	{
1024	return call_user_func_array($function, $args);
1025	}
1026	}
1027	}
1028
1029	// --------------------------------------------------------------------
1030
1031	/**
1032	* Set Cache Directory Path
1033	*
1034	* @access public
1035	* @param string the path to the cache directory
1036	* @return void
1037	*/
1038	function cache_set_path($path = '')
1039	{
1040	$this->cachedir = $path;
1041	}
1042
1043	// --------------------------------------------------------------------
1044
1045	/**
1046	* Enable Query Caching
1047	*
1048	* @access public
1049	* @return void
1050	*/
1051	function cache_on()
1052	{
1053	$this->cache_on = TRUE;
1054	return TRUE;
1055	}
1056
1057	// --------------------------------------------------------------------
1058
1059	/**
1060	* Disable Query Caching
1061	*
1062	* @access public
1063	* @return void
1064	*/
1065	function cache_off()
1066	{
1067	$this->cache_on = FALSE;
1068	return FALSE;
1069	}
1070
1071
1072	// --------------------------------------------------------------------
1073
1074	/**
1075	* Delete the cache files associated with a particular URI
1076	*
1077	* @access public
1078	* @return void
1079	*/
1080	function cache_delete($segment_one = '', $segment_two = '')
1081	{
1082	if ( ! $this->_cache_init())
1083	{
1084	return FALSE;
1085	}
1086	return $this->CACHE->delete($segment_one, $segment_two);
1087	}
1088
1089	// --------------------------------------------------------------------
1090
1091	/**
1092	* Delete All cache files
1093	*
1094	* @access public
1095	* @return void
1096	*/
1097	function cache_delete_all()
1098	{
1099	if ( ! $this->_cache_init())
1100	{
1101	return FALSE;
1102	}
1103
1104	return $this->CACHE->delete_all();
1105	}
1106
1107	// --------------------------------------------------------------------
1108
1109	/**
1110	* Initialize the Cache Class
1111	*
1112	* @access private
1113	* @return void
1114	*/
1115	function _cache_init()
1116	{
1117	if (is_object($this->CACHE) AND class_exists('CI_DB_Cache'))
1118	{
1119	return TRUE;
1120	}
1121
1122	if ( ! class_exists('CI_DB_Cache'))
1123	{
1124	if ( ! @include(BASEPATH.'database/DB_cache.php'))
1125	{
1126	return $this->cache_off();
1127	}
1128	}
1129
1130	$this->CACHE = new CI_DB_Cache($this); // pass db object to support multiple db connections and returned db objects
1131	return TRUE;
1132	}
1133
1134	// --------------------------------------------------------------------
1135
1136	/**
1137	* Close DB Connection
1138	*
1139	* @access public
1140	* @return void
1141	*/
1142	function close()
1143	{
1144	if (is_resource($this->conn_id) OR is_object($this->conn_id))
1145	{
1146	$this->_close($this->conn_id);
1147	}
1148	$this->conn_id = FALSE;
1149	}
1150
1151	// --------------------------------------------------------------------
1152
1153	/**
1154	* Display an error message
1155	*
1156	* @access public
1157	* @param string the error message
1158	* @param string any "swap" values
1159	* @param boolean whether to localize the message
1160	* @return string sends the application/error_db.php template
1161	*/
1162	function display_error($error = '', $swap = '', $native = FALSE)
1163	{
1164	$LANG =& load_class('Lang', 'core');
1165	$LANG->load('db');
1166
1167	$heading = $LANG->line('db_error_heading');
1168
1169	if ($native == TRUE)
1170	{
1171	$message = $error;
1172	}
1173	else
1174	{
1175	$message = ( ! is_array($error)) ? array(str_replace('%s', $swap, $LANG->line($error))) : $error;
1176	}
1177
1178	// Find the most likely culprit of the error by going through
1179	// the backtrace until the source file is no longer in the
1180	// database folder.
1181
1182	$trace = debug_backtrace();
1183
1184	foreach ($trace as $call)
1185	{
1186	if (isset($call['file']) && strpos($call['file'], BASEPATH.'database') === FALSE)
1187	{
1188	// Found it - use a relative path for safety
1189	$message[] = 'Filename: '.str_replace(array(BASEPATH, APPPATH), '', $call['file']);
1190	$message[] = 'Line Number: '.$call['line'];
1191
1192	break;
1193	}
1194	}
1195
1196	$error =& load_class('Exceptions', 'core');
1197	echo $error->show_error($heading, $message, 'error_db');
1198	exit;
1199	}
1200
1201	// --------------------------------------------------------------------
1202
1203	/**
1204	* Protect Identifiers
1205	*
1206	* This function adds backticks if appropriate based on db type
1207	*
1208	* @access private
1209	* @param mixed the item to escape
1210	* @return mixed the item with backticks
1211	*/
1212	function protect_identifiers($item, $prefix_single = FALSE)
1213	{
1214	return $this->_protect_identifiers($item, $prefix_single);
1215	}
1216
1217	// --------------------------------------------------------------------
1218
1219	/**
1220	* Protect Identifiers
1221	*
1222	* This function is used extensively by the Active Record class, and by
1223	* a couple functions in this class.
1224	* It takes a column or table name (optionally with an alias) and inserts
1225	* the table prefix onto it. Some logic is necessary in order to deal with
1226	* column names that include the path. Consider a query like this:
1227	*
1228	* SELECT * FROM hostname.database.table.column AS c FROM hostname.database.table
1229	*
1230	* Or a query with aliasing:
1231	*
1232	* SELECT m.member_id, m.member_name FROM members AS m
1233	*
1234	* Since the column name can include up to four segments (host, DB, table, column)
1235	* or also have an alias prefix, we need to do a bit of work to figure this out and
1236	* insert the table prefix (if it exists) in the proper position, and escape only
1237	* the correct identifiers.
1238	*
1239	* @access private
1240	* @param string
1241	* @param bool
1242	* @param mixed
1243	* @param bool
1244	* @return string
1245	*/
1246	function _protect_identifiers($item, $prefix_single = FALSE, $protect_identifiers = NULL, $field_exists = TRUE)
1247	{
1248	if ( ! is_bool($protect_identifiers))
1249	{
1250	$protect_identifiers = $this->_protect_identifiers;
1251	}
1252
1253	if (is_array($item))
1254	{
1255	$escaped_array = array();
1256
1257	foreach ($item as $k => $v)
1258	{
1259	$escaped_array[$this->_protect_identifiers($k)] = $this->_protect_identifiers($v);
1260	}
1261
1262	return $escaped_array;
1263	}
1264
1265	// Convert tabs or multiple spaces into single spaces
1266	$item = preg_replace('/[\t ]+/', ' ', $item);
1267
1268	// If the item has an alias declaration we remove it and set it aside.
1269	// Basically we remove everything to the right of the first space
1270	if (strpos($item, ' ') !== FALSE)
1271	{
1272	$alias = strstr($item, ' ');
1273	$item = substr($item, 0, - strlen($alias));
1274	}
1275	else
1276	{
1277	$alias = '';
1278	}
1279
1280	// This is basically a bug fix for queries that use MAX, MIN, etc.
1281	// If a parenthesis is found we know that we do not need to
1282	// escape the data or add a prefix. There's probably a more graceful
1283	// way to deal with this, but I'm not thinking of it -- Rick
1284	if (strpos($item, '(') !== FALSE)
1285	{
1286	return $item.$alias;
1287	}
1288
1289	// Break the string apart if it contains periods, then insert the table prefix
1290	// in the correct location, assuming the period doesn't indicate that we're dealing
1291	// with an alias. While we're at it, we will escape the components
1292	if (strpos($item, '.') !== FALSE)
1293	{
1294	$parts = explode('.', $item);
1295
1296	// Does the first segment of the exploded item match
1297	// one of the aliases previously identified? If so,
1298	// we have nothing more to do other than escape the item
1299	if (in_array($parts[0], $this->ar_aliased_tables))
1300	{
1301	if ($protect_identifiers === TRUE)
1302	{
1303	foreach ($parts as $key => $val)
1304	{
1305	if ( ! in_array($val, $this->_reserved_identifiers))
1306	{
1307	$parts[$key] = $this->_escape_identifiers($val);
1308	}
1309	}
1310
1311	$item = implode('.', $parts);
1312	}
1313	return $item.$alias;
1314	}
1315
1316	// Is there a table prefix defined in the config file? If not, no need to do anything
1317	if ($this->dbprefix != '')
1318	{
1319	// We now add the table prefix based on some logic.
1320	// Do we have 4 segments (hostname.database.table.column)?
1321	// If so, we add the table prefix to the column name in the 3rd segment.
1322	if (isset($parts[3]))
1323	{
1324	$i = 2;
1325	}
1326	// Do we have 3 segments (database.table.column)?
1327	// If so, we add the table prefix to the column name in 2nd position
1328	elseif (isset($parts[2]))
1329	{
1330	$i = 1;
1331	}
1332	// Do we have 2 segments (table.column)?
1333	// If so, we add the table prefix to the column name in 1st segment
1334	else
1335	{
1336	$i = 0;
1337	}
1338
1339	// This flag is set when the supplied $item does not contain a field name.
1340	// This can happen when this function is being called from a JOIN.
1341	if ($field_exists == FALSE)
1342	{
1343	$i++;
1344	}
1345
1346	// Verify table prefix and replace if necessary
1347	if ($this->swap_pre != '' && strncmp($parts[$i], $this->swap_pre, strlen($this->swap_pre)) === 0)
1348	{
1349	$parts[$i] = preg_replace("/^".$this->swap_pre."(\S+?)/", $this->dbprefix."\\1", $parts[$i]);
1350	}
1351
1352	// We only add the table prefix if it does not already exist
1353	if (substr($parts[$i], 0, strlen($this->dbprefix)) != $this->dbprefix)
1354	{
1355	$parts[$i] = $this->dbprefix.$parts[$i];
1356	}
1357
1358	// Put the parts back together
1359	$item = implode('.', $parts);
1360	}
1361
1362	if ($protect_identifiers === TRUE)
1363	{
1364	$item = $this->_escape_identifiers($item);
1365	}
1366
1367	return $item.$alias;
1368	}
1369
1370	// Is there a table prefix? If not, no need to insert it
1371	if ($this->dbprefix != '')
1372	{
1373	// Verify table prefix and replace if necessary
1374	if ($this->swap_pre != '' && strncmp($item, $this->swap_pre, strlen($this->swap_pre)) === 0)
1375	{
1376	$item = preg_replace("/^".$this->swap_pre."(\S+?)/", $this->dbprefix."\\1", $item);
1377	}
1378
1379	// Do we prefix an item with no segments?
1380	if ($prefix_single == TRUE AND substr($item, 0, strlen($this->dbprefix)) != $this->dbprefix)
1381	{
1382	$item = $this->dbprefix.$item;
1383	}
1384	}
1385
1386	if ($protect_identifiers === TRUE AND ! in_array($item, $this->_reserved_identifiers))
1387	{
1388	$item = $this->_escape_identifiers($item);
1389	}
1390
1391	return $item.$alias;
1392	}
1393
1394	// --------------------------------------------------------------------
1395
1396	/**
1397	* Dummy method that allows Active Record class to be disabled
1398	*
1399	* This function is used extensively by every db driver.
1400	*
1401	* @return void
1402	*/
1403	protected function _reset_select()
1404	{
1405	}
1406
1407	}
1408
1409	/* End of file DB_driver.php */
1410	/* Location: ./system/database/DB_driver.php */

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