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Developer Documentation
- Bug fixes for general core bugs in 3.11.x will end 14 Nov 2022 (12 months plus 6 months extension).
- Bug fixes for security issues in 3.11.x will end 13 Nov 2023 (18 months plus 12 months extension).
- PHP version: minimum PHP 7.3.0 Note: minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is supported too.
/lib/dml/ -> pgsql_native_moodle_database.php (source)
Differences Between: [Versions 310 and 311] [Versions 311 and 400] [Versions 311 and 401] [Versions 311 and 402] [Versions 311 and 403] [Versions 39 and 311]
1 <?php 2 // This file is part of Moodle - http://moodle.org/ 3 // 4 // Moodle is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // Moodle is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU General Public License for more details. 13 // 14 // You should have received a copy of the GNU General Public License 15 // along with Moodle. If not, see <http://www.gnu.org/licenses/>. 16 17 /** 18 * Native pgsql class representing moodle database interface. 19 * 20 * @package core_dml 21 * @copyright 2008 Petr Skoda (http://skodak.org) 22 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 23 */ 24 25 defined('MOODLE_INTERNAL') || die(); 26 27 require_once (__DIR__.'/moodle_database.php'); 28 require_once (__DIR__.'/moodle_read_slave_trait.php'); 29 require_once (__DIR__.'/pgsql_native_moodle_recordset.php'); 30 require_once (__DIR__.'/pgsql_native_moodle_temptables.php'); 31 32 /** 33 * Native pgsql class representing moodle database interface. 34 * 35 * @package core_dml 36 * @copyright 2008 Petr Skoda (http://skodak.org) 37 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 38 */ 39 class pgsql_native_moodle_database extends moodle_database { 40 use moodle_read_slave_trait { 41 select_db_handle as read_slave_select_db_handle; 42 can_use_readonly as read_slave_can_use_readonly; 43 query_start as read_slave_query_start; 44 query_end as read_slave_query_end; 45 } 46 47 /** @var array $dbhcursor keep track of open cursors */ 48 private $dbhcursor = []; 49 50 /** @var resource $pgsql database resource */ 51 protected $pgsql = null; 52 53 protected $last_error_reporting; // To handle pgsql driver default verbosity 54 55 /** @var bool savepoint hack for MDL-35506 - workaround for automatic transaction rollback on error */ 56 protected $savepointpresent = false; 57 58 /** @var int Number of cursors used (for constructing a unique ID) */ 59 protected $cursorcount = 0; 60 61 /** @var int Default number of rows to fetch at a time when using recordsets with cursors */ 62 const DEFAULT_FETCH_BUFFER_SIZE = 100000; 63 64 /** 65 * Detects if all needed PHP stuff installed. 66 * Note: can be used before connect() 67 * @return mixed true if ok, string if something 68 */ 69 public function driver_installed() { 70 if (!extension_loaded('pgsql')) { 71 return get_string('pgsqlextensionisnotpresentinphp', 'install'); 72 } 73 return true; 74 } 75 76 /** 77 * Returns database family type - describes SQL dialect 78 * Note: can be used before connect() 79 * @return string db family name (mysql, postgres, mssql, oracle, etc.) 80 */ 81 public function get_dbfamily() { 82 return 'postgres'; 83 } 84 85 /** 86 * Returns more specific database driver type 87 * Note: can be used before connect() 88 * @return string db type mysqli, pgsql, oci, mssql, sqlsrv 89 */ 90 protected function get_dbtype() { 91 return 'pgsql'; 92 } 93 94 /** 95 * Returns general database library name 96 * Note: can be used before connect() 97 * @return string db type pdo, native 98 */ 99 protected function get_dblibrary() { 100 return 'native'; 101 } 102 103 /** 104 * Returns localised database type name 105 * Note: can be used before connect() 106 * @return string 107 */ 108 public function get_name() { 109 return get_string('nativepgsql', 'install'); 110 } 111 112 /** 113 * Returns localised database configuration help. 114 * Note: can be used before connect() 115 * @return string 116 */ 117 public function get_configuration_help() { 118 return get_string('nativepgsqlhelp', 'install'); 119 } 120 121 /** 122 * Connect to db 123 * @param string $dbhost The database host. 124 * @param string $dbuser The database username. 125 * @param string $dbpass The database username's password. 126 * @param string $dbname The name of the database being connected to. 127 * @param mixed $prefix string means moodle db prefix, false used for external databases where prefix not used 128 * @param array $dboptions driver specific options 129 * @return bool true 130 * @throws dml_connection_exception if error 131 */ 132 public function raw_connect(string $dbhost, string $dbuser, string $dbpass, string $dbname, $prefix, array $dboptions=null): bool { 133 if ($prefix == '' and !$this->external) { 134 //Enforce prefixes for everybody but mysql 135 throw new dml_exception('prefixcannotbeempty', $this->get_dbfamily()); 136 } 137 138 $driverstatus = $this->driver_installed(); 139 140 if ($driverstatus !== true) { 141 throw new dml_exception('dbdriverproblem', $driverstatus); 142 } 143 144 $this->store_settings($dbhost, $dbuser, $dbpass, $dbname, $prefix, $dboptions); 145 146 $pass = addcslashes($this->dbpass, "'\\"); 147 148 // Unix socket connections should have lower overhead 149 if (!empty($this->dboptions['dbsocket']) and ($this->dbhost === 'localhost' or $this->dbhost === '127.0.0.1')) { 150 $connection = "user='$this->dbuser' password='$pass' dbname='$this->dbname'"; 151 if (strpos($this->dboptions['dbsocket'], '/') !== false) { 152 // A directory was specified as the socket location. 153 $connection .= " host='".$this->dboptions['dbsocket']."'"; 154 } 155 if (!empty($this->dboptions['dbport'])) { 156 // A port as specified, add it to the connection as it's used as part of the socket path. 157 $connection .= " port ='".$this->dboptions['dbport']."'"; 158 } 159 } else { 160 $this->dboptions['dbsocket'] = ''; 161 if (empty($this->dbname)) { 162 // probably old style socket connection - do not add port 163 $port = ""; 164 } else if (empty($this->dboptions['dbport'])) { 165 $port = "port ='5432'"; 166 } else { 167 $port = "port ='".$this->dboptions['dbport']."'"; 168 } 169 $connection = "host='$this->dbhost' $port user='$this->dbuser' password='$pass' dbname='$this->dbname'"; 170 } 171 172 if (!empty($this->dboptions['connecttimeout'])) { 173 $connection .= " connect_timeout=".$this->dboptions['connecttimeout']; 174 } 175 176 if (empty($this->dboptions['dbhandlesoptions'])) { 177 // ALTER USER and ALTER DATABASE are overridden by these settings. 178 $options = array('--client_encoding=utf8', '--standard_conforming_strings=on'); 179 // Select schema if specified, otherwise the first one wins. 180 if (!empty($this->dboptions['dbschema'])) { 181 $options[] = "-c search_path=" . addcslashes($this->dboptions['dbschema'], "'\\"); 182 } 183 184 $connection .= " options='" . implode(' ', $options) . "'"; 185 } 186 187 ob_start(); 188 // It seems that pg_connect() handles some errors differently. 189 // For example, name resolution error will raise an exception, and non-existing 190 // database or wrong credentials will just return false. 191 // We need to cater for both. 192 try { 193 if (empty($this->dboptions['dbpersist'])) { 194 $this->pgsql = pg_connect($connection, PGSQL_CONNECT_FORCE_NEW); 195 } else { 196 $this->pgsql = pg_pconnect($connection, PGSQL_CONNECT_FORCE_NEW); 197 } 198 $dberr = ob_get_contents(); 199 } catch (\Exception $e) { 200 $dberr = $e->getMessage(); 201 } 202 ob_end_clean(); 203 204 $status = $this->pgsql ? pg_connection_status($this->pgsql) : false; 205 206 if ($status === false or $status === PGSQL_CONNECTION_BAD) { 207 $this->pgsql = null; 208 throw new dml_connection_exception($dberr); 209 } 210 211 if (!empty($this->dboptions['dbpersist'])) { 212 // There are rare situations (such as PHP out of memory errors) when open cursors may 213 // not be closed at the end of a connection. When using persistent connections, the 214 // cursors remain open and 'get in the way' of future connections. To avoid this 215 // problem, close all cursors here. 216 $result = pg_query($this->pgsql, 'CLOSE ALL'); 217 if ($result) { 218 pg_free_result($result); 219 } 220 } 221 222 if (!empty($this->dboptions['dbhandlesoptions'])) { 223 /* We don't trust people who just set the dbhandlesoptions, this code checks up on them. 224 * These functions do not talk to the server, they use the client library knowledge to determine state. 225 */ 226 if (!empty($this->dboptions['dbschema'])) { 227 throw new dml_connection_exception('You cannot specify a schema with dbhandlesoptions, use the database to set it.'); 228 } 229 if (pg_client_encoding($this->pgsql) != 'UTF8') { 230 throw new dml_connection_exception('client_encoding = UTF8 not set, it is: ' . pg_client_encoding($this->pgsql)); 231 } 232 if (pg_escape_string($this->pgsql, '\\') != '\\') { 233 throw new dml_connection_exception('standard_conforming_strings = on, must be set at the database.'); 234 } 235 } 236 237 // Connection stabilised and configured, going to instantiate the temptables controller 238 $this->temptables = new pgsql_native_moodle_temptables($this); 239 240 return true; 241 } 242 243 /** 244 * Close database connection and release all resources 245 * and memory (especially circular memory references). 246 * Do NOT use connect() again, create a new instance if needed. 247 */ 248 public function dispose() { 249 parent::dispose(); // Call parent dispose to write/close session and other common stuff before closing connection 250 if ($this->pgsql) { 251 pg_close($this->pgsql); 252 $this->pgsql = null; 253 } 254 } 255 256 /** 257 * Gets db handle currently used with queries 258 * @return resource 259 */ 260 protected function get_db_handle() { 261 return $this->pgsql; 262 } 263 264 /** 265 * Sets db handle to be used with subsequent queries 266 * @param resource $dbh 267 * @return void 268 */ 269 protected function set_db_handle($dbh): void { 270 $this->pgsql = $dbh; 271 } 272 273 /** 274 * Select appropriate db handle - readwrite or readonly 275 * @param int $type type of query 276 * @param string $sql 277 * @return void 278 */ 279 protected function select_db_handle(int $type, string $sql): void { 280 $this->read_slave_select_db_handle($type, $sql); 281 282 if (preg_match('/^DECLARE (crs\w*) NO SCROLL CURSOR/', $sql, $match)) { 283 $cursor = $match[1]; 284 $this->dbhcursor[$cursor] = $this->pgsql; 285 } 286 if (preg_match('/^(?:FETCH \d+ FROM|CLOSE) (crs\w*)\b/', $sql, $match)) { 287 $cursor = $match[1]; 288 $this->pgsql = $this->dbhcursor[$cursor]; 289 } 290 } 291 292 /** 293 * Check if The query qualifies for readonly connection execution 294 * Logging queries are exempt, those are write operations that circumvent 295 * standard query_start/query_end paths. 296 * @param int $type type of query 297 * @param string $sql 298 * @return bool 299 */ 300 protected function can_use_readonly(int $type, string $sql): bool { 301 // ... pg_*lock queries always go to master. 302 if (preg_match('/\bpg_\w*lock/', $sql)) { 303 return false; 304 } 305 306 // ... a nuisance - temptables use this. 307 if (preg_match('/\bpg_catalog/', $sql) && $this->temptables->get_temptables()) { 308 return false; 309 } 310 311 return $this->read_slave_can_use_readonly($type, $sql); 312 313 } 314 315 /** 316 * Called before each db query. 317 * @param string $sql 318 * @param array|null $params An array of parameters. 319 * @param int $type type of query 320 * @param mixed $extrainfo driver specific extra information 321 * @return void 322 */ 323 protected function query_start($sql, ?array $params, $type, $extrainfo=null) { 324 $this->read_slave_query_start($sql, $params, $type, $extrainfo); 325 // pgsql driver tends to send debug to output, we do not need that. 326 $this->last_error_reporting = error_reporting(0); 327 } 328 329 /** 330 * Called immediately after each db query. 331 * @param mixed db specific result 332 * @return void 333 */ 334 protected function query_end($result) { 335 // reset original debug level 336 error_reporting($this->last_error_reporting); 337 try { 338 $this->read_slave_query_end($result); 339 if ($this->savepointpresent and $this->last_type != SQL_QUERY_AUX and $this->last_type != SQL_QUERY_SELECT) { 340 $res = @pg_query($this->pgsql, "RELEASE SAVEPOINT moodle_pg_savepoint; SAVEPOINT moodle_pg_savepoint"); 341 if ($res) { 342 pg_free_result($res); 343 } 344 } 345 } catch (Exception $e) { 346 if ($this->savepointpresent) { 347 $res = @pg_query($this->pgsql, "ROLLBACK TO SAVEPOINT moodle_pg_savepoint; SAVEPOINT moodle_pg_savepoint"); 348 if ($res) { 349 pg_free_result($res); 350 } 351 } 352 throw $e; 353 } 354 } 355 356 /** 357 * Returns database server info array 358 * @return array Array containing 'description' and 'version' info 359 */ 360 public function get_server_info() { 361 static $info; 362 if (!$info) { 363 $this->query_start("--pg_version()", null, SQL_QUERY_AUX); 364 $info = pg_version($this->pgsql); 365 $this->query_end(true); 366 } 367 return array('description'=>$info['server'], 'version'=>$info['server']); 368 } 369 370 /** 371 * Returns supported query parameter types 372 * @return int bitmask of accepted SQL_PARAMS_* 373 */ 374 protected function allowed_param_types() { 375 return SQL_PARAMS_DOLLAR; 376 } 377 378 /** 379 * Returns last error reported by database engine. 380 * @return string error message 381 */ 382 public function get_last_error() { 383 return pg_last_error($this->pgsql); 384 } 385 386 /** 387 * Return tables in database WITHOUT current prefix. 388 * @param bool $usecache if true, returns list of cached tables. 389 * @return array of table names in lowercase and without prefix 390 */ 391 public function get_tables($usecache=true) { 392 if ($usecache and $this->tables !== null) { 393 return $this->tables; 394 } 395 $this->tables = array(); 396 $prefix = str_replace('_', '|_', $this->prefix); 397 $sql = "SELECT c.relname 398 FROM pg_catalog.pg_class c 399 JOIN pg_catalog.pg_namespace as ns ON ns.oid = c.relnamespace 400 WHERE c.relname LIKE '$prefix%' ESCAPE '|' 401 AND c.relkind = 'r' 402 AND (ns.nspname = current_schema() OR ns.oid = pg_my_temp_schema())"; 403 $this->query_start($sql, null, SQL_QUERY_AUX); 404 $result = pg_query($this->pgsql, $sql); 405 $this->query_end($result); 406 407 if ($result) { 408 while ($row = pg_fetch_row($result)) { 409 $tablename = reset($row); 410 if ($this->prefix !== false && $this->prefix !== '') { 411 if (strpos($tablename, $this->prefix) !== 0) { 412 continue; 413 } 414 $tablename = substr($tablename, strlen($this->prefix)); 415 } 416 $this->tables[$tablename] = $tablename; 417 } 418 pg_free_result($result); 419 } 420 return $this->tables; 421 } 422 423 /** 424 * Constructs 'IN()' or '=' sql fragment 425 * 426 * Method overriding {@see moodle_database::get_in_or_equal} to be able to use 427 * more than 65535 elements in $items array. 428 * 429 * @param mixed $items A single value or array of values for the expression. 430 * @param int $type Parameter bounding type : SQL_PARAMS_QM or SQL_PARAMS_NAMED. 431 * @param string $prefix Named parameter placeholder prefix (a unique counter value is appended to each parameter name). 432 * @param bool $equal True means we want to equate to the constructed expression, false means we don't want to equate to it. 433 * @param mixed $onemptyitems This defines the behavior when the array of items provided is empty. Defaults to false, 434 * meaning throw exceptions. Other values will become part of the returned SQL fragment. 435 * @throws coding_exception | dml_exception 436 * @return array A list containing the constructed sql fragment and an array of parameters. 437 */ 438 public function get_in_or_equal($items, $type=SQL_PARAMS_QM, $prefix='param', $equal=true, $onemptyitems=false): array { 439 // We only interfere if number of items in expression exceeds 16 bit value. 440 if (!is_array($items) || count($items) < 65535) { 441 return parent::get_in_or_equal($items, $type, $prefix, $equal, $onemptyitems); 442 } 443 444 // Determine the type from the first value. We don't need to be very smart here, 445 // it is developer's responsibility to make sure that variable type is matching 446 // field type, if not the case, DB engine will hint. Also mixing types won't work 447 // here anyway, so we ignore NULL or boolean (unlikely you need 56k values of 448 // these types only). 449 $cast = is_string(current($items)) ? '::text' : '::bigint'; 450 451 if ($type == SQL_PARAMS_QM) { 452 if ($equal) { 453 $sql = 'IN (VALUES ('.implode('),(', array_fill(0, count($items), '?'.$cast)).'))'; 454 } else { 455 $sql = 'NOT IN (VALUES ('.implode('),(', array_fill(0, count($items), '?'.$cast)).'))'; 456 } 457 $params = array_values($items); 458 } else if ($type == SQL_PARAMS_NAMED) { 459 if (empty($prefix)) { 460 $prefix = 'param'; 461 } 462 $params = []; 463 $sql = []; 464 foreach ($items as $item) { 465 $param = $prefix.$this->inorequaluniqueindex++; 466 $params[$param] = $item; 467 $sql[] = ':'.$param.$cast; 468 } 469 if ($equal) { 470 $sql = 'IN (VALUES ('.implode('),(', $sql).'))'; 471 } else { 472 $sql = 'NOT IN (VALUES ('.implode('),(', $sql).'))'; 473 } 474 } else { 475 throw new dml_exception('typenotimplement'); 476 } 477 return [$sql, $params]; 478 } 479 480 /** 481 * Return table indexes - everything lowercased. 482 * @param string $table The table we want to get indexes from. 483 * @return array of arrays 484 */ 485 public function get_indexes($table) { 486 $indexes = array(); 487 $tablename = $this->prefix.$table; 488 489 $sql = "SELECT i.* 490 FROM pg_catalog.pg_indexes i 491 JOIN pg_catalog.pg_namespace as ns ON ns.nspname = i.schemaname 492 WHERE i.tablename = '$tablename' 493 AND (i.schemaname = current_schema() OR ns.oid = pg_my_temp_schema())"; 494 495 $this->query_start($sql, null, SQL_QUERY_AUX); 496 $result = pg_query($this->pgsql, $sql); 497 $this->query_end($result); 498 499 if ($result) { 500 while ($row = pg_fetch_assoc($result)) { 501 // The index definition could be generated schema-qualifying the target table name 502 // for safety, depending on the pgsql version (CVE-2018-1058). 503 if (!preg_match('/CREATE (|UNIQUE )INDEX ([^\s]+) ON (|'.$row['schemaname'].'\.)'.$tablename.' USING ([^\s]+) \(([^\)]+)\)/i', $row['indexdef'], $matches)) { 504 continue; 505 } 506 if ($matches[5] === 'id') { 507 continue; 508 } 509 $columns = explode(',', $matches[5]); 510 foreach ($columns as $k=>$column) { 511 $column = trim($column); 512 if ($pos = strpos($column, ' ')) { 513 // index type is separated by space 514 $column = substr($column, 0, $pos); 515 } 516 $columns[$k] = $this->trim_quotes($column); 517 } 518 $indexes[$row['indexname']] = array('unique'=>!empty($matches[1]), 519 'columns'=>$columns); 520 } 521 pg_free_result($result); 522 } 523 return $indexes; 524 } 525 526 /** 527 * Returns detailed information about columns in table. 528 * 529 * @param string $table name 530 * @return database_column_info[] array of database_column_info objects indexed with column names 531 */ 532 protected function fetch_columns(string $table): array { 533 $structure = array(); 534 535 $tablename = $this->prefix.$table; 536 537 $sql = "SELECT a.attnum, a.attname AS field, t.typname AS type, a.attlen, a.atttypmod, a.attnotnull, a.atthasdef, 538 CASE WHEN a.atthasdef THEN pg_catalog.pg_get_expr(d.adbin, d.adrelid) END AS adsrc 539 FROM pg_catalog.pg_class c 540 JOIN pg_catalog.pg_namespace as ns ON ns.oid = c.relnamespace 541 JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid 542 JOIN pg_catalog.pg_type t ON t.oid = a.atttypid 543 LEFT JOIN pg_catalog.pg_attrdef d ON (d.adrelid = c.oid AND d.adnum = a.attnum) 544 WHERE relkind = 'r' AND c.relname = '$tablename' AND c.reltype > 0 AND a.attnum > 0 545 AND (ns.nspname = current_schema() OR ns.oid = pg_my_temp_schema()) 546 ORDER BY a.attnum"; 547 548 $this->query_start($sql, null, SQL_QUERY_AUX); 549 $result = pg_query($this->pgsql, $sql); 550 $this->query_end($result); 551 552 if (!$result) { 553 return array(); 554 } 555 while ($rawcolumn = pg_fetch_object($result)) { 556 557 $info = new stdClass(); 558 $info->name = $rawcolumn->field; 559 $matches = null; 560 561 if ($rawcolumn->type === 'varchar') { 562 $info->type = 'varchar'; 563 $info->meta_type = 'C'; 564 $info->max_length = $rawcolumn->atttypmod - 4; 565 $info->scale = null; 566 $info->not_null = ($rawcolumn->attnotnull === 't'); 567 $info->has_default = ($rawcolumn->atthasdef === 't'); 568 if ($info->has_default) { 569 $parts = explode('::', $rawcolumn->adsrc); 570 if (count($parts) > 1) { 571 $info->default_value = reset($parts); 572 $info->default_value = trim($info->default_value, "'"); 573 } else { 574 $info->default_value = $rawcolumn->adsrc; 575 } 576 } else { 577 $info->default_value = null; 578 } 579 $info->primary_key = false; 580 $info->binary = false; 581 $info->unsigned = null; 582 $info->auto_increment= false; 583 $info->unique = null; 584 585 } else if (preg_match('/int(\d)/i', $rawcolumn->type, $matches)) { 586 $info->type = 'int'; 587 if (strpos($rawcolumn->adsrc, 'nextval') === 0) { 588 $info->primary_key = true; 589 $info->meta_type = 'R'; 590 $info->unique = true; 591 $info->auto_increment= true; 592 $info->has_default = false; 593 } else { 594 $info->primary_key = false; 595 $info->meta_type = 'I'; 596 $info->unique = null; 597 $info->auto_increment= false; 598 $info->has_default = ($rawcolumn->atthasdef === 't'); 599 } 600 // Return number of decimals, not bytes here. 601 if ($matches[1] >= 8) { 602 $info->max_length = 18; 603 } else if ($matches[1] >= 4) { 604 $info->max_length = 9; 605 } else if ($matches[1] >= 2) { 606 $info->max_length = 4; 607 } else if ($matches[1] >= 1) { 608 $info->max_length = 2; 609 } else { 610 $info->max_length = 0; 611 } 612 $info->scale = null; 613 $info->not_null = ($rawcolumn->attnotnull === 't'); 614 if ($info->has_default) { 615 // PG 9.5+ uses ::<TYPE> syntax for some defaults. 616 $parts = explode('::', $rawcolumn->adsrc); 617 if (count($parts) > 1) { 618 $info->default_value = reset($parts); 619 } else { 620 $info->default_value = $rawcolumn->adsrc; 621 } 622 $info->default_value = trim($info->default_value, "()'"); 623 } else { 624 $info->default_value = null; 625 } 626 $info->binary = false; 627 $info->unsigned = false; 628 629 } else if ($rawcolumn->type === 'numeric') { 630 $info->type = $rawcolumn->type; 631 $info->meta_type = 'N'; 632 $info->primary_key = false; 633 $info->binary = false; 634 $info->unsigned = null; 635 $info->auto_increment= false; 636 $info->unique = null; 637 $info->not_null = ($rawcolumn->attnotnull === 't'); 638 $info->has_default = ($rawcolumn->atthasdef === 't'); 639 if ($info->has_default) { 640 // PG 9.5+ uses ::<TYPE> syntax for some defaults. 641 $parts = explode('::', $rawcolumn->adsrc); 642 if (count($parts) > 1) { 643 $info->default_value = reset($parts); 644 } else { 645 $info->default_value = $rawcolumn->adsrc; 646 } 647 $info->default_value = trim($info->default_value, "()'"); 648 } else { 649 $info->default_value = null; 650 } 651 $info->max_length = $rawcolumn->atttypmod >> 16; 652 $info->scale = ($rawcolumn->atttypmod & 0xFFFF) - 4; 653 654 } else if (preg_match('/float(\d)/i', $rawcolumn->type, $matches)) { 655 $info->type = 'float'; 656 $info->meta_type = 'N'; 657 $info->primary_key = false; 658 $info->binary = false; 659 $info->unsigned = null; 660 $info->auto_increment= false; 661 $info->unique = null; 662 $info->not_null = ($rawcolumn->attnotnull === 't'); 663 $info->has_default = ($rawcolumn->atthasdef === 't'); 664 if ($info->has_default) { 665 // PG 9.5+ uses ::<TYPE> syntax for some defaults. 666 $parts = explode('::', $rawcolumn->adsrc); 667 if (count($parts) > 1) { 668 $info->default_value = reset($parts); 669 } else { 670 $info->default_value = $rawcolumn->adsrc; 671 } 672 $info->default_value = trim($info->default_value, "()'"); 673 } else { 674 $info->default_value = null; 675 } 676 // just guess expected number of deciaml places :-( 677 if ($matches[1] == 8) { 678 // total 15 digits 679 $info->max_length = 8; 680 $info->scale = 7; 681 } else { 682 // total 6 digits 683 $info->max_length = 4; 684 $info->scale = 2; 685 } 686 687 } else if ($rawcolumn->type === 'text') { 688 $info->type = $rawcolumn->type; 689 $info->meta_type = 'X'; 690 $info->max_length = -1; 691 $info->scale = null; 692 $info->not_null = ($rawcolumn->attnotnull === 't'); 693 $info->has_default = ($rawcolumn->atthasdef === 't'); 694 if ($info->has_default) { 695 $parts = explode('::', $rawcolumn->adsrc); 696 if (count($parts) > 1) { 697 $info->default_value = reset($parts); 698 $info->default_value = trim($info->default_value, "'"); 699 } else { 700 $info->default_value = $rawcolumn->adsrc; 701 } 702 } else { 703 $info->default_value = null; 704 } 705 $info->primary_key = false; 706 $info->binary = false; 707 $info->unsigned = null; 708 $info->auto_increment= false; 709 $info->unique = null; 710 711 } else if ($rawcolumn->type === 'bytea') { 712 $info->type = $rawcolumn->type; 713 $info->meta_type = 'B'; 714 $info->max_length = -1; 715 $info->scale = null; 716 $info->not_null = ($rawcolumn->attnotnull === 't'); 717 $info->has_default = false; 718 $info->default_value = null; 719 $info->primary_key = false; 720 $info->binary = true; 721 $info->unsigned = null; 722 $info->auto_increment= false; 723 $info->unique = null; 724 725 } 726 727 $structure[$info->name] = new database_column_info($info); 728 } 729 730 pg_free_result($result); 731 732 return $structure; 733 } 734 735 /** 736 * Normalise values based in RDBMS dependencies (booleans, LOBs...) 737 * 738 * @param database_column_info $column column metadata corresponding with the value we are going to normalise 739 * @param mixed $value value we are going to normalise 740 * @return mixed the normalised value 741 */ 742 protected function normalise_value($column, $value) { 743 $this->detect_objects($value); 744 745 if (is_bool($value)) { // Always, convert boolean to int 746 $value = (int)$value; 747 748 } else if ($column->meta_type === 'B') { 749 if (!is_null($value)) { 750 // standard_conforming_strings must be enabled, otherwise pg_escape_bytea() will double escape 751 // \ and produce data errors. This is set on the connection. 752 $value = pg_escape_bytea($this->pgsql, $value); 753 } 754 755 } else if ($value === '') { 756 if ($column->meta_type === 'I' or $column->meta_type === 'F' or $column->meta_type === 'N') { 757 $value = 0; // prevent '' problems in numeric fields 758 } 759 } 760 return $value; 761 } 762 763 /** 764 * Is db in unicode mode? 765 * @return bool 766 */ 767 public function setup_is_unicodedb() { 768 // Get PostgreSQL server_encoding value 769 $sql = "SHOW server_encoding"; 770 $this->query_start($sql, null, SQL_QUERY_AUX); 771 $result = pg_query($this->pgsql, $sql); 772 $this->query_end($result); 773 774 if (!$result) { 775 return false; 776 } 777 $rawcolumn = pg_fetch_object($result); 778 $encoding = $rawcolumn->server_encoding; 779 pg_free_result($result); 780 781 return (strtoupper($encoding) == 'UNICODE' || strtoupper($encoding) == 'UTF8'); 782 } 783 784 /** 785 * Do NOT use in code, to be used by database_manager only! 786 * @param string|array $sql query 787 * @param array|null $tablenames an array of xmldb table names affected by this request. 788 * @return bool true 789 * @throws ddl_change_structure_exception A DDL specific exception is thrown for any errors. 790 */ 791 public function change_database_structure($sql, $tablenames = null) { 792 $this->get_manager(); // Includes DDL exceptions classes ;-) 793 if (is_array($sql)) { 794 $sql = implode("\n;\n", $sql); 795 } 796 if (!$this->is_transaction_started()) { 797 // It is better to do all or nothing, this helps with recovery... 798 $sql = "BEGIN ISOLATION LEVEL SERIALIZABLE;\n$sql\n; COMMIT"; 799 } 800 801 try { 802 $this->query_start($sql, null, SQL_QUERY_STRUCTURE); 803 $result = pg_query($this->pgsql, $sql); 804 $this->query_end($result); 805 pg_free_result($result); 806 } catch (ddl_change_structure_exception $e) { 807 if (!$this->is_transaction_started()) { 808 $result = @pg_query($this->pgsql, "ROLLBACK"); 809 @pg_free_result($result); 810 } 811 $this->reset_caches($tablenames); 812 throw $e; 813 } 814 815 $this->reset_caches($tablenames); 816 return true; 817 } 818 819 /** 820 * Execute general sql query. Should be used only when no other method suitable. 821 * Do NOT use this to make changes in db structure, use database_manager methods instead! 822 * @param string $sql query 823 * @param array $params query parameters 824 * @return bool true 825 * @throws dml_exception A DML specific exception is thrown for any errors. 826 */ 827 public function execute($sql, array $params=null) { 828 list($sql, $params, $type) = $this->fix_sql_params($sql, $params); 829 830 if (strpos($sql, ';') !== false) { 831 throw new coding_exception('moodle_database::execute() Multiple sql statements found or bound parameters not used properly in query!'); 832 } 833 834 $this->query_start($sql, $params, SQL_QUERY_UPDATE); 835 $result = pg_query_params($this->pgsql, $sql, $params); 836 $this->query_end($result); 837 838 pg_free_result($result); 839 return true; 840 } 841 842 /** 843 * Get a number of records as a moodle_recordset using a SQL statement. 844 * 845 * Since this method is a little less readable, use of it should be restricted to 846 * code where it's possible there might be large datasets being returned. For known 847 * small datasets use get_records_sql - it leads to simpler code. 848 * 849 * The return type is like: 850 * @see function get_recordset. 851 * 852 * @param string $sql the SQL select query to execute. 853 * @param array $params array of sql parameters 854 * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set). 855 * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set). 856 * @return moodle_recordset instance 857 * @throws dml_exception A DML specific exception is thrown for any errors. 858 */ 859 public function get_recordset_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) { 860 861 list($limitfrom, $limitnum) = $this->normalise_limit_from_num($limitfrom, $limitnum); 862 863 if ($limitnum) { 864 $sql .= " LIMIT $limitnum"; 865 } 866 if ($limitfrom) { 867 $sql .= " OFFSET $limitfrom"; 868 } 869 870 list($sql, $params, $type) = $this->fix_sql_params($sql, $params); 871 872 // For any query that doesn't explicitly specify a limit, we must use cursors to stop it 873 // loading the entire thing (unless the config setting is turned off). 874 $usecursors = !$limitnum && ($this->get_fetch_buffer_size() > 0); 875 if ($usecursors) { 876 // Work out the cursor unique identifer. This is based on a simple count used which 877 // should be OK because the identifiers only need to be unique within the current 878 // transaction. 879 $this->cursorcount++; 880 $cursorname = 'crs' . $this->cursorcount; 881 882 // Do the query to a cursor. 883 $sql = 'DECLARE ' . $cursorname . ' NO SCROLL CURSOR WITH HOLD FOR ' . $sql; 884 } else { 885 $cursorname = ''; 886 } 887 888 $this->query_start($sql, $params, SQL_QUERY_SELECT); 889 890 $result = pg_query_params($this->pgsql, $sql, $params); 891 892 $this->query_end($result); 893 if ($usecursors) { 894 pg_free_result($result); 895 $result = null; 896 } 897 898 return new pgsql_native_moodle_recordset($result, $this, $cursorname); 899 } 900 901 /** 902 * Gets size of fetch buffer used for recordset queries. 903 * 904 * If this returns 0 then cursors will not be used, meaning recordset queries will occupy enough 905 * memory as needed for the Postgres library to hold the entire query results in memory. 906 * 907 * @return int Fetch buffer size or 0 indicating not to use cursors 908 */ 909 protected function get_fetch_buffer_size() { 910 if (array_key_exists('fetchbuffersize', $this->dboptions)) { 911 return (int)$this->dboptions['fetchbuffersize']; 912 } else { 913 return self::DEFAULT_FETCH_BUFFER_SIZE; 914 } 915 } 916 917 /** 918 * Retrieves data from cursor. For use by recordset only; do not call directly. 919 * 920 * Return value contains the next batch of Postgres data, and a boolean indicating if this is 921 * definitely the last batch (if false, there may be more) 922 * 923 * @param string $cursorname Name of cursor to read from 924 * @return array Array with 2 elements (next data batch and boolean indicating last batch) 925 */ 926 public function fetch_from_cursor($cursorname) { 927 $count = $this->get_fetch_buffer_size(); 928 929 $sql = 'FETCH ' . $count . ' FROM ' . $cursorname; 930 931 $this->query_start($sql, [], SQL_QUERY_AUX); 932 $result = pg_query($this->pgsql, $sql); 933 $last = pg_num_rows($result) !== $count; 934 935 $this->query_end($result); 936 937 return [$result, $last]; 938 } 939 940 /** 941 * Closes a cursor. For use by recordset only; do not call directly. 942 * 943 * @param string $cursorname Name of cursor to close 944 * @return bool True if we actually closed one, false if the transaction was cancelled 945 */ 946 public function close_cursor($cursorname) { 947 // If the transaction got cancelled, then ignore this request. 948 $sql = 'CLOSE ' . $cursorname; 949 $this->query_start($sql, [], SQL_QUERY_AUX); 950 $result = pg_query($this->pgsql, $sql); 951 $this->query_end($result); 952 if ($result) { 953 pg_free_result($result); 954 } 955 return true; 956 } 957 958 /** 959 * Get a number of records as an array of objects using a SQL statement. 960 * 961 * Return value is like: 962 * @see function get_records. 963 * 964 * @param string $sql the SQL select query to execute. The first column of this SELECT statement 965 * must be a unique value (usually the 'id' field), as it will be used as the key of the 966 * returned array. 967 * @param array $params array of sql parameters 968 * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set). 969 * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set). 970 * @return array of objects, or empty array if no records were found 971 * @throws dml_exception A DML specific exception is thrown for any errors. 972 */ 973 public function get_records_sql($sql, array $params = null, $limitfrom = 0, $limitnum = 0) { 974 list($limitfrom, $limitnum) = $this->normalise_limit_from_num($limitfrom, $limitnum); 975 976 if ($limitnum) { 977 $sql .= " LIMIT $limitnum"; 978 } 979 if ($limitfrom) { 980 $sql .= " OFFSET $limitfrom"; 981 } 982 983 list($sql, $params, $type) = $this->fix_sql_params($sql, $params); 984 $this->query_start($sql, $params, SQL_QUERY_SELECT); 985 $result = pg_query_params($this->pgsql, $sql, $params); 986 $this->query_end($result); 987 988 // find out if there are any blobs 989 $numfields = pg_num_fields($result); 990 $blobs = array(); 991 for ($i = 0; $i < $numfields; $i++) { 992 $type = pg_field_type($result, $i); 993 if ($type == 'bytea') { 994 $blobs[] = pg_field_name($result, $i); 995 } 996 } 997 998 $return = []; 999 while ($row = pg_fetch_assoc($result)) { 1000 $id = reset($row); 1001 if ($blobs) { 1002 foreach ($blobs as $blob) { 1003 $row[$blob] = ($row[$blob] !== null ? pg_unescape_bytea($row[$blob]) : null); 1004 } 1005 } 1006 if (isset($return[$id])) { 1007 $colname = key($row); 1008 debugging("Did you remember to make the first column something unique in your call to get_records? Duplicate value '$id' found in column '$colname'.", DEBUG_DEVELOPER); 1009 } 1010 $return[$id] = (object) $row; 1011 } 1012 1013 return $return; 1014 } 1015 1016 /** 1017 * Selects records and return values (first field) as an array using a SQL statement. 1018 * 1019 * @param string $sql The SQL query 1020 * @param array $params array of sql parameters 1021 * @return array of values 1022 * @throws dml_exception A DML specific exception is thrown for any errors. 1023 */ 1024 public function get_fieldset_sql($sql, array $params=null) { 1025 list($sql, $params, $type) = $this->fix_sql_params($sql, $params); 1026 1027 $this->query_start($sql, $params, SQL_QUERY_SELECT); 1028 $result = pg_query_params($this->pgsql, $sql, $params); 1029 $this->query_end($result); 1030 1031 $return = pg_fetch_all_columns($result, 0); 1032 1033 if (pg_field_type($result, 0) == 'bytea') { 1034 foreach ($return as $key => $value) { 1035 $return[$key] = ($value === null ? $value : pg_unescape_bytea($value)); 1036 } 1037 } 1038 1039 pg_free_result($result); 1040 1041 return $return; 1042 } 1043 1044 /** 1045 * Insert new record into database, as fast as possible, no safety checks, lobs not supported. 1046 * @param string $table name 1047 * @param mixed $params data record as object or array 1048 * @param bool $returnit return it of inserted record 1049 * @param bool $bulk true means repeated inserts expected 1050 * @param bool $customsequence true if 'id' included in $params, disables $returnid 1051 * @return bool|int true or new id 1052 * @throws dml_exception A DML specific exception is thrown for any errors. 1053 */ 1054 public function insert_record_raw($table, $params, $returnid=true, $bulk=false, $customsequence=false) { 1055 if (!is_array($params)) { 1056 $params = (array)$params; 1057 } 1058 1059 $returning = ""; 1060 1061 if ($customsequence) { 1062 if (!isset($params['id'])) { 1063 throw new coding_exception('moodle_database::insert_record_raw() id field must be specified if custom sequences used.'); 1064 } 1065 $returnid = false; 1066 } else { 1067 if ($returnid) { 1068 $returning = "RETURNING id"; 1069 unset($params['id']); 1070 } else { 1071 unset($params['id']); 1072 } 1073 } 1074 1075 if (empty($params)) { 1076 throw new coding_exception('moodle_database::insert_record_raw() no fields found.'); 1077 } 1078 1079 $fields = implode(',', array_keys($params)); 1080 $values = array(); 1081 $i = 1; 1082 foreach ($params as $value) { 1083 $this->detect_objects($value); 1084 $values[] = "\$".$i++; 1085 } 1086 $values = implode(',', $values); 1087 1088 $sql = "INSERT INTO {$this->prefix}$table ($fields) VALUES($values) $returning"; 1089 $this->query_start($sql, $params, SQL_QUERY_INSERT); 1090 $result = pg_query_params($this->pgsql, $sql, $params); 1091 $this->query_end($result); 1092 1093 if ($returning !== "") { 1094 $row = pg_fetch_assoc($result); 1095 $params['id'] = reset($row); 1096 } 1097 pg_free_result($result); 1098 1099 if (!$returnid) { 1100 return true; 1101 } 1102 1103 return (int)$params['id']; 1104 } 1105 1106 /** 1107 * Insert a record into a table and return the "id" field if required. 1108 * 1109 * Some conversions and safety checks are carried out. Lobs are supported. 1110 * If the return ID isn't required, then this just reports success as true/false. 1111 * $data is an object containing needed data 1112 * @param string $table The database table to be inserted into 1113 * @param object|array $dataobject A data object with values for one or more fields in the record 1114 * @param bool $returnid Should the id of the newly created record entry be returned? If this option is not requested then true/false is returned. 1115 * @return bool|int true or new id 1116 * @throws dml_exception A DML specific exception is thrown for any errors. 1117 */ 1118 public function insert_record($table, $dataobject, $returnid=true, $bulk=false) { 1119 $dataobject = (array)$dataobject; 1120 1121 $columns = $this->get_columns($table); 1122 if (empty($columns)) { 1123 throw new dml_exception('ddltablenotexist', $table); 1124 } 1125 1126 $cleaned = array(); 1127 1128 foreach ($dataobject as $field=>$value) { 1129 if ($field === 'id') { 1130 continue; 1131 } 1132 if (!isset($columns[$field])) { 1133 continue; 1134 } 1135 $column = $columns[$field]; 1136 $cleaned[$field] = $this->normalise_value($column, $value); 1137 } 1138 1139 return $this->insert_record_raw($table, $cleaned, $returnid, $bulk); 1140 1141 } 1142 1143 /** 1144 * Insert multiple records into database as fast as possible. 1145 * 1146 * Order of inserts is maintained, but the operation is not atomic, 1147 * use transactions if necessary. 1148 * 1149 * This method is intended for inserting of large number of small objects, 1150 * do not use for huge objects with text or binary fields. 1151 * 1152 * @since Moodle 2.7 1153 * 1154 * @param string $table The database table to be inserted into 1155 * @param array|Traversable $dataobjects list of objects to be inserted, must be compatible with foreach 1156 * @return void does not return new record ids 1157 * 1158 * @throws coding_exception if data objects have different structure 1159 * @throws dml_exception A DML specific exception is thrown for any errors. 1160 */ 1161 public function insert_records($table, $dataobjects) { 1162 if (!is_array($dataobjects) and !($dataobjects instanceof Traversable)) { 1163 throw new coding_exception('insert_records() passed non-traversable object'); 1164 } 1165 1166 // PostgreSQL does not seem to have problems with huge queries. 1167 $chunksize = 500; 1168 if (!empty($this->dboptions['bulkinsertsize'])) { 1169 $chunksize = (int)$this->dboptions['bulkinsertsize']; 1170 } 1171 1172 $columns = $this->get_columns($table, true); 1173 1174 $fields = null; 1175 $count = 0; 1176 $chunk = array(); 1177 foreach ($dataobjects as $dataobject) { 1178 if (!is_array($dataobject) and !is_object($dataobject)) { 1179 throw new coding_exception('insert_records() passed invalid record object'); 1180 } 1181 $dataobject = (array)$dataobject; 1182 if ($fields === null) { 1183 $fields = array_keys($dataobject); 1184 $columns = array_intersect_key($columns, $dataobject); 1185 unset($columns['id']); 1186 } else if ($fields !== array_keys($dataobject)) { 1187 throw new coding_exception('All dataobjects in insert_records() must have the same structure!'); 1188 } 1189 1190 $count++; 1191 $chunk[] = $dataobject; 1192 1193 if ($count === $chunksize) { 1194 $this->insert_chunk($table, $chunk, $columns); 1195 $chunk = array(); 1196 $count = 0; 1197 } 1198 } 1199 1200 if ($count) { 1201 $this->insert_chunk($table, $chunk, $columns); 1202 } 1203 } 1204 1205 /** 1206 * Insert records in chunks, strict param types... 1207 * 1208 * Note: can be used only from insert_records(). 1209 * 1210 * @param string $table 1211 * @param array $chunk 1212 * @param database_column_info[] $columns 1213 */ 1214 protected function insert_chunk($table, array $chunk, array $columns) { 1215 $i = 1; 1216 $params = array(); 1217 $values = array(); 1218 foreach ($chunk as $dataobject) { 1219 $vals = array(); 1220 foreach ($columns as $field => $column) { 1221 $params[] = $this->normalise_value($column, $dataobject[$field]); 1222 $vals[] = "\$".$i++; 1223 } 1224 $values[] = '('.implode(',', $vals).')'; 1225 } 1226 1227 $fieldssql = '('.implode(',', array_keys($columns)).')'; 1228 $valuessql = implode(',', $values); 1229 1230 $sql = "INSERT INTO {$this->prefix}$table $fieldssql VALUES $valuessql"; 1231 $this->query_start($sql, $params, SQL_QUERY_INSERT); 1232 $result = pg_query_params($this->pgsql, $sql, $params); 1233 $this->query_end($result); 1234 pg_free_result($result); 1235 } 1236 1237 /** 1238 * Import a record into a table, id field is required. 1239 * Safety checks are NOT carried out. Lobs are supported. 1240 * 1241 * @param string $table name of database table to be inserted into 1242 * @param object $dataobject A data object with values for one or more fields in the record 1243 * @return bool true 1244 * @throws dml_exception A DML specific exception is thrown for any errors. 1245 */ 1246 public function import_record($table, $dataobject) { 1247 $dataobject = (array)$dataobject; 1248 1249 $columns = $this->get_columns($table); 1250 $cleaned = array(); 1251 1252 foreach ($dataobject as $field=>$value) { 1253 $this->detect_objects($value); 1254 if (!isset($columns[$field])) { 1255 continue; 1256 } 1257 $column = $columns[$field]; 1258 $cleaned[$field] = $this->normalise_value($column, $value); 1259 } 1260 1261 return $this->insert_record_raw($table, $cleaned, false, true, true); 1262 } 1263 1264 /** 1265 * Update record in database, as fast as possible, no safety checks, lobs not supported. 1266 * @param string $table name 1267 * @param mixed $params data record as object or array 1268 * @param bool true means repeated updates expected 1269 * @return bool true 1270 * @throws dml_exception A DML specific exception is thrown for any errors. 1271 */ 1272 public function update_record_raw($table, $params, $bulk=false) { 1273 $params = (array)$params; 1274 1275 if (!isset($params['id'])) { 1276 throw new coding_exception('moodle_database::update_record_raw() id field must be specified.'); 1277 } 1278 $id = $params['id']; 1279 unset($params['id']); 1280 1281 if (empty($params)) { 1282 throw new coding_exception('moodle_database::update_record_raw() no fields found.'); 1283 } 1284 1285 $i = 1; 1286 1287 $sets = array(); 1288 foreach ($params as $field=>$value) { 1289 $this->detect_objects($value); 1290 $sets[] = "$field = \$".$i++; 1291 } 1292 1293 $params[] = $id; // last ? in WHERE condition 1294 1295 $sets = implode(',', $sets); 1296 $sql = "UPDATE {$this->prefix}$table SET $sets WHERE id=\$".$i; 1297 1298 $this->query_start($sql, $params, SQL_QUERY_UPDATE); 1299 $result = pg_query_params($this->pgsql, $sql, $params); 1300 $this->query_end($result); 1301 1302 pg_free_result($result); 1303 return true; 1304 } 1305 1306 /** 1307 * Update a record in a table 1308 * 1309 * $dataobject is an object containing needed data 1310 * Relies on $dataobject having a variable "id" to 1311 * specify the record to update 1312 * 1313 * @param string $table The database table to be checked against. 1314 * @param object $dataobject An object with contents equal to fieldname=>fieldvalue. Must have an entry for 'id' to map to the table specified. 1315 * @param bool true means repeated updates expected 1316 * @return bool true 1317 * @throws dml_exception A DML specific exception is thrown for any errors. 1318 */ 1319 public function update_record($table, $dataobject, $bulk=false) { 1320 $dataobject = (array)$dataobject; 1321 1322 $columns = $this->get_columns($table); 1323 $cleaned = array(); 1324 1325 foreach ($dataobject as $field=>$value) { 1326 if (!isset($columns[$field])) { 1327 continue; 1328 } 1329 $column = $columns[$field]; 1330 $cleaned[$field] = $this->normalise_value($column, $value); 1331 } 1332 1333 $this->update_record_raw($table, $cleaned, $bulk); 1334 1335 return true; 1336 } 1337 1338 /** 1339 * Set a single field in every table record which match a particular WHERE clause. 1340 * 1341 * @param string $table The database table to be checked against. 1342 * @param string $newfield the field to set. 1343 * @param string $newvalue the value to set the field to. 1344 * @param string $select A fragment of SQL to be used in a where clause in the SQL call. 1345 * @param array $params array of sql parameters 1346 * @return bool true 1347 * @throws dml_exception A DML specific exception is thrown for any errors. 1348 */ 1349 public function set_field_select($table, $newfield, $newvalue, $select, array $params=null) { 1350 1351 if ($select) { 1352 $select = "WHERE $select"; 1353 } 1354 if (is_null($params)) { 1355 $params = array(); 1356 } 1357 list($select, $params, $type) = $this->fix_sql_params($select, $params); 1358 $i = count($params)+1; 1359 1360 // Get column metadata 1361 $columns = $this->get_columns($table); 1362 $column = $columns[$newfield]; 1363 1364 $normalisedvalue = $this->normalise_value($column, $newvalue); 1365 1366 $newfield = "$newfield = \$" . $i; 1367 $params[] = $normalisedvalue; 1368 $sql = "UPDATE {$this->prefix}$table SET $newfield $select"; 1369 1370 $this->query_start($sql, $params, SQL_QUERY_UPDATE); 1371 $result = pg_query_params($this->pgsql, $sql, $params); 1372 $this->query_end($result); 1373 1374 pg_free_result($result); 1375 1376 return true; 1377 } 1378 1379 /** 1380 * Delete one or more records from a table which match a particular WHERE clause, lobs not supported. 1381 * 1382 * @param string $table The database table to be checked against. 1383 * @param string $select A fragment of SQL to be used in a where clause in the SQL call (used to define the selection criteria). 1384 * @param array $params array of sql parameters 1385 * @return bool true 1386 * @throws dml_exception A DML specific exception is thrown for any errors. 1387 */ 1388 public function delete_records_select($table, $select, array $params=null) { 1389 if ($select) { 1390 $select = "WHERE $select"; 1391 } 1392 $sql = "DELETE FROM {$this->prefix}$table $select"; 1393 1394 list($sql, $params, $type) = $this->fix_sql_params($sql, $params); 1395 1396 $this->query_start($sql, $params, SQL_QUERY_UPDATE); 1397 $result = pg_query_params($this->pgsql, $sql, $params); 1398 $this->query_end($result); 1399 1400 pg_free_result($result); 1401 1402 return true; 1403 } 1404 1405 /** 1406 * Returns 'LIKE' part of a query. 1407 * 1408 * @param string $fieldname usually name of the table column 1409 * @param string $param usually bound query parameter (?, :named) 1410 * @param bool $casesensitive use case sensitive search 1411 * @param bool $accensensitive use accent sensitive search (not all databases support accent insensitive) 1412 * @param bool $notlike true means "NOT LIKE" 1413 * @param string $escapechar escape char for '%' and '_' 1414 * @return string SQL code fragment 1415 */ 1416 public function sql_like($fieldname, $param, $casesensitive = true, $accentsensitive = true, $notlike = false, $escapechar = '\\') { 1417 if (strpos($param, '%') !== false) { 1418 debugging('Potential SQL injection detected, sql_like() expects bound parameters (? or :named)'); 1419 } 1420 1421 // postgresql does not support accent insensitive text comparisons, sorry 1422 if ($casesensitive) { 1423 $LIKE = $notlike ? 'NOT LIKE' : 'LIKE'; 1424 } else { 1425 $LIKE = $notlike ? 'NOT ILIKE' : 'ILIKE'; 1426 } 1427 return "$fieldname $LIKE $param ESCAPE '$escapechar'"; 1428 } 1429 1430 public function sql_bitxor($int1, $int2) { 1431 return '((' . $int1 . ') # (' . $int2 . '))'; 1432 } 1433 1434 public function sql_cast_char2int($fieldname, $text=false) { 1435 return ' CAST(' . $fieldname . ' AS INT) '; 1436 } 1437 1438 public function sql_cast_char2real($fieldname, $text=false) { 1439 return " $fieldname::real "; 1440 } 1441 1442 public function sql_concat() { 1443 $arr = func_get_args(); 1444 $s = implode(' || ', $arr); 1445 if ($s === '') { 1446 return " '' "; 1447 } 1448 // Add always empty string element so integer-exclusive concats 1449 // will work without needing to cast each element explicitly 1450 return " '' || $s "; 1451 } 1452 1453 public function sql_concat_join($separator="' '", $elements=array()) { 1454 for ($n=count($elements)-1; $n > 0 ; $n--) { 1455 array_splice($elements, $n, 0, $separator); 1456 } 1457 $s = implode(' || ', $elements); 1458 if ($s === '') { 1459 return " '' "; 1460 } 1461 return " $s "; 1462 } 1463 1464 /** 1465 * Return SQL for performing group concatenation on given field/expression 1466 * 1467 * @param string $field 1468 * @param string $separator 1469 * @param string $sort 1470 * @return string 1471 */ 1472 public function sql_group_concat(string $field, string $separator = ', ', string $sort = ''): string { 1473 $fieldsort = $sort ? "ORDER BY {$sort}" : ''; 1474 return "STRING_AGG(CAST({$field} AS VARCHAR), '{$separator}' {$fieldsort})"; 1475 } 1476 1477 public function sql_regex_supported() { 1478 return true; 1479 } 1480 1481 public function sql_regex($positivematch = true, $casesensitive = false) { 1482 if ($casesensitive) { 1483 return $positivematch ? '~' : '!~'; 1484 } else { 1485 return $positivematch ? '~*' : '!~*'; 1486 } 1487 } 1488 1489 /** 1490 * Does this driver support tool_replace? 1491 * 1492 * @since Moodle 2.6.1 1493 * @return bool 1494 */ 1495 public function replace_all_text_supported() { 1496 return true; 1497 } 1498 1499 public function session_lock_supported() { 1500 return true; 1501 } 1502 1503 /** 1504 * Obtain session lock 1505 * @param int $rowid id of the row with session record 1506 * @param int $timeout max allowed time to wait for the lock in seconds 1507 * @return bool success 1508 */ 1509 public function get_session_lock($rowid, $timeout) { 1510 // NOTE: there is a potential locking problem for database running 1511 // multiple instances of moodle, we could try to use pg_advisory_lock(int, int), 1512 // luckily there is not a big chance that they would collide 1513 if (!$this->session_lock_supported()) { 1514 return; 1515 } 1516 1517 parent::get_session_lock($rowid, $timeout); 1518 1519 $timeoutmilli = $timeout * 1000; 1520 1521 $sql = "SET statement_timeout TO $timeoutmilli"; 1522 $this->query_start($sql, null, SQL_QUERY_AUX); 1523 $result = pg_query($this->pgsql, $sql); 1524 $this->query_end($result); 1525 1526 if ($result) { 1527 pg_free_result($result); 1528 } 1529 1530 $sql = "SELECT pg_advisory_lock($rowid)"; 1531 $this->query_start($sql, null, SQL_QUERY_AUX); 1532 $start = time(); 1533 $result = pg_query($this->pgsql, $sql); 1534 $end = time(); 1535 try { 1536 $this->query_end($result); 1537 } catch (dml_exception $ex) { 1538 if ($end - $start >= $timeout) { 1539 throw new dml_sessionwait_exception(); 1540 } else { 1541 throw $ex; 1542 } 1543 } 1544 1545 if ($result) { 1546 pg_free_result($result); 1547 } 1548 1549 $sql = "SET statement_timeout TO DEFAULT"; 1550 $this->query_start($sql, null, SQL_QUERY_AUX); 1551 $result = pg_query($this->pgsql, $sql); 1552 $this->query_end($result); 1553 1554 if ($result) { 1555 pg_free_result($result); 1556 } 1557 } 1558 1559 public function release_session_lock($rowid) { 1560 if (!$this->session_lock_supported()) { 1561 return; 1562 } 1563 if (!$this->used_for_db_sessions) { 1564 return; 1565 } 1566 1567 parent::release_session_lock($rowid); 1568 1569 $sql = "SELECT pg_advisory_unlock($rowid)"; 1570 $this->query_start($sql, null, SQL_QUERY_AUX); 1571 $result = pg_query($this->pgsql, $sql); 1572 $this->query_end($result); 1573 1574 if ($result) { 1575 pg_free_result($result); 1576 } 1577 } 1578 1579 /** 1580 * Driver specific start of real database transaction, 1581 * this can not be used directly in code. 1582 * @return void 1583 */ 1584 protected function begin_transaction() { 1585 $this->savepointpresent = true; 1586 $sql = "BEGIN ISOLATION LEVEL READ COMMITTED; SAVEPOINT moodle_pg_savepoint"; 1587 $this->query_start($sql, null, SQL_QUERY_AUX); 1588 $result = pg_query($this->pgsql, $sql); 1589 $this->query_end($result); 1590 1591 pg_free_result($result); 1592 } 1593 1594 /** 1595 * Driver specific commit of real database transaction, 1596 * this can not be used directly in code. 1597 * @return void 1598 */ 1599 protected function commit_transaction() { 1600 $this->savepointpresent = false; 1601 $sql = "RELEASE SAVEPOINT moodle_pg_savepoint; COMMIT"; 1602 $this->query_start($sql, null, SQL_QUERY_AUX); 1603 $result = pg_query($this->pgsql, $sql); 1604 $this->query_end($result); 1605 1606 pg_free_result($result); 1607 } 1608 1609 /** 1610 * Driver specific abort of real database transaction, 1611 * this can not be used directly in code. 1612 * @return void 1613 */ 1614 protected function rollback_transaction() { 1615 $this->savepointpresent = false; 1616 $sql = "RELEASE SAVEPOINT moodle_pg_savepoint; ROLLBACK"; 1617 $this->query_start($sql, null, SQL_QUERY_AUX); 1618 $result = pg_query($this->pgsql, $sql); 1619 $this->query_end($result); 1620 1621 pg_free_result($result); 1622 } 1623 1624 /** 1625 * Helper function trimming (whitespace + quotes) any string 1626 * needed because PG uses to enclose with double quotes some 1627 * fields in indexes definition and others 1628 * 1629 * @param string $str string to apply whitespace + quotes trim 1630 * @return string trimmed string 1631 */ 1632 private function trim_quotes($str) { 1633 return trim(trim($str), "'\""); 1634 } 1635 1636 /** 1637 * Postgresql supports full-text search indexes. 1638 * 1639 * @return bool 1640 */ 1641 public function is_fulltext_search_supported() { 1642 return true; 1643 } 1644 }
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