Merge "Don't pass USE INDEX to a $dbType parameter" into REL1_31
[lhc/web/wiklou.git] / includes / libs / rdbms / database / IDatabase.php
1 <?php
2 /**
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
16 * http://www.gnu.org/copyleft/gpl.html
17 *
18 * @file
19 */
20 namespace Wikimedia\Rdbms;
21
22 use InvalidArgumentException;
23 use Wikimedia\ScopedCallback;
24 use RuntimeException;
25 use stdClass;
26
27 /**
28 * @defgroup Database Database
29 * This group deals with database interface functions
30 * and query specifics/optimisations.
31 */
32 /**
33 * Basic database interface for live and lazy-loaded relation database handles
34 *
35 * @note: IDatabase and DBConnRef should be updated to reflect any changes
36 * @ingroup Database
37 */
38 interface IDatabase {
39 /** @var int Callback triggered immediately due to no active transaction */
40 const TRIGGER_IDLE = 1;
41 /** @var int Callback triggered by COMMIT */
42 const TRIGGER_COMMIT = 2;
43 /** @var int Callback triggered by ROLLBACK */
44 const TRIGGER_ROLLBACK = 3;
45
46 /** @var string Transaction is requested by regular caller outside of the DB layer */
47 const TRANSACTION_EXPLICIT = '';
48 /** @var string Transaction is requested internally via DBO_TRX/startAtomic() */
49 const TRANSACTION_INTERNAL = 'implicit';
50
51 /** @var string Atomic section is not cancelable */
52 const ATOMIC_NOT_CANCELABLE = '';
53 /** @var string Atomic section is cancelable */
54 const ATOMIC_CANCELABLE = 'cancelable';
55
56 /** @var string Commit/rollback is from outside the IDatabase handle and connection manager */
57 const FLUSHING_ONE = '';
58 /** @var string Commit/rollback is from the connection manager for the IDatabase handle */
59 const FLUSHING_ALL_PEERS = 'flush';
60 /** @var string Commit/rollback is from the IDatabase handle internally */
61 const FLUSHING_INTERNAL = 'flush';
62
63 /** @var string Do not remember the prior flags */
64 const REMEMBER_NOTHING = '';
65 /** @var string Remember the prior flags */
66 const REMEMBER_PRIOR = 'remember';
67 /** @var string Restore to the prior flag state */
68 const RESTORE_PRIOR = 'prior';
69 /** @var string Restore to the initial flag state */
70 const RESTORE_INITIAL = 'initial';
71
72 /** @var string Estimate total time (RTT, scanning, waiting on locks, applying) */
73 const ESTIMATE_TOTAL = 'total';
74 /** @var string Estimate time to apply (scanning, applying) */
75 const ESTIMATE_DB_APPLY = 'apply';
76
77 /** @var int Combine list with comma delimeters */
78 const LIST_COMMA = 0;
79 /** @var int Combine list with AND clauses */
80 const LIST_AND = 1;
81 /** @var int Convert map into a SET clause */
82 const LIST_SET = 2;
83 /** @var int Treat as field name and do not apply value escaping */
84 const LIST_NAMES = 3;
85 /** @var int Combine list with OR clauses */
86 const LIST_OR = 4;
87
88 /** @var int Enable debug logging */
89 const DBO_DEBUG = 1;
90 /** @var int Disable query buffering (only one result set can be iterated at a time) */
91 const DBO_NOBUFFER = 2;
92 /** @var int Ignore query errors (internal use only!) */
93 const DBO_IGNORE = 4;
94 /** @var int Automatically start a transaction before running a query if none is active */
95 const DBO_TRX = 8;
96 /** @var int Use DBO_TRX in non-CLI mode */
97 const DBO_DEFAULT = 16;
98 /** @var int Use DB persistent connections if possible */
99 const DBO_PERSISTENT = 32;
100 /** @var int DBA session mode; mostly for Oracle */
101 const DBO_SYSDBA = 64;
102 /** @var int Schema file mode; mostly for Oracle */
103 const DBO_DDLMODE = 128;
104 /** @var int Enable SSL/TLS in connection protocol */
105 const DBO_SSL = 256;
106 /** @var int Enable compression in connection protocol */
107 const DBO_COMPRESS = 512;
108
109 /**
110 * A string describing the current software version, and possibly
111 * other details in a user-friendly way. Will be listed on Special:Version, etc.
112 * Use getServerVersion() to get machine-friendly information.
113 *
114 * @return string Version information from the database server
115 */
116 public function getServerInfo();
117
118 /**
119 * Turns buffering of SQL result sets on (true) or off (false). Default is "on".
120 *
121 * Unbuffered queries are very troublesome in MySQL:
122 *
123 * - If another query is executed while the first query is being read
124 * out, the first query is killed. This means you can't call normal
125 * Database functions while you are reading an unbuffered query result
126 * from a normal Database connection.
127 *
128 * - Unbuffered queries cause the MySQL server to use large amounts of
129 * memory and to hold broad locks which block other queries.
130 *
131 * If you want to limit client-side memory, it's almost always better to
132 * split up queries into batches using a LIMIT clause than to switch off
133 * buffering.
134 *
135 * @param null|bool $buffer
136 * @return null|bool The previous value of the flag
137 */
138 public function bufferResults( $buffer = null );
139
140 /**
141 * Gets the current transaction level.
142 *
143 * Historically, transactions were allowed to be "nested". This is no
144 * longer supported, so this function really only returns a boolean.
145 *
146 * @return int The previous value
147 */
148 public function trxLevel();
149
150 /**
151 * Get the UNIX timestamp of the time that the transaction was established
152 *
153 * This can be used to reason about the staleness of SELECT data
154 * in REPEATABLE-READ transaction isolation level.
155 *
156 * @return float|null Returns null if there is not active transaction
157 * @since 1.25
158 */
159 public function trxTimestamp();
160
161 /**
162 * @return bool Whether an explicit transaction or atomic sections are still open
163 * @since 1.28
164 */
165 public function explicitTrxActive();
166
167 /**
168 * Get/set the table prefix.
169 * @param string $prefix The table prefix to set, or omitted to leave it unchanged.
170 * @return string The previous table prefix.
171 */
172 public function tablePrefix( $prefix = null );
173
174 /**
175 * Get/set the db schema.
176 * @param string $schema The database schema to set, or omitted to leave it unchanged.
177 * @return string The previous db schema.
178 */
179 public function dbSchema( $schema = null );
180
181 /**
182 * Get properties passed down from the server info array of the load
183 * balancer.
184 *
185 * @param string $name The entry of the info array to get, or null to get the
186 * whole array
187 *
188 * @return array|mixed|null
189 */
190 public function getLBInfo( $name = null );
191
192 /**
193 * Set the LB info array, or a member of it. If called with one parameter,
194 * the LB info array is set to that parameter. If it is called with two
195 * parameters, the member with the given name is set to the given value.
196 *
197 * @param string $name
198 * @param array $value
199 */
200 public function setLBInfo( $name, $value = null );
201
202 /**
203 * Set a lazy-connecting DB handle to the master DB (for replication status purposes)
204 *
205 * @param IDatabase $conn
206 * @since 1.27
207 */
208 public function setLazyMasterHandle( IDatabase $conn );
209
210 /**
211 * Returns true if this database does an implicit sort when doing GROUP BY
212 *
213 * @return bool
214 * @deprecated Since 1.30; only use grouped or aggregated fields in the SELECT
215 */
216 public function implicitGroupby();
217
218 /**
219 * Returns true if this database does an implicit order by when the column has an index
220 * For example: SELECT page_title FROM page LIMIT 1
221 *
222 * @return bool
223 */
224 public function implicitOrderby();
225
226 /**
227 * Return the last query that went through IDatabase::query()
228 * @return string
229 */
230 public function lastQuery();
231
232 /**
233 * Returns true if the connection may have been used for write queries.
234 * Should return true if unsure.
235 *
236 * @return bool
237 * @deprecated Since 1.31; use lastDoneWrites()
238 */
239 public function doneWrites();
240
241 /**
242 * Returns the last time the connection may have been used for write queries.
243 * Should return a timestamp if unsure.
244 *
245 * @return int|float UNIX timestamp or false
246 * @since 1.24
247 */
248 public function lastDoneWrites();
249
250 /**
251 * @return bool Whether there is a transaction open with possible write queries
252 * @since 1.27
253 */
254 public function writesPending();
255
256 /**
257 * Returns true if there is a transaction/round open with possible write
258 * queries or transaction pre-commit/idle callbacks waiting on it to finish.
259 * This does *not* count recurring callbacks, e.g. from setTransactionListener().
260 *
261 * @return bool
262 */
263 public function writesOrCallbacksPending();
264
265 /**
266 * Get the time spend running write queries for this transaction
267 *
268 * High times could be due to scanning, updates, locking, and such
269 *
270 * @param string $type IDatabase::ESTIMATE_* constant [default: ESTIMATE_ALL]
271 * @return float|bool Returns false if not transaction is active
272 * @since 1.26
273 */
274 public function pendingWriteQueryDuration( $type = self::ESTIMATE_TOTAL );
275
276 /**
277 * Get the list of method names that did write queries for this transaction
278 *
279 * @return array
280 * @since 1.27
281 */
282 public function pendingWriteCallers();
283
284 /**
285 * Get the number of affected rows from pending write queries
286 *
287 * @return int
288 * @since 1.30
289 */
290 public function pendingWriteRowsAffected();
291
292 /**
293 * Is a connection to the database open?
294 * @return bool
295 */
296 public function isOpen();
297
298 /**
299 * Set a flag for this connection
300 *
301 * @param int $flag DBO_* constants from Defines.php:
302 * - DBO_DEBUG: output some debug info (same as debug())
303 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
304 * - DBO_TRX: automatically start transactions
305 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
306 * and removes it in command line mode
307 * - DBO_PERSISTENT: use persistant database connection
308 * @param string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]
309 */
310 public function setFlag( $flag, $remember = self::REMEMBER_NOTHING );
311
312 /**
313 * Clear a flag for this connection
314 *
315 * @param int $flag DBO_* constants from Defines.php:
316 * - DBO_DEBUG: output some debug info (same as debug())
317 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
318 * - DBO_TRX: automatically start transactions
319 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
320 * and removes it in command line mode
321 * - DBO_PERSISTENT: use persistant database connection
322 * @param string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]
323 */
324 public function clearFlag( $flag, $remember = self::REMEMBER_NOTHING );
325
326 /**
327 * Restore the flags to their prior state before the last setFlag/clearFlag call
328 *
329 * @param string $state IDatabase::RESTORE_* constant. [default: RESTORE_PRIOR]
330 * @since 1.28
331 */
332 public function restoreFlags( $state = self::RESTORE_PRIOR );
333
334 /**
335 * Returns a boolean whether the flag $flag is set for this connection
336 *
337 * @param int $flag DBO_* constants from Defines.php:
338 * - DBO_DEBUG: output some debug info (same as debug())
339 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
340 * - DBO_TRX: automatically start transactions
341 * - DBO_PERSISTENT: use persistant database connection
342 * @return bool
343 */
344 public function getFlag( $flag );
345
346 /**
347 * @return string
348 */
349 public function getDomainID();
350
351 /**
352 * Alias for getDomainID()
353 *
354 * @return string
355 * @deprecated 1.30
356 */
357 public function getWikiID();
358
359 /**
360 * Get the type of the DBMS, as it appears in $wgDBtype.
361 *
362 * @return string
363 */
364 public function getType();
365
366 /**
367 * Open a new connection to the database (closing any existing one)
368 *
369 * @param string $server Database server host
370 * @param string $user Database user name
371 * @param string $password Database user password
372 * @param string $dbName Database name
373 * @return bool
374 * @throws DBConnectionError
375 */
376 public function open( $server, $user, $password, $dbName );
377
378 /**
379 * Fetch the next row from the given result object, in object form.
380 * Fields can be retrieved with $row->fieldname, with fields acting like
381 * member variables.
382 * If no more rows are available, false is returned.
383 *
384 * @param IResultWrapper|stdClass $res Object as returned from IDatabase::query(), etc.
385 * @return stdClass|bool
386 * @throws DBUnexpectedError Thrown if the database returns an error
387 */
388 public function fetchObject( $res );
389
390 /**
391 * Fetch the next row from the given result object, in associative array
392 * form. Fields are retrieved with $row['fieldname'].
393 * If no more rows are available, false is returned.
394 *
395 * @param IResultWrapper $res Result object as returned from IDatabase::query(), etc.
396 * @return array|bool
397 * @throws DBUnexpectedError Thrown if the database returns an error
398 */
399 public function fetchRow( $res );
400
401 /**
402 * Get the number of rows in a result object
403 *
404 * @param mixed $res A SQL result
405 * @return int
406 */
407 public function numRows( $res );
408
409 /**
410 * Get the number of fields in a result object
411 * @see https://secure.php.net/mysql_num_fields
412 *
413 * @param mixed $res A SQL result
414 * @return int
415 */
416 public function numFields( $res );
417
418 /**
419 * Get a field name in a result object
420 * @see https://secure.php.net/mysql_field_name
421 *
422 * @param mixed $res A SQL result
423 * @param int $n
424 * @return string
425 */
426 public function fieldName( $res, $n );
427
428 /**
429 * Get the inserted value of an auto-increment row
430 *
431 * This should only be called after an insert that used an auto-incremented
432 * value. If no such insert was previously done in the current database
433 * session, the return value is undefined.
434 *
435 * @return int
436 */
437 public function insertId();
438
439 /**
440 * Change the position of the cursor in a result object
441 * @see https://secure.php.net/mysql_data_seek
442 *
443 * @param mixed $res A SQL result
444 * @param int $row
445 */
446 public function dataSeek( $res, $row );
447
448 /**
449 * Get the last error number
450 * @see https://secure.php.net/mysql_errno
451 *
452 * @return int
453 */
454 public function lastErrno();
455
456 /**
457 * Get a description of the last error
458 * @see https://secure.php.net/mysql_error
459 *
460 * @return string
461 */
462 public function lastError();
463
464 /**
465 * Get the number of rows affected by the last write query
466 * @see https://secure.php.net/mysql_affected_rows
467 *
468 * @return int
469 */
470 public function affectedRows();
471
472 /**
473 * Returns a wikitext link to the DB's website, e.g.,
474 * return "[https://www.mysql.com/ MySQL]";
475 * Should at least contain plain text, if for some reason
476 * your database has no website.
477 *
478 * @return string Wikitext of a link to the server software's web site
479 */
480 public function getSoftwareLink();
481
482 /**
483 * A string describing the current software version, like from
484 * mysql_get_server_info().
485 *
486 * @return string Version information from the database server.
487 */
488 public function getServerVersion();
489
490 /**
491 * Close the database connection
492 *
493 * This should only be called after any transactions have been resolved,
494 * aside from read-only transactions (assuming no callbacks are registered).
495 * If a transaction is still open anyway, it will be committed if possible.
496 *
497 * @throws DBError
498 * @return bool Operation success. true if already closed.
499 */
500 public function close();
501
502 /**
503 * Run an SQL query and return the result. Normally throws a DBQueryError
504 * on failure. If errors are ignored, returns false instead.
505 *
506 * If a connection loss is detected, then an attempt to reconnect will be made.
507 * For queries that involve no larger transactions or locks, they will be re-issued
508 * for convenience, provided the connection was re-established.
509 *
510 * In new code, the query wrappers select(), insert(), update(), delete(),
511 * etc. should be used where possible, since they give much better DBMS
512 * independence and automatically quote or validate user input in a variety
513 * of contexts. This function is generally only useful for queries which are
514 * explicitly DBMS-dependent and are unsupported by the query wrappers, such
515 * as CREATE TABLE.
516 *
517 * However, the query wrappers themselves should call this function.
518 *
519 * @param string $sql SQL query
520 * @param string $fname Name of the calling function, for profiling/SHOW PROCESSLIST
521 * comment (you can use __METHOD__ or add some extra info)
522 * @param bool $tempIgnore Whether to avoid throwing an exception on errors...
523 * maybe best to catch the exception instead?
524 * @return bool|IResultWrapper True for a successful write query, IResultWrapper object
525 * for a successful read query, or false on failure if $tempIgnore set
526 * @throws DBError
527 */
528 public function query( $sql, $fname = __METHOD__, $tempIgnore = false );
529
530 /**
531 * Free a result object returned by query() or select(). It's usually not
532 * necessary to call this, just use unset() or let the variable holding
533 * the result object go out of scope.
534 *
535 * @param mixed $res A SQL result
536 */
537 public function freeResult( $res );
538
539 /**
540 * A SELECT wrapper which returns a single field from a single result row.
541 *
542 * Usually throws a DBQueryError on failure. If errors are explicitly
543 * ignored, returns false on failure.
544 *
545 * If no result rows are returned from the query, false is returned.
546 *
547 * @param string|array $table Table name. See IDatabase::select() for details.
548 * @param string $var The field name to select. This must be a valid SQL
549 * fragment: do not use unvalidated user input.
550 * @param string|array $cond The condition array. See IDatabase::select() for details.
551 * @param string $fname The function name of the caller.
552 * @param string|array $options The query options. See IDatabase::select() for details.
553 * @param string|array $join_conds The query join conditions. See IDatabase::select() for details.
554 *
555 * @return mixed The value from the field
556 * @throws DBError
557 */
558 public function selectField(
559 $table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
560 );
561
562 /**
563 * A SELECT wrapper which returns a list of single field values from result rows.
564 *
565 * Usually throws a DBQueryError on failure. If errors are explicitly
566 * ignored, returns false on failure.
567 *
568 * If no result rows are returned from the query, false is returned.
569 *
570 * @param string|array $table Table name. See IDatabase::select() for details.
571 * @param string $var The field name to select. This must be a valid SQL
572 * fragment: do not use unvalidated user input.
573 * @param string|array $cond The condition array. See IDatabase::select() for details.
574 * @param string $fname The function name of the caller.
575 * @param string|array $options The query options. See IDatabase::select() for details.
576 * @param string|array $join_conds The query join conditions. See IDatabase::select() for details.
577 *
578 * @return array The values from the field
579 * @throws DBError
580 * @since 1.25
581 */
582 public function selectFieldValues(
583 $table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
584 );
585
586 /**
587 * Execute a SELECT query constructed using the various parameters provided.
588 * See below for full details of the parameters.
589 *
590 * @param string|array $table Table name
591 * @param string|array $vars Field names
592 * @param string|array $conds Conditions
593 * @param string $fname Caller function name
594 * @param array $options Query options
595 * @param array $join_conds Join conditions
596 *
597 *
598 * @param string|array $table
599 *
600 * May be either an array of table names, or a single string holding a table
601 * name. If an array is given, table aliases can be specified, for example:
602 *
603 * [ 'a' => 'user' ]
604 *
605 * This includes the user table in the query, with the alias "a" available
606 * for use in field names (e.g. a.user_name).
607 *
608 * A derived table, defined by the result of selectSQLText(), requires an alias
609 * key and a Subquery instance value which wraps the SQL query, for example:
610 *
611 * [ 'c' => new Subquery( 'SELECT ...' ) ]
612 *
613 * Joins using parentheses for grouping (since MediaWiki 1.31) may be
614 * constructed using nested arrays. For example,
615 *
616 * [ 'tableA', 'nestedB' => [ 'tableB', 'b2' => 'tableB2' ] ]
617 *
618 * along with `$join_conds` like
619 *
620 * [ 'b2' => [ 'JOIN', 'b_id = b2_id' ], 'nestedB' => [ 'LEFT JOIN', 'b_a = a_id' ] ]
621 *
622 * will produce SQL something like
623 *
624 * FROM tableA LEFT JOIN (tableB JOIN tableB2 AS b2 ON (b_id = b2_id)) ON (b_a = a_id)
625 *
626 * All of the table names given here are automatically run through
627 * Database::tableName(), which causes the table prefix (if any) to be
628 * added, and various other table name mappings to be performed.
629 *
630 * Do not use untrusted user input as a table name. Alias names should
631 * not have characters outside of the Basic multilingual plane.
632 *
633 * @param string|array $vars
634 *
635 * May be either a field name or an array of field names. The field names
636 * can be complete fragments of SQL, for direct inclusion into the SELECT
637 * query. If an array is given, field aliases can be specified, for example:
638 *
639 * [ 'maxrev' => 'MAX(rev_id)' ]
640 *
641 * This includes an expression with the alias "maxrev" in the query.
642 *
643 * If an expression is given, care must be taken to ensure that it is
644 * DBMS-independent.
645 *
646 * Untrusted user input must not be passed to this parameter.
647 *
648 * @param string|array $conds
649 *
650 * May be either a string containing a single condition, or an array of
651 * conditions. If an array is given, the conditions constructed from each
652 * element are combined with AND.
653 *
654 * Array elements may take one of two forms:
655 *
656 * - Elements with a numeric key are interpreted as raw SQL fragments.
657 * - Elements with a string key are interpreted as equality conditions,
658 * where the key is the field name.
659 * - If the value of such an array element is a scalar (such as a
660 * string), it will be treated as data and thus quoted appropriately.
661 * If it is null, an IS NULL clause will be added.
662 * - If the value is an array, an IN (...) clause will be constructed
663 * from its non-null elements, and an IS NULL clause will be added
664 * if null is present, such that the field may match any of the
665 * elements in the array. The non-null elements will be quoted.
666 *
667 * Note that expressions are often DBMS-dependent in their syntax.
668 * DBMS-independent wrappers are provided for constructing several types of
669 * expression commonly used in condition queries. See:
670 * - IDatabase::buildLike()
671 * - IDatabase::conditional()
672 *
673 * Untrusted user input is safe in the values of string keys, however untrusted
674 * input must not be used in the array key names or in the values of numeric keys.
675 * Escaping of untrusted input used in values of numeric keys should be done via
676 * IDatabase::addQuotes()
677 *
678 * @param string|array $options
679 *
680 * Optional: Array of query options. Boolean options are specified by
681 * including them in the array as a string value with a numeric key, for
682 * example:
683 *
684 * [ 'FOR UPDATE' ]
685 *
686 * The supported options are:
687 *
688 * - OFFSET: Skip this many rows at the start of the result set. OFFSET
689 * with LIMIT can theoretically be used for paging through a result set,
690 * but this is discouraged for performance reasons.
691 *
692 * - LIMIT: Integer: return at most this many rows. The rows are sorted
693 * and then the first rows are taken until the limit is reached. LIMIT
694 * is applied to a result set after OFFSET.
695 *
696 * - FOR UPDATE: Boolean: lock the returned rows so that they can't be
697 * changed until the next COMMIT.
698 *
699 * - DISTINCT: Boolean: return only unique result rows.
700 *
701 * - GROUP BY: May be either an SQL fragment string naming a field or
702 * expression to group by, or an array of such SQL fragments.
703 *
704 * - HAVING: May be either an string containing a HAVING clause or an array of
705 * conditions building the HAVING clause. If an array is given, the conditions
706 * constructed from each element are combined with AND.
707 *
708 * - ORDER BY: May be either an SQL fragment giving a field name or
709 * expression to order by, or an array of such SQL fragments.
710 *
711 * - USE INDEX: This may be either a string giving the index name to use
712 * for the query, or an array. If it is an associative array, each key
713 * gives the table name (or alias), each value gives the index name to
714 * use for that table. All strings are SQL fragments and so should be
715 * validated by the caller.
716 *
717 * - EXPLAIN: In MySQL, this causes an EXPLAIN SELECT query to be run,
718 * instead of SELECT.
719 *
720 * And also the following boolean MySQL extensions, see the MySQL manual
721 * for documentation:
722 *
723 * - LOCK IN SHARE MODE
724 * - STRAIGHT_JOIN
725 * - HIGH_PRIORITY
726 * - SQL_BIG_RESULT
727 * - SQL_BUFFER_RESULT
728 * - SQL_SMALL_RESULT
729 * - SQL_CALC_FOUND_ROWS
730 * - SQL_CACHE
731 * - SQL_NO_CACHE
732 *
733 *
734 * @param string|array $join_conds
735 *
736 * Optional associative array of table-specific join conditions. In the
737 * most common case, this is unnecessary, since the join condition can be
738 * in $conds. However, it is useful for doing a LEFT JOIN.
739 *
740 * The key of the array contains the table name or alias. The value is an
741 * array with two elements, numbered 0 and 1. The first gives the type of
742 * join, the second is the same as the $conds parameter. Thus it can be
743 * an SQL fragment, or an array where the string keys are equality and the
744 * numeric keys are SQL fragments all AND'd together. For example:
745 *
746 * [ 'page' => [ 'LEFT JOIN', 'page_latest=rev_id' ] ]
747 *
748 * @return IResultWrapper Resulting rows
749 * @throws DBError
750 */
751 public function select(
752 $table, $vars, $conds = '', $fname = __METHOD__,
753 $options = [], $join_conds = []
754 );
755
756 /**
757 * The equivalent of IDatabase::select() except that the constructed SQL
758 * is returned, instead of being immediately executed. This can be useful for
759 * doing UNION queries, where the SQL text of each query is needed. In general,
760 * however, callers outside of Database classes should just use select().
761 *
762 * @see IDatabase::select()
763 *
764 * @param string|array $table Table name
765 * @param string|array $vars Field names
766 * @param string|array $conds Conditions
767 * @param string $fname Caller function name
768 * @param string|array $options Query options
769 * @param string|array $join_conds Join conditions
770 * @return string SQL query string
771 */
772 public function selectSQLText(
773 $table, $vars, $conds = '', $fname = __METHOD__,
774 $options = [], $join_conds = []
775 );
776
777 /**
778 * Single row SELECT wrapper. Equivalent to IDatabase::select(), except
779 * that a single row object is returned. If the query returns no rows,
780 * false is returned.
781 *
782 * @param string|array $table Table name
783 * @param string|array $vars Field names
784 * @param array $conds Conditions
785 * @param string $fname Caller function name
786 * @param string|array $options Query options
787 * @param array|string $join_conds Join conditions
788 *
789 * @return stdClass|bool
790 * @throws DBError
791 */
792 public function selectRow( $table, $vars, $conds, $fname = __METHOD__,
793 $options = [], $join_conds = []
794 );
795
796 /**
797 * Estimate the number of rows in dataset
798 *
799 * MySQL allows you to estimate the number of rows that would be returned
800 * by a SELECT query, using EXPLAIN SELECT. The estimate is provided using
801 * index cardinality statistics, and is notoriously inaccurate, especially
802 * when large numbers of rows have recently been added or deleted.
803 *
804 * For DBMSs that don't support fast result size estimation, this function
805 * will actually perform the SELECT COUNT(*).
806 *
807 * Takes the same arguments as IDatabase::select().
808 *
809 * @param string $table Table name
810 * @param string $var Column for which NULL values are not counted [default "*"]
811 * @param array|string $conds Filters on the table
812 * @param string $fname Function name for profiling
813 * @param array $options Options for select
814 * @param array|string $join_conds Join conditions
815 * @return int Row count
816 * @throws DBError
817 */
818 public function estimateRowCount(
819 $table, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
820 );
821
822 /**
823 * Get the number of rows in dataset
824 *
825 * This is useful when trying to do COUNT(*) but with a LIMIT for performance.
826 *
827 * Takes the same arguments as IDatabase::select().
828 *
829 * @since 1.27 Added $join_conds parameter
830 *
831 * @param array|string $tables Table names
832 * @param string $var Column for which NULL values are not counted [default "*"]
833 * @param array|string $conds Filters on the table
834 * @param string $fname Function name for profiling
835 * @param array $options Options for select
836 * @param array $join_conds Join conditions (since 1.27)
837 * @return int Row count
838 * @throws DBError
839 */
840 public function selectRowCount(
841 $tables, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
842 );
843
844 /**
845 * Determines whether a field exists in a table
846 *
847 * @param string $table Table name
848 * @param string $field Filed to check on that table
849 * @param string $fname Calling function name (optional)
850 * @return bool Whether $table has filed $field
851 * @throws DBError
852 */
853 public function fieldExists( $table, $field, $fname = __METHOD__ );
854
855 /**
856 * Determines whether an index exists
857 * Usually throws a DBQueryError on failure
858 * If errors are explicitly ignored, returns NULL on failure
859 *
860 * @param string $table
861 * @param string $index
862 * @param string $fname
863 * @return bool|null
864 * @throws DBError
865 */
866 public function indexExists( $table, $index, $fname = __METHOD__ );
867
868 /**
869 * Query whether a given table exists
870 *
871 * @param string $table
872 * @param string $fname
873 * @return bool
874 * @throws DBError
875 */
876 public function tableExists( $table, $fname = __METHOD__ );
877
878 /**
879 * INSERT wrapper, inserts an array into a table.
880 *
881 * $a may be either:
882 *
883 * - A single associative array. The array keys are the field names, and
884 * the values are the values to insert. The values are treated as data
885 * and will be quoted appropriately. If NULL is inserted, this will be
886 * converted to a database NULL.
887 * - An array with numeric keys, holding a list of associative arrays.
888 * This causes a multi-row INSERT on DBMSs that support it. The keys in
889 * each subarray must be identical to each other, and in the same order.
890 *
891 * Usually throws a DBQueryError on failure. If errors are explicitly ignored,
892 * returns success.
893 *
894 * $options is an array of options, with boolean options encoded as values
895 * with numeric keys, in the same style as $options in
896 * IDatabase::select(). Supported options are:
897 *
898 * - IGNORE: Boolean: if present, duplicate key errors are ignored, and
899 * any rows which cause duplicate key errors are not inserted. It's
900 * possible to determine how many rows were successfully inserted using
901 * IDatabase::affectedRows().
902 *
903 * @param string $table Table name. This will be passed through
904 * Database::tableName().
905 * @param array $a Array of rows to insert
906 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
907 * @param array $options Array of options
908 *
909 * @return bool
910 * @throws DBError
911 */
912 public function insert( $table, $a, $fname = __METHOD__, $options = [] );
913
914 /**
915 * UPDATE wrapper. Takes a condition array and a SET array.
916 *
917 * @param string $table Name of the table to UPDATE. This will be passed through
918 * Database::tableName().
919 * @param array $values An array of values to SET. For each array element,
920 * the key gives the field name, and the value gives the data to set
921 * that field to. The data will be quoted by IDatabase::addQuotes().
922 * Values with integer keys form unquoted SET statements, which can be used for
923 * things like "field = field + 1" or similar computed values.
924 * @param array $conds An array of conditions (WHERE). See
925 * IDatabase::select() for the details of the format of condition
926 * arrays. Use '*' to update all rows.
927 * @param string $fname The function name of the caller (from __METHOD__),
928 * for logging and profiling.
929 * @param array $options An array of UPDATE options, can be:
930 * - IGNORE: Ignore unique key conflicts
931 * - LOW_PRIORITY: MySQL-specific, see MySQL manual.
932 * @return bool
933 * @throws DBError
934 */
935 public function update( $table, $values, $conds, $fname = __METHOD__, $options = [] );
936
937 /**
938 * Makes an encoded list of strings from an array
939 *
940 * These can be used to make conjunctions or disjunctions on SQL condition strings
941 * derived from an array (see IDatabase::select() $conds documentation).
942 *
943 * Example usage:
944 * @code
945 * $sql = $db->makeList( [
946 * 'rev_page' => $id,
947 * $db->makeList( [ 'rev_minor' => 1, 'rev_len' < 500 ], $db::LIST_OR ] )
948 * ], $db::LIST_AND );
949 * @endcode
950 * This would set $sql to "rev_page = '$id' AND (rev_minor = '1' OR rev_len < '500')"
951 *
952 * @param array $a Containing the data
953 * @param int $mode IDatabase class constant:
954 * - IDatabase::LIST_COMMA: Comma separated, no field names
955 * - IDatabase::LIST_AND: ANDed WHERE clause (without the WHERE).
956 * - IDatabase::LIST_OR: ORed WHERE clause (without the WHERE)
957 * - IDatabase::LIST_SET: Comma separated with field names, like a SET clause
958 * - IDatabase::LIST_NAMES: Comma separated field names
959 * @throws DBError
960 * @return string
961 */
962 public function makeList( $a, $mode = self::LIST_COMMA );
963
964 /**
965 * Build a partial where clause from a 2-d array such as used for LinkBatch.
966 * The keys on each level may be either integers or strings.
967 *
968 * @param array $data Organized as 2-d
969 * [ baseKeyVal => [ subKeyVal => [ignored], ... ], ... ]
970 * @param string $baseKey Field name to match the base-level keys to (eg 'pl_namespace')
971 * @param string $subKey Field name to match the sub-level keys to (eg 'pl_title')
972 * @return string|bool SQL fragment, or false if no items in array
973 */
974 public function makeWhereFrom2d( $data, $baseKey, $subKey );
975
976 /**
977 * Return aggregated value alias
978 *
979 * @param array $valuedata
980 * @param string $valuename
981 *
982 * @return string
983 */
984 public function aggregateValue( $valuedata, $valuename = 'value' );
985
986 /**
987 * @param string $field
988 * @return string
989 */
990 public function bitNot( $field );
991
992 /**
993 * @param string $fieldLeft
994 * @param string $fieldRight
995 * @return string
996 */
997 public function bitAnd( $fieldLeft, $fieldRight );
998
999 /**
1000 * @param string $fieldLeft
1001 * @param string $fieldRight
1002 * @return string
1003 */
1004 public function bitOr( $fieldLeft, $fieldRight );
1005
1006 /**
1007 * Build a concatenation list to feed into a SQL query
1008 * @param array $stringList List of raw SQL expressions; caller is
1009 * responsible for any quoting
1010 * @return string
1011 */
1012 public function buildConcat( $stringList );
1013
1014 /**
1015 * Build a GROUP_CONCAT or equivalent statement for a query.
1016 *
1017 * This is useful for combining a field for several rows into a single string.
1018 * NULL values will not appear in the output, duplicated values will appear,
1019 * and the resulting delimiter-separated values have no defined sort order.
1020 * Code using the results may need to use the PHP unique() or sort() methods.
1021 *
1022 * @param string $delim Glue to bind the results together
1023 * @param string|array $table Table name
1024 * @param string $field Field name
1025 * @param string|array $conds Conditions
1026 * @param string|array $join_conds Join conditions
1027 * @return string SQL text
1028 * @since 1.23
1029 */
1030 public function buildGroupConcatField(
1031 $delim, $table, $field, $conds = '', $join_conds = []
1032 );
1033
1034 /**
1035 * Build a SUBSTRING function.
1036 *
1037 * Behavior for non-ASCII values is undefined.
1038 *
1039 * @param string $input Field name
1040 * @param int $startPosition Positive integer
1041 * @param int|null $length Non-negative integer length or null for no limit
1042 * @throws InvalidArgumentException
1043 * @return string SQL text
1044 * @since 1.31
1045 */
1046 public function buildSubString( $input, $startPosition, $length = null );
1047
1048 /**
1049 * @param string $field Field or column to cast
1050 * @return string
1051 * @since 1.28
1052 */
1053 public function buildStringCast( $field );
1054
1055 /**
1056 * @param string $field Field or column to cast
1057 * @return string
1058 * @since 1.31
1059 */
1060 public function buildIntegerCast( $field );
1061
1062 /**
1063 * Equivalent to IDatabase::selectSQLText() except wraps the result in Subqyery
1064 *
1065 * @see IDatabase::selectSQLText()
1066 *
1067 * @param string|array $table Table name
1068 * @param string|array $vars Field names
1069 * @param string|array $conds Conditions
1070 * @param string $fname Caller function name
1071 * @param string|array $options Query options
1072 * @param string|array $join_conds Join conditions
1073 * @return Subquery
1074 * @since 1.31
1075 */
1076 public function buildSelectSubquery(
1077 $table, $vars, $conds = '', $fname = __METHOD__,
1078 $options = [], $join_conds = []
1079 );
1080
1081 /**
1082 * Returns true if DBs are assumed to be on potentially different servers
1083 *
1084 * In systems like mysql/mariadb, different databases can easily be referenced on a single
1085 * connection merely by name, even in a single query via JOIN. On the other hand, Postgres
1086 * treats databases as fully separate, only allowing mechanisms like postgres_fdw to
1087 * effectively "mount" foreign DBs. This is true even among DBs on the same server.
1088 *
1089 * @return bool
1090 * @since 1.29
1091 */
1092 public function databasesAreIndependent();
1093
1094 /**
1095 * Change the current database
1096 *
1097 * @param string $db
1098 * @return bool Success or failure
1099 * @throws DBConnectionError If databasesAreIndependent() is true and an error occurs
1100 */
1101 public function selectDB( $db );
1102
1103 /**
1104 * Get the current DB name
1105 * @return string
1106 */
1107 public function getDBname();
1108
1109 /**
1110 * Get the server hostname or IP address
1111 * @return string
1112 */
1113 public function getServer();
1114
1115 /**
1116 * Adds quotes and backslashes.
1117 *
1118 * @param string|int|null|bool|Blob $s
1119 * @return string|int
1120 */
1121 public function addQuotes( $s );
1122
1123 /**
1124 * LIKE statement wrapper, receives a variable-length argument list with
1125 * parts of pattern to match containing either string literals that will be
1126 * escaped or tokens returned by anyChar() or anyString(). Alternatively,
1127 * the function could be provided with an array of aforementioned
1128 * parameters.
1129 *
1130 * Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns
1131 * a LIKE clause that searches for subpages of 'My page title'.
1132 * Alternatively:
1133 * $pattern = [ 'My_page_title/', $dbr->anyString() ];
1134 * $query .= $dbr->buildLike( $pattern );
1135 *
1136 * @since 1.16
1137 * @return string Fully built LIKE statement
1138 */
1139 public function buildLike();
1140
1141 /**
1142 * Returns a token for buildLike() that denotes a '_' to be used in a LIKE query
1143 *
1144 * @return LikeMatch
1145 */
1146 public function anyChar();
1147
1148 /**
1149 * Returns a token for buildLike() that denotes a '%' to be used in a LIKE query
1150 *
1151 * @return LikeMatch
1152 */
1153 public function anyString();
1154
1155 /**
1156 * Deprecated method, calls should be removed.
1157 *
1158 * This was formerly used for PostgreSQL and Oracle to handle
1159 * self::insertId() auto-incrementing fields. It is no longer necessary
1160 * since DatabasePostgres::insertId() has been reimplemented using
1161 * `lastval()` and Oracle has been reimplemented using triggers.
1162 *
1163 * Implementations should return null if inserting `NULL` into an
1164 * auto-incrementing field works, otherwise it should return an instance of
1165 * NextSequenceValue and filter it on calls to relevant methods.
1166 *
1167 * @deprecated since 1.30, no longer needed
1168 * @param string $seqName
1169 * @return null|NextSequenceValue
1170 */
1171 public function nextSequenceValue( $seqName );
1172
1173 /**
1174 * REPLACE query wrapper.
1175 *
1176 * REPLACE is a very handy MySQL extension, which functions like an INSERT
1177 * except that when there is a duplicate key error, the old row is deleted
1178 * and the new row is inserted in its place.
1179 *
1180 * We simulate this with standard SQL with a DELETE followed by INSERT. To
1181 * perform the delete, we need to know what the unique indexes are so that
1182 * we know how to find the conflicting rows.
1183 *
1184 * It may be more efficient to leave off unique indexes which are unlikely
1185 * to collide. However if you do this, you run the risk of encountering
1186 * errors which wouldn't have occurred in MySQL.
1187 *
1188 * @param string $table The table to replace the row(s) in.
1189 * @param array $uniqueIndexes Is an array of indexes. Each element may be either
1190 * a field name or an array of field names
1191 * @param array $rows Can be either a single row to insert, or multiple rows,
1192 * in the same format as for IDatabase::insert()
1193 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1194 * @throws DBError
1195 */
1196 public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ );
1197
1198 /**
1199 * INSERT ON DUPLICATE KEY UPDATE wrapper, upserts an array into a table.
1200 *
1201 * This updates any conflicting rows (according to the unique indexes) using
1202 * the provided SET clause and inserts any remaining (non-conflicted) rows.
1203 *
1204 * $rows may be either:
1205 * - A single associative array. The array keys are the field names, and
1206 * the values are the values to insert. The values are treated as data
1207 * and will be quoted appropriately. If NULL is inserted, this will be
1208 * converted to a database NULL.
1209 * - An array with numeric keys, holding a list of associative arrays.
1210 * This causes a multi-row INSERT on DBMSs that support it. The keys in
1211 * each subarray must be identical to each other, and in the same order.
1212 *
1213 * It may be more efficient to leave off unique indexes which are unlikely
1214 * to collide. However if you do this, you run the risk of encountering
1215 * errors which wouldn't have occurred in MySQL.
1216 *
1217 * Usually throws a DBQueryError on failure. If errors are explicitly ignored,
1218 * returns success.
1219 *
1220 * @since 1.22
1221 *
1222 * @param string $table Table name. This will be passed through Database::tableName().
1223 * @param array $rows A single row or list of rows to insert
1224 * @param array $uniqueIndexes List of single field names or field name tuples
1225 * @param array $set An array of values to SET. For each array element, the
1226 * key gives the field name, and the value gives the data to set that
1227 * field to. The data will be quoted by IDatabase::addQuotes().
1228 * Values with integer keys form unquoted SET statements, which can be used for
1229 * things like "field = field + 1" or similar computed values.
1230 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1231 * @throws DBError
1232 * @return bool
1233 */
1234 public function upsert(
1235 $table, array $rows, array $uniqueIndexes, array $set, $fname = __METHOD__
1236 );
1237
1238 /**
1239 * DELETE where the condition is a join.
1240 *
1241 * MySQL overrides this to use a multi-table DELETE syntax, in other databases
1242 * we use sub-selects
1243 *
1244 * For safety, an empty $conds will not delete everything. If you want to
1245 * delete all rows where the join condition matches, set $conds='*'.
1246 *
1247 * DO NOT put the join condition in $conds.
1248 *
1249 * @param string $delTable The table to delete from.
1250 * @param string $joinTable The other table.
1251 * @param string $delVar The variable to join on, in the first table.
1252 * @param string $joinVar The variable to join on, in the second table.
1253 * @param array $conds Condition array of field names mapped to variables,
1254 * ANDed together in the WHERE clause
1255 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1256 * @throws DBError
1257 */
1258 public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
1259 $fname = __METHOD__
1260 );
1261
1262 /**
1263 * DELETE query wrapper.
1264 *
1265 * @param string $table Table name
1266 * @param string|array $conds Array of conditions. See $conds in IDatabase::select()
1267 * for the format. Use $conds == "*" to delete all rows
1268 * @param string $fname Name of the calling function
1269 * @throws DBUnexpectedError
1270 * @return bool|IResultWrapper
1271 * @throws DBError
1272 */
1273 public function delete( $table, $conds, $fname = __METHOD__ );
1274
1275 /**
1276 * INSERT SELECT wrapper. Takes data from a SELECT query and inserts it
1277 * into another table.
1278 *
1279 * @warning If the insert will use an auto-increment or sequence to
1280 * determine the value of a column, this may break replication on
1281 * databases using statement-based replication if the SELECT is not
1282 * deterministically ordered.
1283 *
1284 * @param string $destTable The table name to insert into
1285 * @param string|array $srcTable May be either a table name, or an array of table names
1286 * to include in a join.
1287 *
1288 * @param array $varMap Must be an associative array of the form
1289 * [ 'dest1' => 'source1', ... ]. Source items may be literals
1290 * rather than field names, but strings should be quoted with
1291 * IDatabase::addQuotes()
1292 *
1293 * @param array $conds Condition array. See $conds in IDatabase::select() for
1294 * the details of the format of condition arrays. May be "*" to copy the
1295 * whole table.
1296 *
1297 * @param string $fname The function name of the caller, from __METHOD__
1298 *
1299 * @param array $insertOptions Options for the INSERT part of the query, see
1300 * IDatabase::insert() for details. Also, one additional option is
1301 * available: pass 'NO_AUTO_COLUMNS' to hint that the query does not use
1302 * an auto-increment or sequence to determine any column values.
1303 * @param array $selectOptions Options for the SELECT part of the query, see
1304 * IDatabase::select() for details.
1305 * @param array $selectJoinConds Join conditions for the SELECT part of the query, see
1306 * IDatabase::select() for details.
1307 *
1308 * @return bool
1309 * @throws DBError
1310 */
1311 public function insertSelect( $destTable, $srcTable, $varMap, $conds,
1312 $fname = __METHOD__,
1313 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
1314 );
1315
1316 /**
1317 * Returns true if current database backend supports ORDER BY or LIMIT for separate subqueries
1318 * within the UNION construct.
1319 * @return bool
1320 */
1321 public function unionSupportsOrderAndLimit();
1322
1323 /**
1324 * Construct a UNION query
1325 * This is used for providing overload point for other DB abstractions
1326 * not compatible with the MySQL syntax.
1327 * @param array $sqls SQL statements to combine
1328 * @param bool $all Use UNION ALL
1329 * @return string SQL fragment
1330 */
1331 public function unionQueries( $sqls, $all );
1332
1333 /**
1334 * Construct a UNION query for permutations of conditions
1335 *
1336 * Databases sometimes have trouble with queries that have multiple values
1337 * for multiple condition parameters combined with limits and ordering.
1338 * This method constructs queries for the Cartesian product of the
1339 * conditions and unions them all together.
1340 *
1341 * @see IDatabase::select()
1342 * @since 1.30
1343 * @param string|array $table Table name
1344 * @param string|array $vars Field names
1345 * @param array $permute_conds Conditions for the Cartesian product. Keys
1346 * are field names, values are arrays of the possible values for that
1347 * field.
1348 * @param string|array $extra_conds Additional conditions to include in the
1349 * query.
1350 * @param string $fname Caller function name
1351 * @param string|array $options Query options. In addition to the options
1352 * recognized by IDatabase::select(), the following may be used:
1353 * - NOTALL: Set to use UNION instead of UNION ALL.
1354 * - INNER ORDER BY: If specified and supported, subqueries will use this
1355 * instead of ORDER BY.
1356 * @param string|array $join_conds Join conditions
1357 * @return string SQL query string.
1358 */
1359 public function unionConditionPermutations(
1360 $table, $vars, array $permute_conds, $extra_conds = '', $fname = __METHOD__,
1361 $options = [], $join_conds = []
1362 );
1363
1364 /**
1365 * Returns an SQL expression for a simple conditional. This doesn't need
1366 * to be overridden unless CASE isn't supported in your DBMS.
1367 *
1368 * @param string|array $cond SQL expression which will result in a boolean value
1369 * @param string $trueVal SQL expression to return if true
1370 * @param string $falseVal SQL expression to return if false
1371 * @return string SQL fragment
1372 */
1373 public function conditional( $cond, $trueVal, $falseVal );
1374
1375 /**
1376 * Returns a command for str_replace function in SQL query.
1377 * Uses REPLACE() in MySQL
1378 *
1379 * @param string $orig Column to modify
1380 * @param string $old Column to seek
1381 * @param string $new Column to replace with
1382 *
1383 * @return string
1384 */
1385 public function strreplace( $orig, $old, $new );
1386
1387 /**
1388 * Determines how long the server has been up
1389 *
1390 * @return int
1391 * @throws DBError
1392 */
1393 public function getServerUptime();
1394
1395 /**
1396 * Determines if the last failure was due to a deadlock
1397 *
1398 * Note that during a deadlock, the prior transaction will have been lost
1399 *
1400 * @return bool
1401 */
1402 public function wasDeadlock();
1403
1404 /**
1405 * Determines if the last failure was due to a lock timeout
1406 *
1407 * Note that during a lock wait timeout, the prior transaction will have been lost
1408 *
1409 * @return bool
1410 */
1411 public function wasLockTimeout();
1412
1413 /**
1414 * Determines if the last query error was due to a dropped connection
1415 *
1416 * Note that during a connection loss, the prior transaction will have been lost
1417 *
1418 * @return bool
1419 * @since 1.31
1420 */
1421 public function wasConnectionLoss();
1422
1423 /**
1424 * Determines if the last failure was due to the database being read-only.
1425 *
1426 * @return bool
1427 */
1428 public function wasReadOnlyError();
1429
1430 /**
1431 * Determines if the last query error was due to something outside of the query itself
1432 *
1433 * Note that the transaction may have been lost, discarding prior writes and results
1434 *
1435 * @return bool
1436 */
1437 public function wasErrorReissuable();
1438
1439 /**
1440 * Wait for the replica DB to catch up to a given master position
1441 *
1442 * @param DBMasterPos $pos
1443 * @param int $timeout The maximum number of seconds to wait for synchronisation
1444 * @return int|null Zero if the replica DB was past that position already,
1445 * greater than zero if we waited for some period of time, less than
1446 * zero if it timed out, and null on error
1447 * @throws DBError
1448 */
1449 public function masterPosWait( DBMasterPos $pos, $timeout );
1450
1451 /**
1452 * Get the replication position of this replica DB
1453 *
1454 * @return DBMasterPos|bool False if this is not a replica DB
1455 * @throws DBError
1456 */
1457 public function getReplicaPos();
1458
1459 /**
1460 * Get the position of this master
1461 *
1462 * @return DBMasterPos|bool False if this is not a master
1463 * @throws DBError
1464 */
1465 public function getMasterPos();
1466
1467 /**
1468 * @return bool Whether the DB is marked as read-only server-side
1469 * @since 1.28
1470 */
1471 public function serverIsReadOnly();
1472
1473 /**
1474 * Run a callback as soon as the current transaction commits or rolls back.
1475 * An error is thrown if no transaction is pending. Queries in the function will run in
1476 * AUTOCOMMIT mode unless there are begin() calls. Callbacks must commit any transactions
1477 * that they begin.
1478 *
1479 * This is useful for combining cooperative locks and DB transactions.
1480 *
1481 * @note: do not assume that *other* IDatabase instances will be AUTOCOMMIT mode
1482 *
1483 * The callback takes one argument:
1484 * - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK)
1485 *
1486 * @param callable $callback
1487 * @param string $fname Caller name
1488 * @return mixed
1489 * @since 1.28
1490 */
1491 public function onTransactionResolution( callable $callback, $fname = __METHOD__ );
1492
1493 /**
1494 * Run a callback as soon as there is no transaction pending.
1495 * If there is a transaction and it is rolled back, then the callback is cancelled.
1496 *
1497 * When transaction round mode (DBO_TRX) is set, the callback will run at the end
1498 * of the round, just after all peer transactions COMMIT. If the transaction round
1499 * is rolled back, then the callback is cancelled.
1500 *
1501 * Queries in the function will run in AUTOCOMMIT mode unless there are begin() calls.
1502 * Callbacks must commit any transactions that they begin.
1503 *
1504 * This is useful for updates to different systems or when separate transactions are needed.
1505 * For example, one might want to enqueue jobs into a system outside the database, but only
1506 * after the database is updated so that the jobs will see the data when they actually run.
1507 * It can also be used for updates that easily suffer from lock timeouts and deadlocks,
1508 * but where atomicity is not essential.
1509 *
1510 * Updates will execute in the order they were enqueued.
1511 *
1512 * @note: do not assume that *other* IDatabase instances will be AUTOCOMMIT mode
1513 *
1514 * The callback takes one argument:
1515 * - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_IDLE)
1516 *
1517 * @param callable $callback
1518 * @param string $fname Caller name
1519 * @since 1.20
1520 */
1521 public function onTransactionIdle( callable $callback, $fname = __METHOD__ );
1522
1523 /**
1524 * Run a callback before the current transaction commits or now if there is none.
1525 * If there is a transaction and it is rolled back, then the callback is cancelled.
1526 *
1527 * When transaction round mode (DBO_TRX) is set, the callback will run at the end
1528 * of the round, just before all peer transactions COMMIT. If the transaction round
1529 * is rolled back, then the callback is cancelled.
1530 *
1531 * Callbacks must not start nor commit any transactions. If no transaction is active,
1532 * then a transaction will wrap the callback.
1533 *
1534 * This is useful for updates that easily suffer from lock timeouts and deadlocks,
1535 * but where atomicity is strongly desired for these updates and some related updates.
1536 *
1537 * Updates will execute in the order they were enqueued.
1538 *
1539 * @param callable $callback
1540 * @param string $fname Caller name
1541 * @since 1.22
1542 */
1543 public function onTransactionPreCommitOrIdle( callable $callback, $fname = __METHOD__ );
1544
1545 /**
1546 * Run a callback each time any transaction commits or rolls back
1547 *
1548 * The callback takes two arguments:
1549 * - IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK
1550 * - This IDatabase object
1551 * Callbacks must commit any transactions that they begin.
1552 *
1553 * Registering a callback here will not affect writesOrCallbacks() pending
1554 *
1555 * @param string $name Callback name
1556 * @param callable|null $callback Use null to unset a listener
1557 * @return mixed
1558 * @since 1.28
1559 */
1560 public function setTransactionListener( $name, callable $callback = null );
1561
1562 /**
1563 * Begin an atomic section of SQL statements
1564 *
1565 * Start an implicit transaction if no transaction is already active, set a savepoint
1566 * (if $cancelable is ATOMIC_CANCELABLE), and track the given section name to enforce
1567 * that the transaction is not committed prematurely. The end of the section must be
1568 * signified exactly once, either by endAtomic() or cancelAtomic(). Sections can have
1569 * have layers of inner sections (sub-sections), but all sections must be ended in order
1570 * of innermost to outermost. Transactions cannot be started or committed until all
1571 * atomic sections are closed.
1572 *
1573 * ATOMIC_CANCELABLE is useful when the caller needs to handle specific failure cases
1574 * by discarding the section's writes. This should not be used for failures when:
1575 * - upsert() could easily be used instead
1576 * - insert() with IGNORE could easily be used instead
1577 * - select() with FOR UPDATE could be checked before issuing writes instead
1578 * - The failure is from code that runs after the first write but doesn't need to
1579 * - The failures are from contention solvable via onTransactionPreCommitOrIdle()
1580 * - The failures are deadlocks; the RDBMs usually discard the whole transaction
1581 *
1582 * @note: callers must use additional measures for situations involving two or more
1583 * (peer) transactions (e.g. updating two database servers at once). The transaction
1584 * and savepoint logic of this method only applies to this specific IDatabase instance.
1585 *
1586 * Example usage:
1587 * @code
1588 * // Start a transaction if there isn't one already
1589 * $dbw->startAtomic( __METHOD__ );
1590 * // Serialize these thread table updates
1591 * $dbw->select( 'thread', '1', [ 'td_id' => $tid ], __METHOD__, 'FOR UPDATE' );
1592 * // Add a new comment for the thread
1593 * $dbw->insert( 'comment', $row, __METHOD__ );
1594 * $cid = $db->insertId();
1595 * // Update thread reference to last comment
1596 * $dbw->update( 'thread', [ 'td_latest' => $cid ], [ 'td_id' => $tid ], __METHOD__ );
1597 * // Demark the end of this conceptual unit of updates
1598 * $dbw->endAtomic( __METHOD__ );
1599 * @endcode
1600 *
1601 * Example usage (atomic changes that might have to be discarded):
1602 * @code
1603 * // Start a transaction if there isn't one already
1604 * $dbw->startAtomic( __METHOD__, $dbw::ATOMIC_CANCELABLE );
1605 * // Create new record metadata row
1606 * $dbw->insert( 'records', $row, __METHOD__ );
1607 * // Figure out where to store the data based on the new row's ID
1608 * $path = $recordDirectory . '/' . $dbw->insertId();
1609 * // Write the record data to the storage system
1610 * $status = $fileBackend->create( [ 'dst' => $path, 'content' => $data ] );
1611 * if ( $status->isOK() ) {
1612 * // Try to cleanup files orphaned by transaction rollback
1613 * $dbw->onTransactionResolution(
1614 * function ( $type ) use ( $fileBackend, $path ) {
1615 * if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
1616 * $fileBackend->delete( [ 'src' => $path ] );
1617 * }
1618 * },
1619 * __METHOD__
1620 * );
1621 * // Demark the end of this conceptual unit of updates
1622 * $dbw->endAtomic( __METHOD__ );
1623 * } else {
1624 * // Discard these writes from the transaction (preserving prior writes)
1625 * $dbw->cancelAtomic( __METHOD__ );
1626 * }
1627 * @endcode
1628 *
1629 * @since 1.23
1630 * @param string $fname
1631 * @param string $cancelable Pass self::ATOMIC_CANCELABLE to use a
1632 * savepoint and enable self::cancelAtomic() for this section.
1633 * @return AtomicSectionIdentifier section ID token
1634 * @throws DBError
1635 */
1636 public function startAtomic( $fname = __METHOD__, $cancelable = self::ATOMIC_NOT_CANCELABLE );
1637
1638 /**
1639 * Ends an atomic section of SQL statements
1640 *
1641 * Ends the next section of atomic SQL statements and commits the transaction
1642 * if necessary.
1643 *
1644 * @since 1.23
1645 * @see IDatabase::startAtomic
1646 * @param string $fname
1647 * @throws DBError
1648 */
1649 public function endAtomic( $fname = __METHOD__ );
1650
1651 /**
1652 * Cancel an atomic section of SQL statements
1653 *
1654 * This will roll back only the statements executed since the start of the
1655 * most recent atomic section, and close that section. If a transaction was
1656 * open before the corresponding startAtomic() call, any statements before
1657 * that call are *not* rolled back and the transaction remains open. If the
1658 * corresponding startAtomic() implicitly started a transaction, that
1659 * transaction is rolled back.
1660 *
1661 * @note: callers must use additional measures for situations involving two or more
1662 * (peer) transactions (e.g. updating two database servers at once). The transaction
1663 * and savepoint logic of startAtomic() are bound to specific IDatabase instances.
1664 *
1665 * Note that a call to IDatabase::rollback() will also roll back any open atomic sections.
1666 *
1667 * @note As a micro-optimization to save a few DB calls, this method may only
1668 * be called when startAtomic() was called with the ATOMIC_CANCELABLE flag.
1669 * @since 1.31
1670 * @see IDatabase::startAtomic
1671 * @param string $fname
1672 * @param AtomicSectionIdentifier $sectionId Section ID from startAtomic();
1673 * passing this enables cancellation of unclosed nested sections [optional]
1674 * @throws DBError
1675 */
1676 public function cancelAtomic( $fname = __METHOD__, AtomicSectionIdentifier $sectionId = null );
1677
1678 /**
1679 * Perform an atomic section of reversable SQL statements from a callback
1680 *
1681 * The $callback takes the following arguments:
1682 * - This database object
1683 * - The value of $fname
1684 *
1685 * This will execute the callback inside a pair of startAtomic()/endAtomic() calls.
1686 * If any exception occurs during execution of the callback, it will be handled as follows:
1687 * - If $cancelable is ATOMIC_CANCELABLE, cancelAtomic() will be called to back out any
1688 * (and only) statements executed during the atomic section. If that succeeds, then the
1689 * exception will be re-thrown; if it fails, then a different exception will be thrown
1690 * and any further query attempts will fail until rollback() is called.
1691 * - If $cancelable is ATOMIC_NOT_CANCELABLE, cancelAtomic() will be called to mark the
1692 * end of the section and the error will be re-thrown. Any further query attempts will
1693 * fail until rollback() is called.
1694 *
1695 * This method is convenient for letting calls to the caller of this method be wrapped
1696 * in a try/catch blocks for exception types that imply that the caller failed but was
1697 * able to properly discard the changes it made in the transaction. This method can be
1698 * an alternative to explicit calls to startAtomic()/endAtomic()/cancelAtomic().
1699 *
1700 * Example usage, "RecordStore::save" method:
1701 * @code
1702 * $dbw->doAtomicSection( __METHOD__, function ( $dbw ) use ( $record ) {
1703 * // Create new record metadata row
1704 * $dbw->insert( 'records', $record->toArray(), __METHOD__ );
1705 * // Figure out where to store the data based on the new row's ID
1706 * $path = $this->recordDirectory . '/' . $dbw->insertId();
1707 * // Write the record data to the storage system;
1708 * // blob store throughs StoreFailureException on failure
1709 * $this->blobStore->create( $path, $record->getJSON() );
1710 * // Try to cleanup files orphaned by transaction rollback
1711 * $dbw->onTransactionResolution(
1712 * function ( $type ) use ( $path ) {
1713 * if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
1714 * $this->blobStore->delete( $path );
1715 * }
1716 * },
1717 * },
1718 * __METHOD__
1719 * );
1720 * @endcode
1721 *
1722 * Example usage, caller of the "RecordStore::save" method:
1723 * @code
1724 * $dbw->startAtomic( __METHOD__ );
1725 * // ...various SQL writes happen...
1726 * try {
1727 * $recordStore->save( $record );
1728 * } catch ( StoreFailureException $e ) {
1729 * $dbw->cancelAtomic( __METHOD__ );
1730 * // ...various SQL writes happen...
1731 * }
1732 * // ...various SQL writes happen...
1733 * $dbw->endAtomic( __METHOD__ );
1734 * @endcode
1735 *
1736 * @see Database::startAtomic
1737 * @see Database::endAtomic
1738 * @see Database::cancelAtomic
1739 *
1740 * @param string $fname Caller name (usually __METHOD__)
1741 * @param callable $callback Callback that issues DB updates
1742 * @param string $cancelable Pass self::ATOMIC_CANCELABLE to use a
1743 * savepoint and enable self::cancelAtomic() for this section.
1744 * @return mixed $res Result of the callback (since 1.28)
1745 * @throws DBError
1746 * @throws RuntimeException
1747 * @since 1.27; prior to 1.31 this did a rollback() instead of
1748 * cancelAtomic(), and assumed no callers up the stack would ever try to
1749 * catch the exception.
1750 */
1751 public function doAtomicSection(
1752 $fname, callable $callback, $cancelable = self::ATOMIC_NOT_CANCELABLE
1753 );
1754
1755 /**
1756 * Begin a transaction. If a transaction is already in progress,
1757 * that transaction will be committed before the new transaction is started.
1758 *
1759 * Only call this from code with outer transcation scope.
1760 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1761 * Nesting of transactions is not supported.
1762 *
1763 * Note that when the DBO_TRX flag is set (which is usually the case for web
1764 * requests, but not for maintenance scripts), any previous database query
1765 * will have started a transaction automatically.
1766 *
1767 * Nesting of transactions is not supported. Attempts to nest transactions
1768 * will cause a warning, unless the current transaction was started
1769 * automatically because of the DBO_TRX flag.
1770 *
1771 * @param string $fname Calling function name
1772 * @param string $mode A situationally valid IDatabase::TRANSACTION_* constant [optional]
1773 * @throws DBError
1774 */
1775 public function begin( $fname = __METHOD__, $mode = self::TRANSACTION_EXPLICIT );
1776
1777 /**
1778 * Commits a transaction previously started using begin().
1779 * If no transaction is in progress, a warning is issued.
1780 *
1781 * Only call this from code with outer transcation scope.
1782 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1783 * Nesting of transactions is not supported.
1784 *
1785 * @param string $fname
1786 * @param string $flush Flush flag, set to situationally valid IDatabase::FLUSHING_*
1787 * constant to disable warnings about explicitly committing implicit transactions,
1788 * or calling commit when no transaction is in progress.
1789 *
1790 * This will trigger an exception if there is an ongoing explicit transaction.
1791 *
1792 * Only set the flush flag if you are sure that these warnings are not applicable,
1793 * and no explicit transactions are open.
1794 *
1795 * @throws DBError
1796 */
1797 public function commit( $fname = __METHOD__, $flush = '' );
1798
1799 /**
1800 * Rollback a transaction previously started using begin().
1801 * If no transaction is in progress, a warning is issued.
1802 *
1803 * Only call this from code with outer transcation scope.
1804 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1805 * Nesting of transactions is not supported. If a serious unexpected error occurs,
1806 * throwing an Exception is preferrable, using a pre-installed error handler to trigger
1807 * rollback (in any case, failure to issue COMMIT will cause rollback server-side).
1808 *
1809 * Query, connection, and onTransaction* callback errors will be suppressed and logged.
1810 *
1811 * @param string $fname Calling function name
1812 * @param string $flush Flush flag, set to a situationally valid IDatabase::FLUSHING_*
1813 * constant to disable warnings about calling rollback when no transaction is in
1814 * progress. This will silently break any ongoing explicit transaction. Only set the
1815 * flush flag if you are sure that it is safe to ignore these warnings in your context.
1816 * @throws DBError
1817 * @since 1.23 Added $flush parameter
1818 */
1819 public function rollback( $fname = __METHOD__, $flush = '' );
1820
1821 /**
1822 * Commit any transaction but error out if writes or callbacks are pending
1823 *
1824 * This is intended for clearing out REPEATABLE-READ snapshots so that callers can
1825 * see a new point-in-time of the database. This is useful when one of many transaction
1826 * rounds finished and significant time will pass in the script's lifetime. It is also
1827 * useful to call on a replica DB after waiting on replication to catch up to the master.
1828 *
1829 * @param string $fname Calling function name
1830 * @throws DBError
1831 * @since 1.28
1832 */
1833 public function flushSnapshot( $fname = __METHOD__ );
1834
1835 /**
1836 * Convert a timestamp in one of the formats accepted by wfTimestamp()
1837 * to the format used for inserting into timestamp fields in this DBMS.
1838 *
1839 * The result is unquoted, and needs to be passed through addQuotes()
1840 * before it can be included in raw SQL.
1841 *
1842 * @param string|int $ts
1843 *
1844 * @return string
1845 */
1846 public function timestamp( $ts = 0 );
1847
1848 /**
1849 * Convert a timestamp in one of the formats accepted by wfTimestamp()
1850 * to the format used for inserting into timestamp fields in this DBMS. If
1851 * NULL is input, it is passed through, allowing NULL values to be inserted
1852 * into timestamp fields.
1853 *
1854 * The result is unquoted, and needs to be passed through addQuotes()
1855 * before it can be included in raw SQL.
1856 *
1857 * @param string|int $ts
1858 *
1859 * @return string
1860 */
1861 public function timestampOrNull( $ts = null );
1862
1863 /**
1864 * Ping the server and try to reconnect if it there is no connection
1865 *
1866 * @param float|null &$rtt Value to store the estimated RTT [optional]
1867 * @return bool Success or failure
1868 */
1869 public function ping( &$rtt = null );
1870
1871 /**
1872 * Get the amount of replication lag for this database server
1873 *
1874 * Callers should avoid using this method while a transaction is active
1875 *
1876 * @return int|bool Database replication lag in seconds or false on error
1877 * @throws DBError
1878 */
1879 public function getLag();
1880
1881 /**
1882 * Get the replica DB lag when the current transaction started
1883 * or a general lag estimate if not transaction is active
1884 *
1885 * This is useful when transactions might use snapshot isolation
1886 * (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data
1887 * is this lag plus transaction duration. If they don't, it is still
1888 * safe to be pessimistic. In AUTOCOMMIT mode, this still gives an
1889 * indication of the staleness of subsequent reads.
1890 *
1891 * @return array ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
1892 * @throws DBError
1893 * @since 1.27
1894 */
1895 public function getSessionLagStatus();
1896
1897 /**
1898 * Return the maximum number of items allowed in a list, or 0 for unlimited.
1899 *
1900 * @return int
1901 */
1902 public function maxListLen();
1903
1904 /**
1905 * Some DBMSs have a special format for inserting into blob fields, they
1906 * don't allow simple quoted strings to be inserted. To insert into such
1907 * a field, pass the data through this function before passing it to
1908 * IDatabase::insert().
1909 *
1910 * @param string $b
1911 * @return string|Blob
1912 */
1913 public function encodeBlob( $b );
1914
1915 /**
1916 * Some DBMSs return a special placeholder object representing blob fields
1917 * in result objects. Pass the object through this function to return the
1918 * original string.
1919 *
1920 * @param string|Blob $b
1921 * @return string
1922 */
1923 public function decodeBlob( $b );
1924
1925 /**
1926 * Override database's default behavior. $options include:
1927 * 'connTimeout' : Set the connection timeout value in seconds.
1928 * May be useful for very long batch queries such as
1929 * full-wiki dumps, where a single query reads out over
1930 * hours or days.
1931 *
1932 * @param array $options
1933 * @return void
1934 * @throws DBError
1935 */
1936 public function setSessionOptions( array $options );
1937
1938 /**
1939 * Set variables to be used in sourceFile/sourceStream, in preference to the
1940 * ones in $GLOBALS. If an array is set here, $GLOBALS will not be used at
1941 * all. If it's set to false, $GLOBALS will be used.
1942 *
1943 * @param bool|array $vars Mapping variable name to value.
1944 */
1945 public function setSchemaVars( $vars );
1946
1947 /**
1948 * Check to see if a named lock is not locked by any thread (non-blocking)
1949 *
1950 * @param string $lockName Name of lock to poll
1951 * @param string $method Name of method calling us
1952 * @return bool
1953 * @throws DBError
1954 * @since 1.20
1955 */
1956 public function lockIsFree( $lockName, $method );
1957
1958 /**
1959 * Acquire a named lock
1960 *
1961 * Named locks are not related to transactions
1962 *
1963 * @param string $lockName Name of lock to aquire
1964 * @param string $method Name of the calling method
1965 * @param int $timeout Acquisition timeout in seconds
1966 * @return bool
1967 * @throws DBError
1968 */
1969 public function lock( $lockName, $method, $timeout = 5 );
1970
1971 /**
1972 * Release a lock
1973 *
1974 * Named locks are not related to transactions
1975 *
1976 * @param string $lockName Name of lock to release
1977 * @param string $method Name of the calling method
1978 *
1979 * @return int Returns 1 if the lock was released, 0 if the lock was not established
1980 * by this thread (in which case the lock is not released), and NULL if the named lock
1981 * did not exist
1982 *
1983 * @throws DBError
1984 */
1985 public function unlock( $lockName, $method );
1986
1987 /**
1988 * Acquire a named lock, flush any transaction, and return an RAII style unlocker object
1989 *
1990 * Only call this from outer transcation scope and when only one DB will be affected.
1991 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1992 *
1993 * This is suitiable for transactions that need to be serialized using cooperative locks,
1994 * where each transaction can see each others' changes. Any transaction is flushed to clear
1995 * out stale REPEATABLE-READ snapshot data. Once the returned object falls out of PHP scope,
1996 * the lock will be released unless a transaction is active. If one is active, then the lock
1997 * will be released when it either commits or rolls back.
1998 *
1999 * If the lock acquisition failed, then no transaction flush happens, and null is returned.
2000 *
2001 * @param string $lockKey Name of lock to release
2002 * @param string $fname Name of the calling method
2003 * @param int $timeout Acquisition timeout in seconds
2004 * @return ScopedCallback|null
2005 * @throws DBError
2006 * @since 1.27
2007 */
2008 public function getScopedLockAndFlush( $lockKey, $fname, $timeout );
2009
2010 /**
2011 * Check to see if a named lock used by lock() use blocking queues
2012 *
2013 * @return bool
2014 * @since 1.26
2015 */
2016 public function namedLocksEnqueue();
2017
2018 /**
2019 * Find out when 'infinity' is. Most DBMSes support this. This is a special
2020 * keyword for timestamps in PostgreSQL, and works with CHAR(14) as well
2021 * because "i" sorts after all numbers.
2022 *
2023 * @return string
2024 */
2025 public function getInfinity();
2026
2027 /**
2028 * Encode an expiry time into the DBMS dependent format
2029 *
2030 * @param string $expiry Timestamp for expiry, or the 'infinity' string
2031 * @return string
2032 */
2033 public function encodeExpiry( $expiry );
2034
2035 /**
2036 * Decode an expiry time into a DBMS independent format
2037 *
2038 * @param string $expiry DB timestamp field value for expiry
2039 * @param int $format TS_* constant, defaults to TS_MW
2040 * @return string
2041 */
2042 public function decodeExpiry( $expiry, $format = TS_MW );
2043
2044 /**
2045 * Allow or deny "big selects" for this session only. This is done by setting
2046 * the sql_big_selects session variable.
2047 *
2048 * This is a MySQL-specific feature.
2049 *
2050 * @param bool|string $value True for allow, false for deny, or "default" to
2051 * restore the initial value
2052 */
2053 public function setBigSelects( $value = true );
2054
2055 /**
2056 * @return bool Whether this DB is read-only
2057 * @since 1.27
2058 */
2059 public function isReadOnly();
2060
2061 /**
2062 * Make certain table names use their own database, schema, and table prefix
2063 * when passed into SQL queries pre-escaped and without a qualified database name
2064 *
2065 * For example, "user" can be converted to "myschema.mydbname.user" for convenience.
2066 * Appearances like `user`, somedb.user, somedb.someschema.user will used literally.
2067 *
2068 * Calling this twice will completely clear any old table aliases. Also, note that
2069 * callers are responsible for making sure the schemas and databases actually exist.
2070 *
2071 * @param array[] $aliases Map of (table => (dbname, schema, prefix) map)
2072 * @since 1.28
2073 */
2074 public function setTableAliases( array $aliases );
2075
2076 /**
2077 * Convert certain index names to alternative names before querying the DB
2078 *
2079 * Note that this applies to indexes regardless of the table they belong to.
2080 *
2081 * This can be employed when an index was renamed X => Y in code, but the new Y-named
2082 * indexes were not yet built on all DBs. After all the Y-named ones are added by the DBA,
2083 * the aliases can be removed, and then the old X-named indexes dropped.
2084 *
2085 * @param string[] $aliases
2086 * @return mixed
2087 * @since 1.31
2088 */
2089 public function setIndexAliases( array $aliases );
2090 }
2091
2092 class_alias( IDatabase::class, 'IDatabase' );