joomla-framework /src/Joomla/Database/DatabaseDriver.php

Language PHP Lines 1696
MD5 Hash 462f5fdaf6787db9a50c98f244bedb69 Estimated Cost $17,159 (why?)
Repository https://github.com/piotr-cz/joomla-framework.git View Raw File
   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
<?php
/**
 * Part of the Joomla Framework Database Package
 *
 * @copyright  Copyright (C) 2005 - 2013 Open Source Matters, Inc. All rights reserved.
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\Database;

use Psr\Log;

/**
 * Joomla Framework Database Driver Class
 *
 * @since  1.0
 *
 * @method  string  q()   q($text, $escape = true)  Alias for quote method
 * @method  string  qn()  qn($name, $as = null)     Alias for quoteName method
 */
abstract class DatabaseDriver implements DatabaseInterface, Log\LoggerAwareInterface
{
	/**
	 * The name of the database.
	 *
	 * @var    string
	 * @since  1.0
	 */
	private $database;

	/**
	 * The name of the database driver.
	 *
	 * @var    string
	 * @since  1.0
	 */
	public $name;

	/**
	 * The database connection resource.
	 *
	 * @var    resource
	 * @since  1.0
	 */
	protected $connection;

	/**
	 * Holds the list of available db connectors.
	 *
	 * @var    array
	 * @since  1.0
	 */
	protected static $connectors;

	/**
	 * The number of SQL statements executed by the database driver.
	 *
	 * @var    integer
	 * @since  1.0
	 */
	protected $count = 0;

	/**
	 * The database connection cursor from the last query.
	 *
	 * @var    resource
	 * @since  1.0
	 */
	protected $cursor;

	/**
	 * The database driver debugging state.
	 *
	 * @var    boolean
	 * @since  1.0
	 */
	protected $debug = false;

	/**
	 * The affected row limit for the current SQL statement.
	 *
	 * @var    integer
	 * @since  1.0
	 */
	protected $limit = 0;

	/**
	 * The character(s) used to quote SQL statement names such as table names or field names,
	 * etc.
	 *
	 * The child classes should define this as necessary.  If a single character string the
	 * same character is used for both sides of the quoted name, else the first character will be
	 * used for the opening quote and the second for the closing quote.
	 *
	 * @var    string
	 * @since  1.0
	 */
	protected $nameQuote;

	/**
	 * The null or zero representation of a timestamp for the database driver.
	 *
	 * This should be defined in child classes to hold the appropriate value for the engine.
	 *
	 * @var    string
	 * @since  1.0
	 */
	protected $nullDate;

	/**
	 * The affected row offset to apply for the current SQL statement.
	 *
	 * @var    integer
	 * @since  1.0
	 */
	protected $offset = 0;

	/**
	 * Passed in upon instantiation and saved.
	 *
	 * @var    array
	 * @since  1.0
	 */
	protected $options;

	/**
	 * The current SQL statement to execute.
	 *
	 * @var    mixed
	 * @since  1.0
	 */
	protected $sql;

	/**
	 * The common database table prefix.
	 *
	 * @var    string
	 * @since  1.0
	 */
	protected $tablePrefix;

	/**
	 * True if the database engine supports UTF-8 character encoding.
	 *
	 * @var    boolean
	 * @since  1.0
	 */
	protected $utf = true;

	/**
	 * The database error number.
	 *
	 * @var    integer
	 * @since  1.0
	 */
	protected $errorNum = 0;

	/**
	 * The database error message.
	 *
	 * @var    string
	 * @since  1.0
	 */
	protected $errorMsg;

	/**
	 * DatabaseDriver instances container.
	 *
	 * @var    array
	 * @since  1.0
	 */
	protected static $instances = array();

	/**
	 * The minimum supported database version.
	 *
	 * @var    string
	 * @since  1.0
	 */
	protected static $dbMinimum;

	/**
	 * The depth of the current transaction.
	 *
	 * @var    integer
	 * @since  1.0
	 */
	protected $transactionDepth = 0;

	/**
	 * A logger.
	 *
	 * @var    Log\LoggerInterface
	 * @since  1.0
	 */
	private $logger;

	/**
	 * Get a list of available database connectors.  The list will only be populated with connectors that both
	 * the class exists and the static test method returns true.  This gives us the ability to have a multitude
	 * of connector classes that are self-aware as to whether or not they are able to be used on a given system.
	 *
	 * @return  array  An array of available database connectors.
	 *
	 * @since   1.0
	 */
	public static function getConnectors()
	{
		if (!isset(self::$connectors))
		{
			self::$connectors = array();

			// Get an iterator and loop trough the driver classes.
			$dir = __DIR__;
			$iterator = new \DirectoryIterator($dir);

			/* @var  $file  \DirectoryIterator */
			foreach ($iterator as $file)
			{
				// Only load for php files.
				if (!$file->isDir())
				{
					continue;
				}

				$baseName = $file->getBasename();

				// Derive the class name from the type.
				/* @var  $class  DatabaseDriver */
				$class = '\\Joomla\\Database\\' . ucfirst(strtolower($baseName)) . '\\' . ucfirst(strtolower($baseName)) . 'Driver';

				// If the class doesn't exist, or if it's not supported on this system, move on to the next type.
				if (!class_exists($class) || !($class::isSupported()))
				{
					continue;
				}

				// Everything looks good, add it to the list.
				self::$connectors[] = $baseName;
			}
		}

		return self::$connectors;
	}

	/**
	 * Method to return a Driver instance based on the given options.  There are three global options and then
	 * the rest are specific to the database driver.  The 'driver' option defines which Driver class is
	 * used for the connection -- the default is 'mysqli'.  The 'database' option determines which database is to
	 * be used for the connection.  The 'select' option determines whether the connector should automatically select
	 * the chosen database.
	 *
	 * Instances are unique to the given options and new objects are only created when a unique options array is
	 * passed into the method.  This ensures that we don't end up with unnecessary database connection resources.
	 *
	 * @param   array  $options  Parameters to be passed to the database driver.
	 *
	 * @return  DatabaseDriver  A database object.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public static function getInstance($options = array())
	{
		// Sanitize the database connector options.
		$options['driver']   = (isset($options['driver'])) ? preg_replace('/[^A-Z0-9_\.-]/i', '', $options['driver']) : 'mysqli';
		$options['database'] = (isset($options['database'])) ? $options['database'] : null;
		$options['select']   = (isset($options['select'])) ? $options['select'] : true;

		// Get the options signature for the database connector.
		$signature = md5(serialize($options));

		// If we already have a database connector instance for these options then just use that.
		if (empty(self::$instances[$signature]))
		{
			// Derive the class name from the driver.
			$class = '\\Joomla\\Database\\' . ucfirst(strtolower($options['driver'])) . '\\' . ucfirst(strtolower($options['driver'])) . 'Driver';

			// If the class still doesn't exist we have nothing left to do but throw an exception.  We did our best.
			if (!class_exists($class))
			{
				throw new \RuntimeException(sprintf('Unable to load Database Driver: %s', $options['driver']));
			}

			// Create our new Driver connector based on the options given.
			try
			{
				$instance = new $class($options);
			}
			catch (\RuntimeException $e)
			{
				throw new \RuntimeException(sprintf('Unable to connect to the Database: %s', $e->getMessage()));
			}

			// Set the new connector to the global instances based on signature.
			self::$instances[$signature] = $instance;
		}

		return self::$instances[$signature];
	}

	/**
	 * Splits a string of multiple queries into an array of individual queries.
	 *
	 * @param   string  $sql  Input SQL string with which to split into individual queries.
	 *
	 * @return  array  The queries from the input string separated into an array.
	 *
	 * @since   1.0
	 */
	public static function splitSql($sql)
	{
		$start = 0;
		$open = false;
		$char = '';
		$end = strlen($sql);
		$queries = array();

		for ($i = 0; $i < $end; $i++)
		{
			$current = substr($sql, $i, 1);

			if (($current == '"' || $current == '\''))
			{
				$n = 2;

				while (substr($sql, $i - $n + 1, 1) == '\\' && $n < $i)
				{
					$n++;
				}

				if ($n % 2 == 0)
				{
					if ($open)
					{
						if ($current == $char)
						{
							$open = false;
							$char = '';
						}
					}
					else
					{
						$open = true;
						$char = $current;
					}
				}
			}

			if (($current == ';' && !$open) || $i == $end - 1)
			{
				$queries[] = substr($sql, $start, ($i - $start + 1));
				$start = $i + 1;
			}
		}

		return $queries;
	}

	/**
	 * Magic method to provide method alias support for quote() and quoteName().
	 *
	 * @param   string  $method  The called method.
	 * @param   array   $args    The array of arguments passed to the method.
	 *
	 * @return  string  The aliased method's return value or null.
	 *
	 * @since   1.0
	 */
	public function __call($method, $args)
	{
		if (empty($args))
		{
			return;
		}

		switch ($method)
		{
			case 'q':
				return $this->quote($args[0], isset($args[1]) ? $args[1] : true);
				break;

			case 'qn':
				return $this->quoteName($args[0], isset($args[1]) ? $args[1] : null);
				break;
		}
	}

	/**
	 * Constructor.
	 *
	 * @param   array  $options  List of options used to configure the connection
	 *
	 * @since   1.0
	 */
	public function __construct($options)
	{
		// Initialise object variables.
		$this->database = (isset($options['database'])) ? $options['database'] : '';

		$this->tablePrefix = (isset($options['prefix'])) ? $options['prefix'] : 'jos_';
		$this->count = 0;
		$this->errorNum = 0;

		// Set class options.
		$this->options = $options;
	}

	/**
	 * Connects to the database if needed.
	 *
	 * @return  void  Returns void if the database connected successfully.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function connect();

	/**
	 * Determines if the connection to the server is active.
	 *
	 * @return  boolean  True if connected to the database engine.
	 *
	 * @since   1.0
	 */
	abstract public function connected();

	/**
	 * Disconnects the database.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 */
	abstract public function disconnect();

	/**
	 * Drops a table from the database.
	 *
	 * @param   string   $table     The name of the database table to drop.
	 * @param   boolean  $ifExists  Optionally specify that the table must exist before it is dropped.
	 *
	 * @return  DatabaseDriver  Returns this object to support chaining.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function dropTable($table, $ifExists = true);

	/**
	 * Escapes a string for usage in an SQL statement.
	 *
	 * @param   string   $text   The string to be escaped.
	 * @param   boolean  $extra  Optional parameter to provide extra escaping.
	 *
	 * @return  string   The escaped string.
	 *
	 * @since   1.0
	 */
	abstract public function escape($text, $extra = false);

	/**
	 * Method to fetch a row from the result set cursor as an array.
	 *
	 * @param   mixed  $cursor  The optional result set cursor from which to fetch the row.
	 *
	 * @return  mixed  Either the next row from the result set or false if there are no more rows.
	 *
	 * @since   1.0
	 */
	abstract protected function fetchArray($cursor = null);

	/**
	 * Method to fetch a row from the result set cursor as an associative array.
	 *
	 * @param   mixed  $cursor  The optional result set cursor from which to fetch the row.
	 *
	 * @return  mixed  Either the next row from the result set or false if there are no more rows.
	 *
	 * @since   1.0
	 */
	abstract protected function fetchAssoc($cursor = null);

	/**
	 * Method to fetch a row from the result set cursor as an object.
	 *
	 * @param   mixed   $cursor  The optional result set cursor from which to fetch the row.
	 * @param   string  $class   The class name to use for the returned row object.
	 *
	 * @return  mixed   Either the next row from the result set or false if there are no more rows.
	 *
	 * @since   1.0
	 */
	abstract protected function fetchObject($cursor = null, $class = 'stdClass');

	/**
	 * Method to free up the memory used for the result set.
	 *
	 * @param   mixed  $cursor  The optional result set cursor from which to fetch the row.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 */
	abstract protected function freeResult($cursor = null);

	/**
	 * Get the number of affected rows for the previous executed SQL statement.
	 *
	 * @return  integer  The number of affected rows.
	 *
	 * @since   1.0
	 */
	abstract public function getAffectedRows();

	/**
	 * Method to get the database collation in use by sampling a text field of a table in the database.
	 *
	 * @return  mixed  The collation in use by the database or boolean false if not supported.
	 *
	 * @since   1.0
	 */
	abstract public function getCollation();

	/**
	 * Method that provides access to the underlying database connection. Useful for when you need to call a
	 * proprietary method such as PostgreSQL's lo_* methods.
	 *
	 * @return  resource  The underlying database connection resource.
	 *
	 * @since   1.0
	 */
	public function getConnection()
	{
		return $this->connection;
	}

	/**
	 * Get the total number of SQL statements executed by the database driver.
	 *
	 * @return  integer
	 *
	 * @since   1.0
	 */
	public function getCount()
	{
		return $this->count;
	}

	/**
	 * Gets the name of the database used by this conneciton.
	 *
	 * @return  string
	 *
	 * @since   1.0
	 */
	protected function getDatabase()
	{
		return $this->database;
	}

	/**
	 * Returns a PHP date() function compliant date format for the database driver.
	 *
	 * @return  string  The format string.
	 *
	 * @since   1.0
	 */
	public function getDateFormat()
	{
		return 'Y-m-d H:i:s';
	}

	/**
	 * Get the minimum supported database version.
	 *
	 * @return  string  The minimum version number for the database driver.
	 *
	 * @since   1.0
	 */
	public function getMinimum()
	{
		return static::$dbMinimum;
	}

	/**
	 * Get the null or zero representation of a timestamp for the database driver.
	 *
	 * @return  string  Null or zero representation of a timestamp.
	 *
	 * @since   1.0
	 */
	public function getNullDate()
	{
		return $this->nullDate;
	}

	/**
	 * Get the number of returned rows for the previous executed SQL statement.
	 *
	 * @param   resource  $cursor  An optional database cursor resource to extract the row count from.
	 *
	 * @return  integer   The number of returned rows.
	 *
	 * @since   1.0
	 */
	abstract public function getNumRows($cursor = null);

	/**
	 * Get the common table prefix for the database driver.
	 *
	 * @return  string  The common database table prefix.
	 *
	 * @since   1.0
	 */
	public function getPrefix()
	{
		return $this->tablePrefix;
	}

	/**
	 * Gets an exporter class object.
	 *
	 * @return  DatabaseExporter  An exporter object.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function getExporter()
	{
		// Derive the class name from the driver.
		$class = '\\Joomla\\Database\\' . ucfirst($this->name) . '\\' . ucfirst($this->name) . 'Exporter';

		// Make sure we have an exporter class for this driver.
		if (!class_exists($class))
		{
			// If it doesn't exist we are at an impasse so throw an exception.
			throw new \RuntimeException('Database Exporter not found.');
		}

		/* @var  $o  DatabaseExporter */
		$o = new $class;
		$o->setDbo($this);

		return $o;
	}

	/**
	 * Gets an importer class object.
	 *
	 * @return  DatabaseImporter  An importer object.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function getImporter()
	{
		// Derive the class name from the driver.
		$class = '\\Joomla\\Database\\' . ucfirst($this->name) . '\\' . ucfirst($this->name) . 'Importer';

		// Make sure we have an importer class for this driver.
		if (!class_exists($class))
		{
			// If it doesn't exist we are at an impasse so throw an exception.
			throw new \RuntimeException('Database Importer not found');
		}

		/* @var  $o  DatabaseImporter */
		$o = new $class;
		$o->setDbo($this);

		return $o;
	}

	/**
	 * Get the current query object or a new Query object.
	 *
	 * @param   boolean  $new  False to return the current query object, True to return a new Query object.
	 *
	 * @return  DatabaseQuery  The current query object or a new object extending the Query class.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function getQuery($new = false)
	{
		if ($new)
		{
			// Derive the class name from the driver.
			$class = '\\Joomla\\Database\\' . ucfirst($this->name) . '\\' . ucfirst($this->name) . 'Query';

			// Make sure we have a query class for this driver.
			if (!class_exists($class))
			{
				// If it doesn't exist we are at an impasse so throw an exception.
				throw new \RuntimeException('Database Query Class not found.');
			}

			return new $class($this);
		}
		else
		{
			return $this->sql;
		}
	}

	/**
	 * Get a new iterator on the current query.
	 *
	 * @param   string  $column  An option column to use as the iterator key.
	 * @param   string  $class   The class of object that is returned.
	 *
	 * @return  DatabaseIterator  A new database iterator.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function getIterator($column = null, $class = '\\stdClass')
	{
		// Derive the class name from the driver.
		$iteratorClass = '\\Joomla\\Database\\' . ucfirst($this->name) . '\\' . ucfirst($this->name) . 'Iterator';

		// Make sure we have an iterator class for this driver.
		if (!class_exists($iteratorClass))
		{
			// If it doesn't exist we are at an impasse so throw an exception.
			throw new \RuntimeException(sprintf('class *%s* is not defined', $iteratorClass));
		}

		// Return a new iterator
		return new $iteratorClass($this->execute(), $column, $class);
	}

	/**
	 * Retrieves field information about the given tables.
	 *
	 * @param   string   $table     The name of the database table.
	 * @param   boolean  $typeOnly  True (default) to only return field types.
	 *
	 * @return  array  An array of fields by table.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function getTableColumns($table, $typeOnly = true);

	/**
	 * Shows the table CREATE statement that creates the given tables.
	 *
	 * @param   mixed  $tables  A table name or a list of table names.
	 *
	 * @return  array  A list of the create SQL for the tables.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function getTableCreate($tables);

	/**
	 * Retrieves field information about the given tables.
	 *
	 * @param   mixed  $tables  A table name or a list of table names.
	 *
	 * @return  array  An array of keys for the table(s).
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function getTableKeys($tables);

	/**
	 * Method to get an array of all tables in the database.
	 *
	 * @return  array  An array of all the tables in the database.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function getTableList();

	/**
	 * Determine whether or not the database engine supports UTF-8 character encoding.
	 *
	 * @return  boolean  True if the database engine supports UTF-8 character encoding.
	 *
	 * @since   1.0
	 */
	public function hasUTFSupport()
	{
		return $this->utf;
	}

	/**
	 * Get the version of the database connector
	 *
	 * @return  string  The database connector version.
	 *
	 * @since   1.0
	 */
	abstract public function getVersion();

	/**
	 * Method to get the auto-incremented value from the last INSERT statement.
	 *
	 * @return  mixed  The value of the auto-increment field from the last inserted row.
	 *
	 * @since   1.0
	 */
	abstract public function insertid();

	/**
	 * Inserts a row into a table based on an object's properties.
	 *
	 * @param   string  $table    The name of the database table to insert into.
	 * @param   object  &$object  A reference to an object whose public properties match the table fields.
	 * @param   string  $key      The name of the primary key. If provided the object property is updated.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function insertObject($table, &$object, $key = null)
	{
		$fields = array();
		$values = array();

		// Iterate over the object variables to build the query fields and values.
		foreach (get_object_vars($object) as $k => $v)
		{
			// Only process non-null scalars.
			if (is_array($v) or is_object($v) or $v === null)
			{
				continue;
			}

			// Ignore any internal fields.
			if ($k[0] == '_')
			{
				continue;
			}

			// Prepare and sanitize the fields and values for the database query.
			$fields[] = $this->quoteName($k);
			$values[] = $this->quote($v);
		}

		// Create the base insert statement.
		$query = $this->getQuery(true);
		$query->insert($this->quoteName($table))
			->columns($fields)
			->values(implode(',', $values));

		// Set the query and execute the insert.
		$this->setQuery($query);

		if (!$this->execute())
		{
			return false;
		}

		// Update the primary key if it exists.
		$id = $this->insertid();

		if ($key && $id && is_string($key))
		{
			$object->$key = $id;
		}

		return true;
	}

	/**
	 * Method to check whether the installed database version is supported by the database driver
	 *
	 * @return  boolean  True if the database version is supported
	 *
	 * @since   1.0
	 */
	public function isMinimumVersion()
	{
		return version_compare($this->getVersion(), static::$dbMinimum) >= 0;
	}

	/**
	 * Method to get the first row of the result set from the database query as an associative array
	 * of ['field_name' => 'row_value'].
	 *
	 * @return  mixed  The return value or null if the query failed.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function loadAssoc()
	{
		$this->connect();

		$ret = null;

		// Execute the query and get the result set cursor.
		if (!($cursor = $this->execute()))
		{
			return null;
		}

		// Get the first row from the result set as an associative array.
		$array = $this->fetchAssoc($cursor);

		if ($array)
		{
			$ret = $array;
		}

		// Free up system resources and return.
		$this->freeResult($cursor);

		return $ret;
	}

	/**
	 * Method to get an array of the result set rows from the database query where each row is an associative array
	 * of ['field_name' => 'row_value'].  The array of rows can optionally be keyed by a field name, but defaults to
	 * a sequential numeric array.
	 *
	 * NOTE: Chosing to key the result array by a non-unique field name can result in unwanted
	 * behavior and should be avoided.
	 *
	 * @param   string  $key     The name of a field on which to key the result array.
	 * @param   string  $column  An optional column name. Instead of the whole row, only this column value will be in
	 *                           the result array.
	 *
	 * @return  mixed   The return value or null if the query failed.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function loadAssocList($key = null, $column = null)
	{
		$this->connect();

		$array = array();

		// Execute the query and get the result set cursor.
		if (!($cursor = $this->execute()))
		{
			return null;
		}

		// Get all of the rows from the result set.
		while ($row = $this->fetchAssoc($cursor))
		{
			$value = ($column) ? (isset($row[$column]) ? $row[$column] : $row) : $row;

			if ($key)
			{
				$array[$row[$key]] = $value;
			}
			else
			{
				$array[] = $value;
			}
		}

		// Free up system resources and return.
		$this->freeResult($cursor);

		return $array;
	}

	/**
	 * Method to get an array of values from the <var>$offset</var> field in each row of the result set from
	 * the database query.
	 *
	 * @param   integer  $offset  The row offset to use to build the result array.
	 *
	 * @return  mixed  The return value or null if the query failed.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function loadColumn($offset = 0)
	{
		$this->connect();

		$array = array();

		// Execute the query and get the result set cursor.
		if (!($cursor = $this->execute()))
		{
			return null;
		}

		// Get all of the rows from the result set as arrays.
		while ($row = $this->fetchArray($cursor))
		{
			$array[] = $row[$offset];
		}

		// Free up system resources and return.
		$this->freeResult($cursor);

		return $array;
	}

	/**
	 * Method to get the first row of the result set from the database query as an object.
	 *
	 * @param   string  $class  The class name to use for the returned row object.
	 *
	 * @return  mixed  The return value or null if the query failed.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function loadObject($class = 'stdClass')
	{
		$this->connect();

		$ret = null;

		// Execute the query and get the result set cursor.
		if (!($cursor = $this->execute()))
		{
			return null;
		}

		// Get the first row from the result set as an object of type $class.
		$object = $this->fetchObject($cursor, $class);

		if ($object)
		{
			$ret = $object;
		}

		// Free up system resources and return.
		$this->freeResult($cursor);

		return $ret;
	}

	/**
	 * Method to get an array of the result set rows from the database query where each row is an object.  The array
	 * of objects can optionally be keyed by a field name, but defaults to a sequential numeric array.
	 *
	 * NOTE: Choosing to key the result array by a non-unique field name can result in unwanted
	 * behavior and should be avoided.
	 *
	 * @param   string  $key    The name of a field on which to key the result array.
	 * @param   string  $class  The class name to use for the returned row objects.
	 *
	 * @return  mixed  The return value or null if the query failed.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function loadObjectList($key = '', $class = 'stdClass')
	{
		$this->connect();

		$array = array();

		// Execute the query and get the result set cursor.
		if (!($cursor = $this->execute()))
		{
			return null;
		}

		// Get all of the rows from the result set as objects of type $class.
		while ($row = $this->fetchObject($cursor, $class))
		{
			if ($key)
			{
				$array[$row->$key] = $row;
			}
			else
			{
				$array[] = $row;
			}
		}

		// Free up system resources and return.
		$this->freeResult($cursor);

		return $array;
	}

	/**
	 * Method to get the first field of the first row of the result set from the database query.
	 *
	 * @return  mixed  The return value or null if the query failed.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function loadResult()
	{
		$this->connect();

		$ret = null;

		// Execute the query and get the result set cursor.
		if (!($cursor = $this->execute()))
		{
			return null;
		}

		// Get the first row from the result set as an array.
		$row = $this->fetchArray($cursor);

		if ($row)
		{
			$ret = $row[0];
		}

		// Free up system resources and return.
		$this->freeResult($cursor);

		return $ret;
	}

	/**
	 * Method to get the first row of the result set from the database query as an array.  Columns are indexed
	 * numerically so the first column in the result set would be accessible via <var>$row[0]</var>, etc.
	 *
	 * @return  mixed  The return value or null if the query failed.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function loadRow()
	{
		$this->connect();

		$ret = null;

		// Execute the query and get the result set cursor.
		if (!($cursor = $this->execute()))
		{
			return null;
		}

		// Get the first row from the result set as an array.
		$row = $this->fetchArray($cursor);

		if ($row)
		{
			$ret = $row;
		}

		// Free up system resources and return.
		$this->freeResult($cursor);

		return $ret;
	}

	/**
	 * Method to get an array of the result set rows from the database query where each row is an array.  The array
	 * of objects can optionally be keyed by a field offset, but defaults to a sequential numeric array.
	 *
	 * NOTE: Choosing to key the result array by a non-unique field can result in unwanted
	 * behavior and should be avoided.
	 *
	 * @param   string  $key  The name of a field on which to key the result array.
	 *
	 * @return  mixed   The return value or null if the query failed.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function loadRowList($key = null)
	{
		$this->connect();

		$array = array();

		// Execute the query and get the result set cursor.
		if (!($cursor = $this->execute()))
		{
			return null;
		}

		// Get all of the rows from the result set as arrays.
		while ($row = $this->fetchArray($cursor))
		{
			if ($key !== null)
			{
				$array[$row[$key]] = $row;
			}
			else
			{
				$array[] = $row;
			}
		}

		// Free up system resources and return.
		$this->freeResult($cursor);

		return $array;
	}

	/**
	 * Logs a message.
	 *
	 * @param   string  $level    The level for the log. Use constants belonging to Psr\Log\LogLevel.
	 * @param   string  $message  The message.
	 * @param   array   $context  Additional context.
	 *
	 * @return  DatabaseDriver  Returns itself to allow chaining.
	 *
	 * @since   1.0
	 */
	public function log($level, $message, array $context = array())
	{
		if ($this->logger)
		{
			$this->logger->log($level, $message, $context);
		}

		return $this;
	}

	/**
	 * Locks a table in the database.
	 *
	 * @param   string  $tableName  The name of the table to unlock.
	 *
	 * @return  DatabaseDriver  Returns this object to support chaining.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function lockTable($tableName);

	/**
	 * Quotes and optionally escapes a string to database requirements for use in database queries.
	 *
	 * @param   mixed    $text    A string or an array of strings to quote.
	 * @param   boolean  $escape  True (default) to escape the string, false to leave it unchanged.
	 *
	 * @return  string  The quoted input string.
	 *
	 * @note    Accepting an array of strings was added in Platform 12.3.
	 * @since   1.0
	 */
	public function quote($text, $escape = true)
	{
		if (is_array($text))
		{
			foreach ($text as $k => $v)
			{
				$text[$k] = $this->quote($v, $escape);
			}

			return $text;
		}
		else
		{
			return '\'' . ($escape ? $this->escape($text) : $text) . '\'';
		}
	}

	/**
	 * Wrap an SQL statement identifier name such as column, table or database names in quotes to prevent injection
	 * risks and reserved word conflicts.
	 *
	 * @param   mixed  $name  The identifier name to wrap in quotes, or an array of identifier names to wrap in quotes.
	 *                        Each type supports dot-notation name.
	 * @param   mixed  $as    The AS query part associated to $name. It can be string or array, in latter case it has to be
	 *                        same length of $name; if is null there will not be any AS part for string or array element.
	 *
	 * @return  mixed  The quote wrapped name, same type of $name.
	 *
	 * @since   1.0
	 */
	public function quoteName($name, $as = null)
	{
		if (is_string($name))
		{
			$quotedName = $this->quoteNameStr(explode('.', $name));

			$quotedAs = '';

			if (!is_null($as))
			{
				settype($as, 'array');
				$quotedAs .= ' AS ' . $this->quoteNameStr($as);
			}

			return $quotedName . $quotedAs;
		}
		else
		{
			$fin = array();

			if (is_null($as))
			{
				foreach ($name as $str)
				{
					$fin[] = $this->quoteName($str);
				}
			}
			elseif (is_array($name) && (count($name) == count($as)))
			{
				$count = count($name);

				for ($i = 0; $i < $count; $i++)
				{
					$fin[] = $this->quoteName($name[$i], $as[$i]);
				}
			}

			return $fin;
		}
	}

	/**
	 * Quote strings coming from quoteName call.
	 *
	 * @param   array  $strArr  Array of strings coming from quoteName dot-explosion.
	 *
	 * @return  string  Dot-imploded string of quoted parts.
	 *
	 * @since   1.0
	 */
	protected function quoteNameStr($strArr)
	{
		$parts = array();
		$q = $this->nameQuote;

		foreach ($strArr as $part)
		{
			if (is_null($part))
			{
				continue;
			}

			if (strlen($q) == 1)
			{
				$parts[] = $q . $part . $q;
			}
			else
			{
				$parts[] = $q{0} . $part . $q{1};
			}
		}

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

	/**
	 * This function replaces a string identifier <var>$prefix</var> with the string held is the
	 * <var>tablePrefix</var> class variable.
	 *
	 * @param   string  $sql     The SQL statement to prepare.
	 * @param   string  $prefix  The common table prefix.
	 *
	 * @return  string  The processed SQL statement.
	 *
	 * @since   1.0
	 */
	public function replacePrefix($sql, $prefix = '#__')
	{
		$escaped = false;
		$startPos = 0;
		$quoteChar = '';
		$literal = '';

		$sql = trim($sql);
		$n = strlen($sql);

		while ($startPos < $n)
		{
			$ip = strpos($sql, $prefix, $startPos);

			if ($ip === false)
			{
				break;
			}

			$j = strpos($sql, "'", $startPos);
			$k = strpos($sql, '"', $startPos);

			if (($k !== false) && (($k < $j) || ($j === false)))
			{
				$quoteChar = '"';
				$j = $k;
			}
			else
			{
				$quoteChar = "'";
			}

			if ($j === false)
			{
				$j = $n;
			}

			$literal .= str_replace($prefix, $this->tablePrefix, substr($sql, $startPos, $j - $startPos));
			$startPos = $j;

			$j = $startPos + 1;

			if ($j >= $n)
			{
				break;
			}

			// Quote comes first, find end of quote
			while (true)
			{
				$k = strpos($sql, $quoteChar, $j);
				$escaped = false;

				if ($k === false)
				{
					break;
				}

				$l = $k - 1;

				while ($l >= 0 && $sql{$l} == '\\')
				{
					$l--;
					$escaped = !$escaped;
				}

				if ($escaped)
				{
					$j = $k + 1;
					continue;
				}

				break;
			}

			if ($k === false)
			{
				// Error in the query - no end quote; ignore it
				break;
			}

			$literal .= substr($sql, $startPos, $k - $startPos + 1);
			$startPos = $k + 1;
		}

		if ($startPos < $n)
		{
			$literal .= substr($sql, $startPos, $n - $startPos);
		}

		return $literal;
	}

	/**
	 * Renames a table in the database.
	 *
	 * @param   string  $oldTable  The name of the table to be renamed
	 * @param   string  $newTable  The new name for the table.
	 * @param   string  $backup    Table prefix
	 * @param   string  $prefix    For the table - used to rename constraints in non-mysql databases
	 *
	 * @return  DatabaseDriver  Returns this object to support chaining.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function renameTable($oldTable, $newTable, $backup = null, $prefix = null);

	/**
	 * Select a database for use.
	 *
	 * @param   string  $database  The name of the database to select for use.
	 *
	 * @return  boolean  True if the database was successfully selected.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function select($database);

	/**
	 * Sets the database debugging state for the driver.
	 *
	 * @param   boolean  $level  True to enable debugging.
	 *
	 * @return  boolean  The old debugging level.
	 *
	 * @since   1.0
	 */
	public function setDebug($level)
	{
		$previous = $this->debug;
		$this->debug = (bool) $level;

		return $previous;
	}

	/**
	 * Sets the SQL statement string for later execution.
	 *
	 * @param   mixed    $query   The SQL statement to set either as a Query object or a string.
	 * @param   integer  $offset  The affected row offset to set.
	 * @param   integer  $limit   The maximum affected rows to set.
	 *
	 * @return  DatabaseDriver  This object to support method chaining.
	 *
	 * @since   1.0
	 */
	public function setQuery($query, $offset = 0, $limit = 0)
	{
		$this->sql = $query;
		$this->limit = (int) max(0, $limit);
		$this->offset = (int) max(0, $offset);

		return $this;
	}

	/**
	 * Sets a logger instance on the object
	 *
	 * @param   Log\LoggerInterface  $logger  A PSR-3 compliant logger.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 */
	public function setLogger(Log\LoggerInterface $logger)
	{
		$this->logger = $logger;
	}

	/**
	 * Set the connection to use UTF-8 character encoding.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   1.0
	 */
	abstract public function setUTF();

	/**
	 * Method to commit a transaction.
	 *
	 * @param   boolean  $toSavepoint  If true, commit to the last savepoint.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function transactionCommit($toSavepoint = false);

	/**
	 * Method to roll back a transaction.
	 *
	 * @param   boolean  $toSavepoint  If true, rollback to the last savepoint.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function transactionRollback($toSavepoint = false);

	/**
	 * Method to initialize a transaction.
	 *
	 * @param   boolean  $asSavepoint  If true and a transaction is already active, a savepoint will be created.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function transactionStart($asSavepoint = false);

	/**
	 * Method to truncate a table.
	 *
	 * @param   string  $table  The table to truncate
	 *
	 * @return  void
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function truncateTable($table)
	{
		$this->setQuery('TRUNCATE TABLE ' . $this->quoteName($table));
		$this->execute();
	}

	/**
	 * Updates a row in a table based on an object's properties.
	 *
	 * @param   string   $table    The name of the database table to update.
	 * @param   object   &$object  A reference to an object whose public properties match the table fields.
	 * @param   array    $key      The name of the primary key.
	 * @param   boolean  $nulls    True to update null fields or false to ignore them.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public function updateObject($table, &$object, $key, $nulls = false)
	{
		$fields = array();
		$where = array();

		if (is_string($key))
		{
			$key = array($key);
		}

		if (is_object($key))
		{
			$key = (array) $key;
		}

		// Create the base update statement.
		$statement = 'UPDATE ' . $this->quoteName($table) . ' SET %s WHERE %s';

		// Iterate over the object variables to build the query fields/value pairs.
		foreach (get_object_vars($object) as $k => $v)
		{
			// Only process scalars that are not internal fields.
			if (is_array($v) or is_object($v) or $k[0] == '_')
			{
				continue;
			}

			// Set the primary key to the WHERE clause instead of a field to update.
			if (in_array($k, $key))
			{
				$where[] = $this->quoteName($k) . '=' . $this->quote($v);
				continue;
			}

			// Prepare and sanitize the fields and values for the database query.
			if ($v === null)
			{
				// If the value is null and we want to update nulls then set it.
				if ($nulls)
				{
					$val = 'NULL';
				}
				else
				// If the value is null and we do not want to update nulls then ignore this field.
				{
					continue;
				}
			}
			else
			// The field is not null so we prep it for update.
			{
				$val = $this->quote($v);
			}

			// Add the field to be updated.
			$fields[] = $this->quoteName($k) . '=' . $val;
		}

		// We don't have any fields to update.
		if (empty($fields))
		{
			return true;
		}

		// Set the query and execute the update.
		$this->setQuery(sprintf($statement, implode(",", $fields), implode(' AND ', $where)));

		return $this->execute();
	}

	/**
	 * Execute the SQL statement.
	 *
	 * @return  mixed  A database cursor resource on success, boolean false on failure.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	abstract public function execute();

	/**
	 * Unlocks tables in the database.
	 *
	 * @return  DatabaseDriver  Returns this object to support chaining.
	 *
	 * @since   1.0
	 * @throws  \RuntimeException
	 */
	public abstract function unlockTables();
}
Back to Top