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wiki.techinc.nl/includes/libs/rdbms/database/IDatabase.php
Amir Sarabadani 236a0941c0 rdmbs: Start of SQLPlatform to split out of Database 
This is the first step to split parts of Database that doesn't require a
connection and are used for query parts.

Bug: T299691
Change-Id: I140aa4328865994499926f898233867ce383908c
2022-04-24 16:07:44 +00:00

2256 lines
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PHP
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<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
namespace Wikimedia\Rdbms;
use Exception;
use InvalidArgumentException;
use stdClass;
use Wikimedia\Rdbms\Platform\ISQLPlatform;
use Wikimedia\ScopedCallback;
/**
* @defgroup Database Database
* This group deals with database interface functions
* and query specifics/optimisations.
*/
/**
* Basic database interface for live and lazy-loaded relation database handles
*
* @note IDatabase and DBConnRef should be updated to reflect any changes
* @ingroup Database
*/
interface IDatabase extends ISQLPlatform {
/** @var int Callback triggered immediately due to no active transaction */
public const TRIGGER_IDLE = 1;
/** @var int Callback triggered by COMMIT */
public const TRIGGER_COMMIT = 2;
/** @var int Callback triggered by ROLLBACK */
public const TRIGGER_ROLLBACK = 3;
/** @var int Callback triggered by atomic section cancel (ROLLBACK TO SAVEPOINT) */
public const TRIGGER_CANCEL = 4;
/** @var string Transaction is requested by regular caller outside of the DB layer */
public const TRANSACTION_EXPLICIT = '';
/** @var string Transaction is requested internally via DBO_TRX/startAtomic() */
public const TRANSACTION_INTERNAL = 'implicit';
/** @var string Atomic section is not cancelable */
public const ATOMIC_NOT_CANCELABLE = '';
/** @var string Atomic section is cancelable */
public const ATOMIC_CANCELABLE = 'cancelable';
/** @var string Commit/rollback is from outside the IDatabase handle and connection manager */
public const FLUSHING_ONE = '';
/** @var string Commit/rollback is from the connection manager for the IDatabase handle */
public const FLUSHING_ALL_PEERS = 'flush';
/** @var string Commit/rollback is from the IDatabase handle internally */
public const FLUSHING_INTERNAL = 'flush-internal';
/** @var string Do not remember the prior flags */
public const REMEMBER_NOTHING = '';
/** @var string Remember the prior flags */
public const REMEMBER_PRIOR = 'remember';
/** @var string Restore to the prior flag state */
public const RESTORE_PRIOR = 'prior';
/** @var string Restore to the initial flag state */
public const RESTORE_INITIAL = 'initial';
/** @var string Estimate total time (RTT, scanning, waiting on locks, applying) */
public const ESTIMATE_TOTAL = 'total';
/** @var string Estimate time to apply (scanning, applying) */
public const ESTIMATE_DB_APPLY = 'apply';
/** @var int Combine list with comma delimiters */
public const LIST_COMMA = 0;
/** @var int Combine list with AND clauses */
public const LIST_AND = 1;
/** @var int Convert map into a SET clause */
public const LIST_SET = 2;
/** @var int Treat as field name and do not apply value escaping */
public const LIST_NAMES = 3;
/** @var int Combine list with OR clauses */
public const LIST_OR = 4;
/** @var int Enable debug logging of all SQL queries */
public const DBO_DEBUG = 1;
/** @var int Unused since 1.34 */
public const DBO_NOBUFFER = 2;
/** @var int Unused since 1.31 */
public const DBO_IGNORE = 4;
/** @var int Automatically start a transaction before running a query if none is active */
public const DBO_TRX = 8;
/** @var int Join load balancer transaction rounds (which control DBO_TRX) in non-CLI mode */
public const DBO_DEFAULT = 16;
/** @var int Use DB persistent connections if possible */
public const DBO_PERSISTENT = 32;
/** @var int DBA session mode; was used by Oracle */
public const DBO_SYSDBA = 64;
/** @var int Schema file mode; was used by Oracle */
public const DBO_DDLMODE = 128;
/** @var int Enable SSL/TLS in connection protocol */
public const DBO_SSL = 256;
/** @var int Enable compression in connection protocol */
public const DBO_COMPRESS = 512;
/** @var int Idiom for "no special flags" */
public const QUERY_NORMAL = 0;
/** @var int Ignore query errors and return false when they happen */
public const QUERY_SILENCE_ERRORS = 1; // b/c for 1.32 query() argument; (int)true = 1
/**
* @var int Treat the TEMPORARY table from the given CREATE query as if it is
* permanent as far as write tracking is concerned. This is useful for testing.
*/
public const QUERY_PSEUDO_PERMANENT = 2;
/** @var int Enforce that a query does not make effective writes */
public const QUERY_REPLICA_ROLE = 4;
/** @var int Ignore the current presence of any DBO_TRX flag */
public const QUERY_IGNORE_DBO_TRX = 8;
/** @var int Do not try to retry the query if the connection was lost */
public const QUERY_NO_RETRY = 16;
/** @var int Query is a read-only Data Query Language query */
public const QUERY_CHANGE_NONE = 32;
/** @var int Query is a Transaction Control Language command (BEGIN, USE, SET, ...) */
public const QUERY_CHANGE_TRX = 64 | self::QUERY_IGNORE_DBO_TRX;
/** @var int Query is a Data Manipulation Language command (INSERT, DELETE, LOCK, ...) */
public const QUERY_CHANGE_ROWS = 128;
/** @var int Query is a Data Definition Language command */
public const QUERY_CHANGE_SCHEMA = 256 | self::QUERY_IGNORE_DBO_TRX;
/** @var int Query is a command for advisory locks */
public const QUERY_CHANGE_LOCKS = 512 | self::QUERY_IGNORE_DBO_TRX;
/** Flag to return the lock acquisition timestamp (null if not acquired) */
public const LOCK_TIMESTAMP = 1;
/** @var bool Parameter to unionQueries() for UNION ALL */
public const UNION_ALL = true;
/** @var bool Parameter to unionQueries() for UNION DISTINCT */
public const UNION_DISTINCT = false;
/** @var string Field for getLBInfo()/setLBInfo() */
public const LB_TRX_ROUND_ID = 'trxRoundId';
/** @var string Field for getLBInfo()/setLBInfo() */
public const LB_READ_ONLY_REASON = 'readOnlyReason';
/** @var string primary DB server than can stream OLTP updates to replica servers */
public const ROLE_STREAMING_MASTER = 'streaming-master';
/** @var string Replica server that streams OLTP updates from the primary DB server */
public const ROLE_STREAMING_REPLICA = 'streaming-replica';
/** @var string Replica server of a static dataset that does not get OLTP updates */
public const ROLE_STATIC_CLONE = 'static-clone';
/** @var string Unknown replication topology role */
public const ROLE_UNKNOWN = 'unknown';
/** @var string Unconditional update/delete of whole table */
public const ALL_ROWS = '*';
/**
* Get a human-readable string describing the current software version
*
* Use getServerVersion() to get machine-friendly information.
*
* @return string Version information from the database server
*/
public function getServerInfo();
/**
* Get a non-recycled ID that uniquely identifies this server within the replication topology
*
* A replication topology defines which servers can originate changes to a given dataset
* and how those changes propagate among database servers. It is assumed that the server
* only participates in the replication of a single relevant dataset.
*
* @return string|null 32, 64, or 128 bit integer ID; null if not applicable or unknown
* @throws DBQueryError
* @since 1.37
*/
public function getTopologyBasedServerId();
/**
* Get the replication topology role of this server
*
* A replication topology defines which servers can originate changes to a given dataset
* and how those changes propagate among database servers. It is assumed that the server
* only participates in the replication of a single relevant dataset.
*
* @return string One of the class ROLE_* constants
* @throws DBQueryError
* @since 1.34
*/
public function getTopologyRole();
/**
* Get the readable name of the sole root primary DB server for the replication topology
*
* A replication topology defines which servers can originate changes to a given dataset
* and how those changes propagate among database servers. It is assumed that the server
* only participates in the replication of a single relevant dataset.
*
* @return string|null Readable server name; null if unknown or if co-primaries are defined
* @throws DBQueryError
* @since 1.37
*/
public function getTopologyRootPrimary();
/**
* Gets the current transaction level.
*
* Historically, transactions were allowed to be "nested". This is no
* longer supported, so this function really only returns a boolean.
*
* @return int The previous value
*/
public function trxLevel();
/**
* Get the UNIX timestamp of the time that the transaction was established
*
* This can be used to reason about the staleness of SELECT data in REPEATABLE-READ
* transaction isolation level. Callers can assume that if a view-snapshot isolation
* is used, then the data read by SQL queries is *at least* up to date to that point
* (possibly more up-to-date since the first SELECT defines the snapshot).
*
* @return float|null Returns null if there is not active transaction
* @since 1.25
*/
public function trxTimestamp();
/**
* Check whether there is a transaction open at the specific request of a caller
*
* Explicit transactions are spawned by begin(), startAtomic(), and doAtomicSection().
* Note that explicit transactions should not be confused with explicit transaction rounds.
*
* @return bool
* @since 1.28
*/
public function explicitTrxActive();
/**
* Get/set the table prefix
*
* @param string|null $prefix The table prefix to set, or omitted to leave it unchanged
* @return string The previous table prefix
*/
public function tablePrefix( $prefix = null );
/**
* Get/set the db schema
*
* @param string|null $schema The database schema to set, or omitted to leave it unchanged
* @return string The previous db schema
*/
public function dbSchema( $schema = null );
/**
* Get properties passed down from the server info array of the load balancer
*
* @param string|null $name The entry of the info array to get, or null to get the whole array
* @return array|mixed|null
*/
public function getLBInfo( $name = null );
/**
* Set the entire array or a particular key of the managing load balancer info array
*
* Keys matching the IDatabase::LB_* constants are also used internally by subclasses
*
* @param array|string $nameOrArray The new array or the name of a key to set
* @param array|mixed|null $value If $nameOrArray is a string, the new key value (null to unset)
*/
public function setLBInfo( $nameOrArray, $value = null );
/**
* Returns true if this database does an implicit order by when the column has an index
* For example: SELECT page_title FROM page LIMIT 1
*
* @return bool
*/
public function implicitOrderby();
/**
* Get the last query that sent on account of IDatabase::query()
*
* @return string SQL text or empty string if there was no such query
*/
public function lastQuery();
/**
* Get the last time the connection may have been used for a write query
*
* @return int|float|false UNIX timestamp or false
* @since 1.24
*/
public function lastDoneWrites();
/**
* @return bool Whether there is a transaction open with possible write queries
* @since 1.27
*/
public function writesPending();
/**
* Whether there is a transaction open with either possible write queries
* or unresolved pre-commit/commit/resolution callbacks pending
*
* This does *not* count recurring callbacks, e.g. from setTransactionListener().
*
* @return bool
*/
public function writesOrCallbacksPending();
/**
* Get the time spend running write queries for this transaction
*
* High values could be due to scanning, updates, locking, and such.
*
* @param string $type IDatabase::ESTIMATE_* constant [default: ESTIMATE_ALL]
* @return float|bool Returns false if not transaction is active
* @since 1.26
*/
public function pendingWriteQueryDuration( $type = self::ESTIMATE_TOTAL );
/**
* Get the list of method names that did write queries for this transaction
*
* @return array
* @since 1.27
*/
public function pendingWriteCallers();
/**
* @return bool Whether a connection to the database open
*/
public function isOpen();
/**
* Set a flag for this connection
*
* @param int $flag One of (IDatabase::DBO_DEBUG, IDatabase::DBO_TRX)
* @param string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]
*/
public function setFlag( $flag, $remember = self::REMEMBER_NOTHING );
/**
* Clear a flag for this connection
*
* @param int $flag One of (IDatabase::DBO_DEBUG, IDatabase::DBO_TRX)
* @param string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]
*/
public function clearFlag( $flag, $remember = self::REMEMBER_NOTHING );
/**
* Restore the flags to their prior state before the last setFlag/clearFlag call
*
* @param string $state IDatabase::RESTORE_* constant. [default: RESTORE_PRIOR]
* @since 1.28
*/
public function restoreFlags( $state = self::RESTORE_PRIOR );
/**
* Returns a boolean whether the flag $flag is set for this connection
*
* @param int $flag One of the class IDatabase::DBO_* constants
* @return bool
*/
public function getFlag( $flag );
/**
* Return the currently selected domain ID
*
* Null components (database/schema) might change once a connection is established
*
* @return string
*/
public function getDomainID();
/**
* Get the RDBMS type of the server (e.g. "mysql", "sqlite")
*
* @return string
*/
public function getType();
/**
* Get the inserted value of an auto-increment row
*
* This should only be called after an insert that used an auto-incremented
* value. If no such insert was previously done in the current database
* session, the return value is undefined.
*
* @return int
*/
public function insertId();
/**
* Get the last error number
* @see https://www.php.net/mysql_errno
*
* @return int
*/
public function lastErrno();
/**
* Get a description of the last error
* @see https://www.php.net/mysql_error
*
* @return string
*/
public function lastError();
/**
* Get the number of rows affected by the last write query.
* Similar to https://www.php.net/mysql_affected_rows but includes rows matched
* but not changed (ie. an UPDATE which sets all fields to the same value they already have).
* To get the old mysql_affected_rows behavior, include non-equality of the fields in WHERE.
*
* @return int
*/
public function affectedRows();
/**
* Returns a wikitext style link to the DB's website (e.g. "[https://www.mysql.com/ MySQL]")
*
* Should at least contain plain text, if for some reason your database has no website.
*
* @return string Wikitext of a link to the server software's web site
*/
public function getSoftwareLink();
/**
* A string describing the current software version, like from mysql_get_server_info()
*
* @return string Version information from the database server.
*/
public function getServerVersion();
/**
* Close the database connection
*
* This should only be called after any transactions have been resolved,
* aside from read-only automatic transactions (assuming no callbacks are registered).
* If a transaction is still open anyway, it will be rolled back.
*
* @param string $fname Caller name
* @param int|null $owner ID of the calling instance (e.g. the LBFactory ID)
* @return bool Success
* @throws DBError
*/
public function close( $fname = __METHOD__, $owner = null );
/**
* Run an SQL query and return the result
*
* If a connection loss is detected, then an attempt to reconnect will be made.
* For queries that involve no larger transactions or locks, they will be re-issued
* for convenience, provided the connection was re-established.
*
* In new code, the query wrappers select(), insert(), update(), delete(),
* etc. should be used where possible, since they give much better DBMS
* independence and automatically quote or validate user input in a variety
* of contexts. This function is generally only useful for queries which are
* explicitly DBMS-dependent and are unsupported by the query wrappers, such
* as CREATE TABLE.
*
* However, the query wrappers themselves should call this function.
*
* @param string $sql SQL query
* @param string $fname Name of the calling function, for profiling/SHOW PROCESSLIST
* comment (you can use __METHOD__ or add some extra info)
* @param int $flags Bit field of IDatabase::QUERY_* constants. Note that suppression
* of errors is best handled by try/catch rather than using one of these flags.
* @return bool|IResultWrapper True for a successful write query, IResultWrapper object
* for a successful read query, or false on failure if QUERY_SILENCE_ERRORS is set.
* @throws DBQueryError If the query is issued, fails, and QUERY_SILENCE_ERRORS is not set.
* @throws DBExpectedError If the query is not, and cannot, be issued yet (non-DBQueryError)
* @throws DBError If the query is inherently not allowed (non-DBExpectedError)
*/
public function query( $sql, $fname = __METHOD__, $flags = 0 );
/**
* Create an empty SelectQueryBuilder which can be used to run queries
* against this connection.
*
* @return SelectQueryBuilder
*/
public function newSelectQueryBuilder(): SelectQueryBuilder;
/**
* A SELECT wrapper which returns a single field from a single result row
*
* If no result rows are returned from the query, false is returned.
*
* @param string|array $table Table name. {@see select} for details.
* @param string|array $var The field name to select. This must be a valid SQL fragment: do not
* use unvalidated user input. Can be an array, but must contain exactly 1 element then.
* {@see select} for details.
* @param string|array $cond The condition array. {@see select} for details.
* @param string $fname The function name of the caller.
* @param string|array $options The query options. {@see select} for details.
* @param string|array $join_conds The query join conditions. {@see select} for details.
* @return mixed|false The value from the field, or false if nothing was found
* @throws DBError If an error occurs, {@see query}
*/
public function selectField(
$table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
);
/**
* A SELECT wrapper which returns a list of single field values from result rows
*
* If no result rows are returned from the query, an empty array is returned.
*
* @param string|array $table Table name. {@see select} for details.
* @param string $var The field name to select. This must be a valid SQL
* fragment: do not use unvalidated user input.
* @param string|array $cond The condition array. {@see select} for details.
* @param string $fname The function name of the caller.
* @param string|array $options The query options. {@see select} for details.
* @param string|array $join_conds The query join conditions. {@see select} for details.
*
* @return array The values from the field in the order they were returned from the DB
* @throws DBError If an error occurs, {@see query}
* @since 1.25
*/
public function selectFieldValues(
$table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
): array;
/**
* Execute a SELECT query constructed using the various parameters provided
*
* @param string|array $table Table name(s)
*
* May be either an array of table names, or a single string holding a table
* name. If an array is given, table aliases can be specified, for example:
*
* [ 'a' => 'user' ]
*
* This includes the user table in the query, with the alias "a" available
* for use in field names (e.g. a.user_name).
*
* A derived table, defined by the result of selectSQLText(), requires an alias
* key and a Subquery instance value which wraps the SQL query, for example:
*
* [ 'c' => new Subquery( 'SELECT ...' ) ]
*
* Joins using parentheses for grouping (since MediaWiki 1.31) may be
* constructed using nested arrays. For example,
*
* [ 'tableA', 'nestedB' => [ 'tableB', 'b2' => 'tableB2' ] ]
*
* along with `$join_conds` like
*
* [ 'b2' => [ 'JOIN', 'b_id = b2_id' ], 'nestedB' => [ 'LEFT JOIN', 'b_a = a_id' ] ]
*
* will produce SQL something like
*
* FROM tableA LEFT JOIN (tableB JOIN tableB2 AS b2 ON (b_id = b2_id)) ON (b_a = a_id)
*
* All of the table names given here are automatically run through
* Database::tableName(), which causes the table prefix (if any) to be
* added, and various other table name mappings to be performed.
*
* Do not use untrusted user input as a table name. Alias names should
* not have characters outside of the Basic multilingual plane.
*
* @param string|array $vars Field name(s)
*
* May be either a field name or an array of field names. The field names
* can be complete fragments of SQL, for direct inclusion into the SELECT
* query. If an array is given, field aliases can be specified, for example:
*
* [ 'maxrev' => 'MAX(rev_id)' ]
*
* This includes an expression with the alias "maxrev" in the query.
*
* If an expression is given, care must be taken to ensure that it is
* DBMS-independent.
*
* Untrusted user input must not be passed to this parameter.
*
* @param string|array $conds
*
* May be either a string containing a single condition, or an array of
* conditions. If an array is given, the conditions constructed from each
* element are combined with AND.
*
* Array elements may take one of two forms:
*
* - Elements with a numeric key are interpreted as raw SQL fragments.
* - Elements with a string key are interpreted as equality conditions,
* where the key is the field name.
* - If the value of such an array element is a scalar (such as a
* string), it will be treated as data and thus quoted appropriately.
* If it is null, an IS NULL clause will be added.
* - If the value is an array, an IN (...) clause will be constructed
* from its non-null elements, and an IS NULL clause will be added
* if null is present, such that the field may match any of the
* elements in the array. The non-null elements will be quoted.
*
* Note that expressions are often DBMS-dependent in their syntax.
* DBMS-independent wrappers are provided for constructing several types of
* expression commonly used in condition queries. See:
* - IDatabase::buildLike()
* - IDatabase::conditional()
*
* Untrusted user input is safe in the values of string keys, however untrusted
* input must not be used in the array key names or in the values of numeric keys.
* Escaping of untrusted input used in values of numeric keys should be done via
* IDatabase::addQuotes()
*
* Use an empty array, string, or IDatabase::ALL_ROWS to select all rows.
*
* You *can* put simple join conditions here, but this is strongly discouraged.
* Instead of
*
* // $conds...
* 'rev_actor = actor_id',
*
* use (see below for $join_conds):
*
* // $join_conds...
* 'actor' => [ 'JOIN', 'rev_actor = actor_id' ],
*
* @param string $fname Caller function name
*
* @param string|array $options Query options
*
* Optional: Array of query options. Boolean options are specified by
* including them in the array as a string value with a numeric key, for
* example:
*
* [ 'FOR UPDATE' ]
*
* The supported options are:
*
* - OFFSET: Skip this many rows at the start of the result set. OFFSET
* with LIMIT can theoretically be used for paging through a result set,
* but this is discouraged for performance reasons.
*
* - LIMIT: Integer: return at most this many rows. The rows are sorted
* and then the first rows are taken until the limit is reached. LIMIT
* is applied to a result set after OFFSET.
*
* - LOCK IN SHARE MODE: Boolean: lock the returned rows so that they can't be
* changed until the next COMMIT. Cannot be used with aggregate functions
* (COUNT, MAX, etc., but also DISTINCT).
*
* - FOR UPDATE: Boolean: lock the returned rows so that they can't be
* changed nor read with LOCK IN SHARE MODE until the next COMMIT.
* Cannot be used with aggregate functions (COUNT, MAX, etc., but also DISTINCT).
*
* - DISTINCT: Boolean: return only unique result rows.
*
* - GROUP BY: May be either an SQL fragment string naming a field or
* expression to group by, or an array of such SQL fragments.
*
* - HAVING: May be either an string containing a HAVING clause or an array of
* conditions building the HAVING clause. If an array is given, the conditions
* constructed from each element are combined with AND.
*
* - ORDER BY: May be either an SQL fragment giving a field name or
* expression to order by, or an array of such SQL fragments.
*
* - USE INDEX: This may be either a string giving the index name to use
* for the query, or an array. If it is an associative array, each key
* gives the table name (or alias), each value gives the index name to
* use for that table. All strings are SQL fragments and so should be
* validated by the caller.
*
* - IGNORE INDEX: This may be either be a string giving an index name to
* ignore for the query, or an array. If it is an associative array,
* each key gives the table name (or alias), each value gives the index
* name to ignore for that table. All strings are SQL fragments and so
* should be validated by the caller.
*
* - EXPLAIN: In MySQL, this causes an EXPLAIN SELECT query to be run,
* instead of SELECT.
*
* - MAX_EXECUTION_TIME: (only in MySQL/MariaDB) maximum allowed time to
* run the query in milliseconds (if database supports it).
*
* And also the following boolean MySQL extensions, see the MySQL manual
* for documentation:
*
* - STRAIGHT_JOIN
* - SQL_BIG_RESULT
* - SQL_BUFFER_RESULT
* - SQL_SMALL_RESULT
* - SQL_CALC_FOUND_ROWS
*
* @param string|array $join_conds Join conditions
*
* Optional associative array of table-specific join conditions.
* Simple conditions can also be specified in the regular $conds,
* but this is strongly discouraged in favor of the more explicit syntax here.
*
* The key of the array contains the table name or alias. The value is an
* array with two elements, numbered 0 and 1. The first gives the type of
* join, the second is the same as the $conds parameter. Thus it can be
* an SQL fragment, or an array where the string keys are equality and the
* numeric keys are SQL fragments all AND'd together. For example:
*
* [ 'page' => [ 'LEFT JOIN', 'page_latest=rev_id' ] ]
*
* @return IResultWrapper Resulting rows
* @throws DBError If an error occurs, {@see query}
*/
public function select(
$table,
$vars,
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = []
);
/**
* Take the same arguments as IDatabase::select() and return the SQL it would use
*
* This can be useful for making UNION queries, where the SQL text of each query
* is needed. In general, however, callers outside of Database classes should just
* use select().
*
* @see IDatabase::select()
*
* @param string|array $table Table name
* @param string|array $vars Field names
* @param string|array $conds Conditions
* @param string $fname Caller function name
* @param string|array $options Query options
* @param string|array $join_conds Join conditions
* @return string SQL query string
*/
public function selectSQLText(
$table,
$vars,
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = []
);
/**
* Wrapper to IDatabase::select() that only fetches one row (via LIMIT)
*
* If the query returns no rows, false is returned.
*
* This method is convenient for fetching a row based on a unique key condition.
*
* @param string|array $table Table name
* @param string|array $vars Field names
* @param string|array $conds Conditions
* @param string $fname Caller function name
* @param string|array $options Query options
* @param array|string $join_conds Join conditions
* @return stdClass|bool
* @throws DBError If an error occurs, {@see query}
*/
public function selectRow(
$table,
$vars,
$conds,
$fname = __METHOD__,
$options = [],
$join_conds = []
);
/**
* Estimate the number of rows in dataset
*
* MySQL allows you to estimate the number of rows that would be returned
* by a SELECT query, using EXPLAIN SELECT. The estimate is provided using
* index cardinality statistics, and is notoriously inaccurate, especially
* when large numbers of rows have recently been added or deleted.
*
* For DBMSs that don't support fast result size estimation, this function
* will actually perform the SELECT COUNT(*).
*
* Takes the same arguments as IDatabase::select().
*
* @param string|string[] $tables Table name(s)
* @param string $var Column for which NULL values are not counted [default "*"]
* @param array|string $conds Filters on the table
* @param string $fname Function name for profiling
* @param array $options Options for select
* @param array|string $join_conds Join conditions
* @return int Row count
* @throws DBError If an error occurs, {@see query}
*/
public function estimateRowCount(
$tables, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
);
/**
* Get the number of rows in dataset
*
* This is useful when trying to do COUNT(*) but with a LIMIT for performance.
*
* Takes the same arguments as IDatabase::select().
*
* @since 1.27 Added $join_conds parameter
*
* @param string|string[] $tables Table name(s)
* @param string $var Column for which NULL values are not counted [default "*"]
* @param array|string $conds Filters on the table
* @param string $fname Function name for profiling
* @param array $options Options for select
* @param array $join_conds Join conditions (since 1.27)
* @return int Row count
* @throws DBError If an error occurs, {@see query}
*/
public function selectRowCount(
$tables, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
);
/**
* Lock all rows meeting the given conditions/options FOR UPDATE
*
* @param string|string[] $table Table name(s)
* @param array|string $conds Filters on the table
* @param string $fname Function name for profiling
* @param array $options Options for select ("FOR UPDATE" is added automatically)
* @param array $join_conds Join conditions
* @return int Number of matching rows found (and locked)
* @throws DBError If an error occurs, {@see query}
* @since 1.32
*/
public function lockForUpdate(
$table, $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
);
/**
* Determines whether a field exists in a table
*
* @param string $table Table name
* @param string $field Field to check on that table
* @param string $fname Calling function name (optional)
* @return bool Whether $table has field $field
* @throws DBError If an error occurs, {@see query}
*/
public function fieldExists( $table, $field, $fname = __METHOD__ );
/**
* Determines whether an index exists
*
* @param string $table
* @param string $index
* @param string $fname
* @return bool|null
* @throws DBError If an error occurs, {@see query}
*/
public function indexExists( $table, $index, $fname = __METHOD__ );
/**
* Query whether a given table exists
*
* @param string $table
* @param string $fname
* @return bool
* @throws DBError If an error occurs, {@see query}
*/
public function tableExists( $table, $fname = __METHOD__ );
/**
* Insert the given row(s) into a table
*
* @param string $table Table name
* @param array|array[] $rows Row(s) to insert, as either:
* - A string-keyed map of (column name => value) defining a new row. Values are
* treated as literals and quoted appropriately; null is interpreted as NULL.
* - An integer-keyed list of such string-keyed maps, defining a list of new rows.
* The keys in each map must be identical to each other and in the same order.
* The rows must not collide with each other.
* @param string $fname Calling function name (use __METHOD__) for logs/profiling
* @param string|array $options Combination map/list where each string-keyed entry maps
* a non-boolean option to the option parameters and each integer-keyed value is the
* name of a boolean option. Supported options are:
* - IGNORE: Boolean: skip insertion of rows that would cause unique key conflicts.
* IDatabase::affectedRows() can be used to determine how many rows were inserted.
* @return bool Return true if no exception was thrown (deprecated since 1.33)
* @throws DBError If an error occurs, {@see query}
*/
public function insert( $table, $rows, $fname = __METHOD__, $options = [] );
/**
* Update all rows in a table that match a given condition
*
* @param string $table Table name
* @param array $set Combination map/list where each string-keyed entry maps a column
* to a literal assigned value and each integer-keyed value is a SQL expression in the
* format of a column assignment within UPDATE...SET. The (column => value) entries are
* convenient due to automatic value quoting and conversion of null to NULL. The SQL
* assignment format is useful for updates like "column = column + X". All assignments
* have no defined execution order, so they should not depend on each other. Do not
* modify AUTOINCREMENT or UUID columns in assignments.
* @param array|string $conds Condition in the format of IDatabase::select() conditions.
* In order to prevent possible performance or replication issues or damaging a data
* accidentally, an empty condition for 'update' queries isn't allowed.
* IDatabase::ALL_ROWS should be passed explicitely in order to update all rows.
* @param string $fname Calling function name (use __METHOD__) for logs/profiling
* @param string|array $options Combination map/list where each string-keyed entry maps
* a non-boolean option to the option parameters and each integer-keyed value is the
* name of a boolean option. Supported options are:
* - IGNORE: Boolean: skip update of rows that would cause unique key conflicts.
* IDatabase::affectedRows() can be used to determine how many rows were updated.
* @return bool Return true if no exception was thrown (deprecated since 1.33)
* @throws DBError If an error occurs, {@see query}
*/
public function update( $table, $set, $conds, $fname = __METHOD__, $options = [] );
/**
* Makes an encoded list of strings from an array
*
* These can be used to make conjunctions or disjunctions on SQL condition strings
* derived from an array ({@see select} $conds documentation).
*
* Example usage:
* @code
* $sql = $db->makeList( [
* 'rev_page' => $id,
* $db->makeList( [ 'rev_minor' => 1, 'rev_len < 500' ], $db::LIST_OR )
* ], $db::LIST_AND );
* @endcode
* This would set $sql to "rev_page = '$id' AND (rev_minor = 1 OR rev_len < 500)"
*
* @param array $a Containing the data
* @param int $mode IDatabase class constant:
* - IDatabase::LIST_COMMA: Comma separated, no field names
* - IDatabase::LIST_AND: ANDed WHERE clause (without the WHERE).
* - IDatabase::LIST_OR: ORed WHERE clause (without the WHERE)
* - IDatabase::LIST_SET: Comma separated with field names, like a SET clause
* - IDatabase::LIST_NAMES: Comma separated field names
* @throws DBError If an error occurs, {@see query}
* @return string
*/
public function makeList( array $a, $mode = self::LIST_COMMA );
/**
* Build a partial where clause from a 2-d array such as used for LinkBatch.
*
* The keys on each level may be either integers or strings, however it's
* assumed that $baseKey is probably an integer-typed column (i.e. integer
* keys are unquoted in the SQL) and $subKey is string-typed (i.e. integer
* keys are quoted as strings in the SQL).
*
* @todo Does this actually belong in the library? It seems overly MW-specific.
*
* @param array $data Organized as 2-d
* [ baseKeyVal => [ subKeyVal => [ignored], ... ], ... ]
* @param string $baseKey Field name to match the base-level keys to (eg 'pl_namespace')
* @param string $subKey Field name to match the sub-level keys to (eg 'pl_title')
* @return string|bool SQL fragment, or false if no items in array
*/
public function makeWhereFrom2d( $data, $baseKey, $subKey );
/**
* Given an array of condition arrays representing an OR list of AND lists,
* for example:
*
* (A=1 AND B=2) OR (A=1 AND B=3)
*
* produce an SQL expression in which the conditions are factored:
*
* (A=1 AND (B=2 OR B=3))
*
* We also use IN() to simplify further:
*
* (A=1 AND (B IN (2,3))
*
* More compactly, in boolean algebra notation, a sum of products, e.g.
* AB + AC is factored to produce A(B+C). Factoring proceeds recursively
* to reduce expressions with any number of variables, for example
* AEP + AEQ + AFP + AFQ = A(E(P+Q) + F(P+Q))
*
* The algorithm is simple and will not necessarily find the shortest
* possible expression. For the best results, fields should be given in a
* consistent order, and the fields with values likely to be shared should
* be leftmost in the associative arrays.
*
* @param array $condsArray An array of associative arrays. The associative
* array keys represent field names, and the values represent the field
* values to compare against.
* @return string SQL expression fragment
*/
public function factorConds( $condsArray );
/**
* Build a concatenation list to feed into a SQL query
* @param string[] $stringList Raw SQL expression list; caller is responsible for escaping
* @return string
*/
public function buildConcat( $stringList );
/**
* Build a GROUP_CONCAT or equivalent statement for a query.
*
* This is useful for combining a field for several rows into a single string.
* NULL values will not appear in the output, duplicated values will appear,
* and the resulting delimiter-separated values have no defined sort order.
* Code using the results may need to use the PHP unique() or sort() methods.
*
* @param string $delim Glue to bind the results together
* @param string|array $table Table name
* @param string $field Field name
* @param string|array $conds Conditions
* @param string|array $join_conds Join conditions
* @return string SQL text
* @since 1.23
*/
public function buildGroupConcatField(
$delim, $table, $field, $conds = '', $join_conds = []
);
/**
* Build a GREATEST function statement comparing columns/values
*
* Integer and float values in $values will not be quoted
*
* If $fields is an array, then each value with a string key is treated as an expression
* (which must be manually quoted); such string keys do not appear in the SQL and are only
* descriptive aliases.
*
* @param string|string[] $fields Name(s) of column(s) with values to compare
* @param string|int|float|string[]|int[]|float[] $values Values to compare
* @return mixed
* @since 1.35
*/
public function buildGreatest( $fields, $values );
/**
* Build a LEAST function statement comparing columns/values
*
* Integer and float values in $values will not be quoted
*
* If $fields is an array, then each value with a string key is treated as an expression
* (which must be manually quoted); such string keys do not appear in the SQL and are only
* descriptive aliases.
*
* @param string|string[] $fields Name(s) of column(s) with values to compare
* @param string|int|float|string[]|int[]|float[] $values Values to compare
* @return mixed
* @since 1.35
*/
public function buildLeast( $fields, $values );
/**
* Build a SUBSTRING function
*
* Behavior for non-ASCII values is undefined.
*
* @param string $input Field name
* @param int $startPosition Positive integer
* @param int|null $length Non-negative integer length or null for no limit
* @throws InvalidArgumentException
* @return string SQL text
* @since 1.31
*/
public function buildSubString( $input, $startPosition, $length = null );
/**
* @param string $field Field or column to cast
* @return string
* @since 1.28
*/
public function buildStringCast( $field );
/**
* @param string $field Field or column to cast
* @return string
* @since 1.31
*/
public function buildIntegerCast( $field );
/**
* Equivalent to IDatabase::selectSQLText() except wraps the result in Subquery
*
* @see IDatabase::selectSQLText()
*
* @param string|array $table Table name
* @param string|array $vars Field names
* @param string|array $conds Conditions
* @param string $fname Caller function name
* @param string|array $options Query options
* @param string|array $join_conds Join conditions
* @return Subquery
* @since 1.31
*/
public function buildSelectSubquery(
$table,
$vars,
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = []
);
/**
* Construct a LIMIT query with optional offset
*
* The SQL should be adjusted so that only the first $limit rows
* are returned. If $offset is provided as well, then the first $offset
* rows should be discarded, and the next $limit rows should be returned.
* If the result of the query is not ordered, then the rows to be returned
* are theoretically arbitrary.
*
* $sql is expected to be a SELECT, if that makes a difference.
*
* @param string $sql SQL query we will append the limit too
* @param int $limit The SQL limit
* @param int|bool $offset The SQL offset (default false)
* @return string
* @since 1.34
*/
public function limitResult( $sql, $limit, $offset = false );
/**
* Returns true if DBs are assumed to be on potentially different servers
*
* In systems like mysql/mariadb, different databases can easily be referenced on a single
* connection merely by name, even in a single query via JOIN. On the other hand, Postgres
* treats databases as logically separate, with different database users, requiring special
* mechanisms like postgres_fdw to "mount" foreign DBs. This is true even among DBs on the
* same server. Changing the selected database via selectDomain() requires a new connection.
*
* @return bool
* @since 1.29
*/
public function databasesAreIndependent();
/**
* Change the current database
*
* This should only be called by a load balancer or if the handle is not attached to one
*
* @param string $db
* @return bool True unless an exception was thrown
* @throws DBConnectionError If databasesAreIndependent() is true and connection change fails
* @throws DBError On query error or if database changes are disallowed
* @deprecated Since 1.32 Use selectDomain() instead
*/
public function selectDB( $db );
/**
* Set the current domain (database, schema, and table prefix)
*
* This will throw an error for some database types if the database is unspecified
*
* This should only be called by a load balancer or if the handle is not attached to one
*
* @param string|DatabaseDomain $domain
* @throws DBConnectionError If databasesAreIndependent() is true and connection change fails
* @throws DBError On query error, if domain changes are disallowed, or the domain is invalid
* @since 1.32
*/
public function selectDomain( $domain );
/**
* Get the current database name; null if there isn't one
*
* @return string|null
*/
public function getDBname();
/**
* Get the hostname or IP address of the server
*
* @return string|null
*/
public function getServer();
/**
* Get the readable name for the server
*
* @return string Readable server name, falling back to the hostname or IP address
* @since 1.36
*/
public function getServerName();
/**
* Escape and quote a raw value string for use in a SQL query
*
* @param string|int|float|null|bool|Blob $s
* @return string
*/
public function addQuotes( $s );
/**
* LIKE statement wrapper
*
* This takes a variable-length argument list with parts of pattern to match
* containing either string literals that will be escaped or tokens returned by
* anyChar() or anyString(). Alternatively, the function could be provided with
* an array of aforementioned parameters.
*
* Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns
* a LIKE clause that searches for subpages of 'My page title'.
* Alternatively:
* $pattern = [ 'My_page_title/', $dbr->anyString() ];
* $query .= $dbr->buildLike( $pattern );
*
* @since 1.16
* @param array[]|string|LikeMatch $param
* @param string|LikeMatch ...$params
* @return string Fully built LIKE statement
*/
public function buildLike( $param, ...$params );
/**
* Returns a token for buildLike() that denotes a '_' to be used in a LIKE query
*
* @return LikeMatch
*/
public function anyChar();
/**
* Returns a token for buildLike() that denotes a '%' to be used in a LIKE query
*
* @return LikeMatch
*/
public function anyString();
/**
* Deprecated method, calls should be removed
*
* This was formerly used for PostgreSQL to handle
* self::insertId() auto-incrementing fields. It is no longer necessary
* since DatabasePostgres::insertId() has been reimplemented using
* `lastval()`
*
* Implementations should return null if inserting `NULL` into an
* auto-incrementing field works, otherwise it should return an instance of
* NextSequenceValue and filter it on calls to relevant methods.
*
* @deprecated since 1.30, no longer needed
* @param string $seqName
* @return null|NextSequenceValue
*/
public function nextSequenceValue( $seqName );
/**
* Insert row(s) into a table, deleting all conflicting rows beforehand
*
* Note some important implications of the deletion semantics:
* - If the table has an AUTOINCREMENT column and $rows omit that column, then any
* conflicting existing rows will be replaced with newer having higher values for
* that column, even if nothing else changed.
* - There might be worse contention than upsert() due to the use of gap-locking.
* This does not apply to RDBMS types that use predicate locking nor those that
* just lock the whole table or databases anyway.
*
* @param string $table The table name
* @param string|string[]|string[][] $uniqueKeys Column name or non-empty list of column
* name lists that define all applicable unique keys on the table. There must only be
* one such key. Each unique key on the table is "applicable" unless either:
* - It involves an AUTOINCREMENT column for which no values are assigned in $rows
* - It involves a UUID column for which newly generated UUIDs are assigned in $rows
* @param array|array[] $rows Row(s) to insert, in the form of either:
* - A string-keyed map of (column name => value) defining a new row. Values are
* treated as literals and quoted appropriately; null is interpreted as NULL.
* Columns belonging to a key in $uniqueKeys must be defined here and non-null.
* - An integer-keyed list of such string-keyed maps, defining a list of new rows.
* The keys in each map must be identical to each other and in the same order.
* The rows must not collide with each other.
* @param string $fname Calling function name (use __METHOD__) for logs/profiling
* @throws DBError If an error occurs, {@see query}
*/
public function replace( $table, $uniqueKeys, $rows, $fname = __METHOD__ );
/**
* Upsert the given row(s) into a table
*
* This updates any existing rows that conflict with the provided rows and inserts
* any of the provided rows that do not conflict with existing rows. Conflicts are
* determined by the provided unique indexes.
*
* @param string $table Table name
* @param array|array[] $rows Row(s) to insert, in the form of either:
* - A string-keyed map of (column name => value) defining a new row. Values are
* treated as literals and quoted appropriately; null is interpreted as NULL.
* Columns belonging to a key in $uniqueKeys must be defined here and non-null.
* - An integer-keyed list of such string-keyed maps, defining a list of new rows.
* The keys in each map must be identical to each other and in the same order.
* The rows must not collide with each other.
* @param string|string[]|string[][] $uniqueKeys Column name or non-empty list of column
* name lists that define all applicable unique keys on the table. There must only be
* one such key. Each unique key on the table is "applicable" unless either:
* - It involves an AUTOINCREMENT column for which no values are assigned in $rows
* - It involves a UUID column for which newly generated UUIDs are assigned in $rows
* Passing string[] to $uniqueKeys is deprecated.
* @param array $set Combination map/list where each string-keyed entry maps a column
* to a literal assigned value and each integer-keyed value is a SQL assignment expression
* of the form "<unquoted alphanumeric column> = <SQL expression>". The (column => value)
* entries are convenient due to automatic value quoting and conversion of null to NULL.
* The SQL assignment entries are useful for updates like "column = column + X". All of
* the assignments have no defined execution order, so callers should make sure that they
* not depend on each other. Do not modify AUTOINCREMENT or UUID columns in assignments,
* even if they are just "secondary" unique keys.
* @param string $fname Calling function name (use __METHOD__) for logs/profiling
* @return bool Return true if no exception was thrown (deprecated since 1.33)
* @throws DBError If an error occurs, {@see query}
* @since 1.22
*/
public function upsert(
$table, array $rows, $uniqueKeys, array $set, $fname = __METHOD__
);
/**
* DELETE where the condition is a join.
*
* MySQL overrides this to use a multi-table DELETE syntax, in other databases
* we use sub-selects
*
* For safety, an empty $conds will not delete everything. If you want to
* delete all rows where the join condition matches, set $conds=IDatabase::ALL_ROWS.
*
* DO NOT put the join condition in $conds.
*
* @param string $delTable The table to delete from.
* @param string $joinTable The other table.
* @param string $delVar The variable to join on, in the first table.
* @param string $joinVar The variable to join on, in the second table.
* @param array|string $conds Condition array of field names mapped to variables,
* ANDed together in the WHERE clause
* @param string $fname Calling function name (use __METHOD__) for logs/profiling
* @throws DBError If an error occurs, {@see query}
*/
public function deleteJoin(
$delTable,
$joinTable,
$delVar,
$joinVar,
$conds,
$fname = __METHOD__
);
/**
* Delete all rows in a table that match a condition
*
* @param string $table Table name
* @param string|array $conds Array of conditions. See $conds in IDatabase::select()
* In order to prevent possible performance or replication issues or damaging a data
* accidentally, an empty condition for 'delete' queries isn't allowed.
* IDatabase::ALL_ROWS should be passed explicitly in order to delete all rows.
* @param string $fname Name of the calling function
* @return bool Return true if no exception was thrown (deprecated since 1.33)
* @throws DBError If an error occurs, {@see query}
*/
public function delete( $table, $conds, $fname = __METHOD__ );
/**
* INSERT SELECT wrapper
*
* @warning If the insert will use an auto-increment or sequence to
* determine the value of a column, this may break replication on
* databases using statement-based replication if the SELECT is not
* deterministically ordered.
*
* @param string $destTable The table name to insert into
* @param string|array $srcTable May be either a table name, or an array of table names
* to include in a join.
* @param array $varMap Must be an associative array of the form
* [ 'dest1' => 'source1', ... ]. Source items may be literals
* rather than field names, but strings should be quoted with
* IDatabase::addQuotes()
* @param array $conds Condition array. See $conds in IDatabase::select() for
* the details of the format of condition arrays. May be "*" to copy the
* whole table.
* @param string $fname The function name of the caller, from __METHOD__
* @param array $insertOptions Options for the INSERT part of the query, see
* IDatabase::insert() for details. Also, one additional option is
* available: pass 'NO_AUTO_COLUMNS' to hint that the query does not use
* an auto-increment or sequence to determine any column values.
* @param array $selectOptions Options for the SELECT part of the query, see
* IDatabase::select() for details.
* @param array $selectJoinConds Join conditions for the SELECT part of the query, see
* IDatabase::select() for details.
* @return bool Return true if no exception was thrown (deprecated since 1.33)
* @throws DBError If an error occurs, {@see query}
*/
public function insertSelect(
$destTable,
$srcTable,
$varMap,
$conds,
$fname = __METHOD__,
$insertOptions = [],
$selectOptions = [],
$selectJoinConds = []
);
/**
* Determine if the RDBMS supports ORDER BY and LIMIT for separate subqueries within UNION
*
* @return bool
*/
public function unionSupportsOrderAndLimit();
/**
* Construct a UNION query
*
* This is used for providing overload point for other DB abstractions
* not compatible with the MySQL syntax.
* @param array $sqls SQL statements to combine
* @param bool $all Either IDatabase::UNION_ALL or IDatabase::UNION_DISTINCT
* @return string SQL fragment
*/
public function unionQueries( $sqls, $all );
/**
* Construct a UNION query for permutations of conditions
*
* Databases sometimes have trouble with queries that have multiple values
* for multiple condition parameters combined with limits and ordering.
* This method constructs queries for the Cartesian product of the
* conditions and unions them all together.
*
* @see IDatabase::select()
* @param string|array $table Table name
* @param string|array $vars Field names
* @param array $permute_conds Conditions for the Cartesian product. Keys
* are field names, values are arrays of the possible values for that
* field.
* @param string|array $extra_conds Additional conditions to include in the
* query.
* @param string $fname Caller function name
* @param string|array $options Query options. In addition to the options
* recognized by IDatabase::select(), the following may be used:
* - NOTALL: Set to use UNION instead of UNION ALL.
* - INNER ORDER BY: If specified and supported, subqueries will use this
* instead of ORDER BY.
* @param string|array $join_conds Join conditions
* @return string SQL query string.
* @since 1.30
*/
public function unionConditionPermutations(
$table,
$vars,
array $permute_conds,
$extra_conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = []
);
/**
* Returns an SQL expression for a simple conditional
*
* This doesn't need to be overridden unless CASE isn't supported in the RDBMS.
*
* @param string|array $cond SQL condition expression (yields a boolean)
* @param string $caseTrueExpression SQL expression to return when the condition is true
* @param string $caseFalseExpression SQL expression to return when the condition is false
* @return string SQL fragment
*/
public function conditional( $cond, $caseTrueExpression, $caseFalseExpression );
/**
* Returns a SQL expression for simple string replacement (e.g. REPLACE() in mysql)
*
* @param string $orig Column to modify
* @param string $old Column to seek
* @param string $new Column to replace with
* @return string
*/
public function strreplace( $orig, $old, $new );
/**
* Determines if the last failure was due to a deadlock
*
* Note that during a deadlock, the prior transaction will have been lost
*
* @return bool
*/
public function wasDeadlock();
/**
* Determines if the last failure was due to a lock timeout
*
* Note that during a lock wait timeout, the prior transaction will have been lost
*
* @return bool
*/
public function wasLockTimeout();
/**
* Determines if the last query error was due to a dropped connection
*
* Note that during a connection loss, the prior transaction will have been lost
*
* @return bool
* @since 1.31
*/
public function wasConnectionLoss();
/**
* Determines if the last failure was due to the database being read-only
*
* @return bool
*/
public function wasReadOnlyError();
/**
* Determines if the last query error was due to something outside of the query itself
*
* Note that the transaction may have been lost, discarding prior writes and results
*
* @return bool
*/
public function wasErrorReissuable();
/**
* Wait for the replica DB to catch up to a given primary DB position
*
* Note that this does not start any new transactions. If any existing transaction
* is flushed, and this is called, then queries will reflect the point the DB was synced
* up to (on success) without interference from REPEATABLE-READ snapshots.
*
* @param DBPrimaryPos $pos
* @param int $timeout The maximum number of seconds to wait for synchronisation
* @return int|null Zero if the replica DB was past that position already,
* greater than zero if we waited for some period of time, less than
* zero if it timed out, and null on error
* @throws DBError If an error occurs, {@see query}
* @since 1.37
*/
public function primaryPosWait( DBPrimaryPos $pos, $timeout );
/**
* Get the replication position of this replica DB
*
* @return DBPrimaryPos|bool False if this is not a replica DB
* @throws DBError If an error occurs, {@see query}
*/
public function getReplicaPos();
/**
* Get the position of this primary DB
*
* @return DBPrimaryPos|bool False if this is not a primary DB
* @throws DBError If an error occurs, {@see query}
* @since 1.37
*/
public function getPrimaryPos();
/**
* @return bool Whether the DB is marked as read-only server-side
* @throws DBError If an error occurs, {@see query}
* @since 1.28
*/
public function serverIsReadOnly();
/**
* Run a callback when the current transaction commits or rolls back
*
* An error is thrown if no transaction is pending.
*
* When transaction round mode (DBO_TRX) is set, the callback will run at the end
* of the round, just after all peer transactions COMMIT/ROLLBACK.
*
* This IDatabase instance will start off in auto-commit mode when the callback starts.
* The use of other IDatabase handles from the callback should be avoided unless they are
* known to be in auto-commit mode. Callbacks that create transactions via begin() or
* startAtomic() must have matching calls to commit()/endAtomic().
*
* Use this method only for the following purposes:
* - (a) Release of cooperative locks on resources
* - (b) Cancellation of in-process deferred tasks
*
* The callback takes the following arguments:
* - How the current atomic section (if any) or overall transaction (otherwise) ended
* (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK)
* - This IDatabase instance (since 1.32)
*
* Callbacks will execute in the order they were enqueued.
*
* @note Use onAtomicSectionCancel() to take action as soon as an atomic section is cancelled
*
* @param callable $callback
* @param string $fname Caller name
* @throws DBError If an error occurs, {@see query}
* @throws Exception If the callback runs immediately and an error occurs in it
* @since 1.28
*/
public function onTransactionResolution( callable $callback, $fname = __METHOD__ );
/**
* Run a callback when the current transaction commits or now if there is none
*
* If there is a transaction and it is rolled back, then the callback is cancelled.
*
* When transaction round mode (DBO_TRX) is set, the callback will run at the end
* of the round, just after all peer transactions COMMIT. If the transaction round
* is rolled back, then the callback is cancelled.
*
* This IDatabase instance will start off in auto-commit mode when the callback starts.
* The use of other IDatabase handles from the callback should be avoided unless they are
* known to be in auto-commit mode. Callbacks that create transactions via begin() or
* startAtomic() must have matching calls to commit()/endAtomic().
*
* Use this method only for the following purposes:
* - (a) RDBMS updates, prone to lock timeouts/deadlocks, that do not require
* atomicity with respect to the updates in the current transaction (if any)
* - (b) Purges to lightweight cache services due to RDBMS updates
* - (c) Updates to secondary DBs/stores that must only commit once the updates in
* the current transaction (if any) are committed (e.g. insert user account row
* to DB1, then, initialize corresponding LDAP account)
*
* The callback takes the following arguments:
* - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_IDLE)
* - This IDatabase instance (since 1.32)
*
* Callbacks will execute in the order they were enqueued.
*
* @param callable $callback
* @param string $fname Caller name
* @throws DBError If an error occurs, {@see query}
* @throws Exception If the callback runs immediately and an error occurs in it
* @since 1.32
*/
public function onTransactionCommitOrIdle( callable $callback, $fname = __METHOD__ );
/**
* Run a callback before the current transaction commits or now if there is none
*
* If there is a transaction and it is rolled back, then the callback is cancelled.
*
* When transaction round mode (DBO_TRX) is set, the callback will run at the end
* of the round, just after all peer transactions COMMIT. If the transaction round
* is rolled back, then the callback is cancelled.
*
* If there is no current transaction, one will be created to wrap the callback.
* Callbacks cannot use begin()/commit() to manage transactions. The use of other
* IDatabase handles from the callback should be avoided.
*
* Use this method only for the following purposes:
* - a) RDBMS updates, prone to lock timeouts/deadlocks, that require atomicity
* with respect to the updates in the current transaction (if any)
* - b) Purges to lightweight cache services due to RDBMS updates
*
* The callback takes the one argument:
* - This IDatabase instance (since 1.32)
*
* Callbacks will execute in the order they were enqueued.
*
* @param callable $callback
* @param string $fname Caller name
* @throws DBError If an error occurs, {@see query}
* @throws Exception If the callback runs immediately and an error occurs in it
* @since 1.22
*/
public function onTransactionPreCommitOrIdle( callable $callback, $fname = __METHOD__ );
/**
* Run a callback when the atomic section is cancelled
*
* The callback is run just after the current atomic section, any outer
* atomic section, or the whole transaction is rolled back.
*
* An error is thrown if no atomic section is pending. The atomic section
* need not have been created with the ATOMIC_CANCELABLE flag.
*
* Queries in the function may be running in the context of an outer
* transaction or may be running in AUTOCOMMIT mode. The callback should
* use atomic sections if necessary.
*
* @note do not assume that *other* IDatabase instances will be AUTOCOMMIT mode
*
* The callback takes the following arguments:
* - IDatabase::TRIGGER_CANCEL or IDatabase::TRIGGER_ROLLBACK
* - This IDatabase instance
*
* @param callable $callback
* @param string $fname Caller name
* @since 1.34
*/
public function onAtomicSectionCancel( callable $callback, $fname = __METHOD__ );
/**
* Run a callback after each time any transaction commits or rolls back
*
* The callback takes two arguments:
* - IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK
* - This IDatabase object
* Callbacks must commit any transactions that they begin.
*
* Registering a callback here will not affect writesOrCallbacks() pending.
*
* Since callbacks from this or onTransactionCommitOrIdle() can start and end transactions,
* a single call to IDatabase::commit might trigger multiple runs of the listener callbacks.
*
* @param string $name Callback name
* @param callable|null $callback Use null to unset a listener
* @since 1.28
*/
public function setTransactionListener( $name, callable $callback = null );
/**
* Begin an atomic section of SQL statements
*
* Start an implicit transaction if no transaction is already active, set a savepoint
* (if $cancelable is ATOMIC_CANCELABLE), and track the given section name to enforce
* that the transaction is not committed prematurely. The end of the section must be
* signified exactly once, either by endAtomic() or cancelAtomic(). Sections can have
* have layers of inner sections (sub-sections), but all sections must be ended in order
* of innermost to outermost. Transactions cannot be started or committed until all
* atomic sections are closed.
*
* ATOMIC_CANCELABLE is useful when the caller needs to handle specific failure cases
* by discarding the section's writes. This should not be used for failures when:
* - upsert() could easily be used instead
* - insert() with IGNORE could easily be used instead
* - select() with FOR UPDATE could be checked before issuing writes instead
* - The failure is from code that runs after the first write but doesn't need to
* - The failures are from contention solvable via onTransactionPreCommitOrIdle()
* - The failures are deadlocks; the RDBMs usually discard the whole transaction
*
* @note callers must use additional measures for situations involving two or more
* (peer) transactions (e.g. updating two database servers at once). The transaction
* and savepoint logic of this method only applies to this specific IDatabase instance.
*
* Example usage:
* @code
* // Start a transaction if there isn't one already
* $dbw->startAtomic( __METHOD__ );
* // Serialize these thread table updates
* $dbw->select( 'thread', '1', [ 'td_id' => $tid ], __METHOD__, 'FOR UPDATE' );
* // Add a new comment for the thread
* $dbw->insert( 'comment', $row, __METHOD__ );
* $cid = $db->insertId();
* // Update thread reference to last comment
* $dbw->update( 'thread', [ 'td_latest' => $cid ], [ 'td_id' => $tid ], __METHOD__ );
* // Demark the end of this conceptual unit of updates
* $dbw->endAtomic( __METHOD__ );
* @endcode
*
* Example usage (atomic changes that might have to be discarded):
* @code
* // Start a transaction if there isn't one already
* $sectionId = $dbw->startAtomic( __METHOD__, $dbw::ATOMIC_CANCELABLE );
* // Create new record metadata row
* $dbw->insert( 'records', $row, __METHOD__ );
* // Figure out where to store the data based on the new row's ID
* $path = $recordDirectory . '/' . $dbw->insertId();
* // Write the record data to the storage system
* $status = $fileBackend->create( [ 'dst' => $path, 'content' => $data ] );
* if ( $status->isOK() ) {
* // Try to cleanup files orphaned by transaction rollback
* $dbw->onTransactionResolution(
* function ( $type ) use ( $fileBackend, $path ) {
* if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
* $fileBackend->delete( [ 'src' => $path ] );
* }
* },
* __METHOD__
* );
* // Demark the end of this conceptual unit of updates
* $dbw->endAtomic( __METHOD__ );
* } else {
* // Discard these writes from the transaction (preserving prior writes)
* $dbw->cancelAtomic( __METHOD__, $sectionId );
* }
* @endcode
*
* @since 1.23
* @param string $fname
* @param string $cancelable Pass self::ATOMIC_CANCELABLE to use a
* savepoint and enable self::cancelAtomic() for this section.
* @return AtomicSectionIdentifier section ID token
* @throws DBError If an error occurs, {@see query}
*/
public function startAtomic( $fname = __METHOD__, $cancelable = self::ATOMIC_NOT_CANCELABLE );
/**
* Ends an atomic section of SQL statements
*
* Ends the next section of atomic SQL statements and commits the transaction
* if necessary.
*
* @since 1.23
* @see IDatabase::startAtomic
* @param string $fname
* @throws DBError If an error occurs, {@see query}
*/
public function endAtomic( $fname = __METHOD__ );
/**
* Cancel an atomic section of SQL statements
*
* This will roll back only the statements executed since the start of the
* most recent atomic section, and close that section. If a transaction was
* open before the corresponding startAtomic() call, any statements before
* that call are *not* rolled back and the transaction remains open. If the
* corresponding startAtomic() implicitly started a transaction, that
* transaction is rolled back.
*
* @note callers must use additional measures for situations involving two or more
* (peer) transactions (e.g. updating two database servers at once). The transaction
* and savepoint logic of startAtomic() are bound to specific IDatabase instances.
*
* Note that a call to IDatabase::rollback() will also roll back any open atomic sections.
*
* @note As a micro-optimization to save a few DB calls, this method may only
* be called when startAtomic() was called with the ATOMIC_CANCELABLE flag.
* @since 1.31
* @see IDatabase::startAtomic
* @param string $fname
* @param AtomicSectionIdentifier|null $sectionId Section ID from startAtomic();
* passing this enables cancellation of unclosed nested sections [optional]
* @throws DBError If an error occurs, {@see query}
*/
public function cancelAtomic( $fname = __METHOD__, AtomicSectionIdentifier $sectionId = null );
/**
* Perform an atomic section of reversible SQL statements from a callback
*
* The $callback takes the following arguments:
* - This database object
* - The value of $fname
*
* This will execute the callback inside a pair of startAtomic()/endAtomic() calls.
* If any exception occurs during execution of the callback, it will be handled as follows:
* - If $cancelable is ATOMIC_CANCELABLE, cancelAtomic() will be called to back out any
* (and only) statements executed during the atomic section. If that succeeds, then the
* exception will be re-thrown; if it fails, then a different exception will be thrown
* and any further query attempts will fail until rollback() is called.
* - If $cancelable is ATOMIC_NOT_CANCELABLE, cancelAtomic() will be called to mark the
* end of the section and the error will be re-thrown. Any further query attempts will
* fail until rollback() is called.
*
* This method is convenient for letting calls to the caller of this method be wrapped
* in a try/catch blocks for exception types that imply that the caller failed but was
* able to properly discard the changes it made in the transaction. This method can be
* an alternative to explicit calls to startAtomic()/endAtomic()/cancelAtomic().
*
* Example usage, "RecordStore::save" method:
* @code
* $dbw->doAtomicSection( __METHOD__, function ( $dbw ) use ( $record ) {
* // Create new record metadata row
* $dbw->insert( 'records', $record->toArray(), __METHOD__ );
* // Figure out where to store the data based on the new row's ID
* $path = $this->recordDirectory . '/' . $dbw->insertId();
* // Write the record data to the storage system;
* // blob store throws StoreFailureException on failure
* $this->blobStore->create( $path, $record->getJSON() );
* // Try to cleanup files orphaned by transaction rollback
* $dbw->onTransactionResolution(
* function ( $type ) use ( $path ) {
* if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
* $this->blobStore->delete( $path );
* }
* },
* __METHOD__
* );
* }, $dbw::ATOMIC_CANCELABLE );
* @endcode
*
* Example usage, caller of the "RecordStore::save" method:
* @code
* $dbw->startAtomic( __METHOD__ );
* // ...various SQL writes happen...
* try {
* $recordStore->save( $record );
* } catch ( StoreFailureException $e ) {
* // ...various SQL writes happen...
* }
* // ...various SQL writes happen...
* $dbw->endAtomic( __METHOD__ );
* @endcode
*
* @see Database::startAtomic
* @see Database::endAtomic
* @see Database::cancelAtomic
*
* @param string $fname Caller name (usually __METHOD__)
* @param callable $callback Callback that issues DB updates
* @param string $cancelable Pass self::ATOMIC_CANCELABLE to use a
* savepoint and enable self::cancelAtomic() for this section.
* @return mixed Result of the callback (since 1.28)
* @throws DBError If an error occurs, {@see query}
* @throws Exception If an error occurs in the callback
* @since 1.27; prior to 1.31 this did a rollback() instead of
* cancelAtomic(), and assumed no callers up the stack would ever try to
* catch the exception.
*/
public function doAtomicSection(
$fname, callable $callback, $cancelable = self::ATOMIC_NOT_CANCELABLE
);
/**
* Begin a transaction
*
* Only call this from code with outer transaction scope.
* See https://www.mediawiki.org/wiki/Database_transactions for details.
* Nesting of transactions is not supported.
*
* Note that when the DBO_TRX flag is set (which is usually the case for web
* requests, but not for maintenance scripts), any previous database query
* will have started a transaction automatically.
*
* Nesting of transactions is not supported. Attempts to nest transactions
* will cause a warning, unless the current transaction was started
* automatically because of the DBO_TRX flag.
*
* @param string $fname Calling function name
* @param string $mode A situationally valid IDatabase::TRANSACTION_* constant [optional]
* @throws DBError If an error occurs, {@see query}
*/
public function begin( $fname = __METHOD__, $mode = self::TRANSACTION_EXPLICIT );
/**
* Commits a transaction previously started using begin()
*
* If no transaction is in progress, a warning is issued.
*
* Only call this from code with outer transaction scope.
* See https://www.mediawiki.org/wiki/Database_transactions for details.
* Nesting of transactions is not supported.
*
* @param string $fname
* @param string $flush Flush flag, set to situationally valid IDatabase::FLUSHING_*
* constant to disable warnings about explicitly committing implicit transactions,
* or calling commit when no transaction is in progress.
* This will trigger an exception if there is an ongoing explicit transaction.
* Only set the flush flag if you are sure that these warnings are not applicable,
* and no explicit transactions are open.
* @throws DBError If an error occurs, {@see query}
*/
public function commit( $fname = __METHOD__, $flush = self::FLUSHING_ONE );
/**
* Rollback a transaction previously started using begin()
*
* Only call this from code with outer transaction scope.
* See https://www.mediawiki.org/wiki/Database_transactions for details.
* Nesting of transactions is not supported. If a serious unexpected error occurs,
* throwing an Exception is preferable, using a pre-installed error handler to trigger
* rollback (in any case, failure to issue COMMIT will cause rollback server-side).
*
* Query, connection, and onTransaction* callback errors will be suppressed and logged.
*
* @param string $fname Calling function name
* @param string $flush Flush flag, set to a situationally valid IDatabase::FLUSHING_*
* constant to disable warnings about explicitly rolling back implicit transactions.
* This will silently break any ongoing explicit transaction. Only set the flush flag
* if you are sure that it is safe to ignore these warnings in your context.
* @throws DBError If an error occurs, {@see query}
* @since 1.23 Added $flush parameter
*/
public function rollback( $fname = __METHOD__, $flush = self::FLUSHING_ONE );
/**
* Release important session-level state (named lock, table locks) as post-rollback cleanup
*
* This should only be called by a load balancer or if the handle is not attached to one.
* Also, there must be no chance that a future caller will still be expecting some of the
* lost session state.
*
* Connection and query errors will be suppressed and logged
*
* @param string $fname Calling function name
* @param int|null $owner ID of the calling instance (e.g. the LBFactory ID)
* @throws DBError If an error occurs, {@see query}
* @since 1.38
*/
public function flushSession( $fname = __METHOD__, $owner = null );
/**
* Commit any transaction but error out if writes or callbacks are pending
*
* This is intended for clearing out REPEATABLE-READ snapshots so that callers can
* see a new point-in-time of the database. This is useful when one of many transaction
* rounds finished and significant time will pass in the script's lifetime. It is also
* useful to call on a replica DB after waiting on replication to catch up to the primary DB.
*
* @param string $fname Calling function name
* @param string $flush Flush flag, set to situationally valid IDatabase::FLUSHING_*
* constant to disable warnings about explicitly committing implicit transactions,
* or calling commit when no transaction is in progress.
* This will trigger an exception if there is an ongoing explicit transaction.
* Only set the flush flag if you are sure that these warnings are not applicable,
* and no explicit transactions are open.
* @throws DBError If an error occurs, {@see query}
* @since 1.28
* @since 1.34 Added $flush parameter
*/
public function flushSnapshot( $fname = __METHOD__, $flush = self::FLUSHING_ONE );
/**
* Convert a timestamp in one of the formats accepted by ConvertibleTimestamp
* to the format used for inserting into timestamp fields in this DBMS
*
* The result is unquoted, and needs to be passed through addQuotes()
* before it can be included in raw SQL.
*
* @param string|int $ts
*
* @return string
*/
public function timestamp( $ts = 0 );
/**
* Convert a timestamp in one of the formats accepted by ConvertibleTimestamp
* to the format used for inserting into timestamp fields in this DBMS
*
* If NULL is input, it is passed through, allowing NULL values to be inserted
* into timestamp fields.
*
* The result is unquoted, and needs to be passed through addQuotes()
* before it can be included in raw SQL.
*
* @param string|int|null $ts
*
* @return string|null
*/
public function timestampOrNull( $ts = null );
/**
* Ping the server and try to reconnect if it there is no connection
*
* @param float|null &$rtt Value to store the estimated RTT [optional]
* @return bool Success or failure
*/
public function ping( &$rtt = null );
/**
* Get the amount of replication lag for this database server
*
* Callers should avoid using this method while a transaction is active
*
* @return float|int|false Database replication lag in seconds or false on error
* @throws DBError If an error occurs, {@see query}
*/
public function getLag();
/**
* Get the replica DB lag when the current transaction started
* or a general lag estimate if not transaction is active
*
* This is useful when transactions might use snapshot isolation
* (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data
* is this lag plus transaction duration. If they don't, it is still
* safe to be pessimistic. In AUTOCOMMIT mode, this still gives an
* indication of the staleness of subsequent reads.
*
* @return array ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
* @throws DBError If an error occurs, {@see query}
* @since 1.27
*/
public function getSessionLagStatus();
/**
* Some DBMSs have a special format for inserting into blob fields, they
* don't allow simple quoted strings to be inserted. To insert into such
* a field, pass the data through this function before passing it to
* IDatabase::insert().
*
* @param string $b
* @return string|Blob
* @throws DBError
*/
public function encodeBlob( $b );
/**
* Some DBMSs return a special placeholder object representing blob fields
* in result objects. Pass the object through this function to return the
* original string.
*
* @param string|Blob $b
* @return string
* @throws DBError
*/
public function decodeBlob( $b );
/**
* Override database's default behavior. $options include:
* 'connTimeout' : Set the connection timeout value in seconds.
* May be useful for very long batch queries such as
* full-wiki dumps, where a single query reads out over
* hours or days.
*
* @param array $options
* @return void
* @throws DBError If an error occurs, {@see query}
*/
public function setSessionOptions( array $options );
/**
* Set schema variables to be used when streaming commands from SQL files or stdin
*
* Variables appear as SQL comments and are substituted by their corresponding values
*
* @param array|null $vars Map of (variable => value) or null to use the defaults
*/
public function setSchemaVars( $vars );
/**
* Check to see if a named lock is not locked by any thread (non-blocking)
*
* @param string $lockName Name of lock to poll
* @param string $method Name of method calling us
* @return bool
* @throws DBError If an error occurs, {@see query}
* @since 1.20
*/
public function lockIsFree( $lockName, $method );
/**
* Acquire a named lock
*
* Named locks are not related to transactions
*
* @param string $lockName Name of lock to acquire
* @param string $method Name of the calling method
* @param int $timeout Acquisition timeout in seconds (0 means non-blocking)
* @param int $flags Bit field of IDatabase::LOCK_* constants
* @return bool|float|null Success (bool); acquisition time (float/null) if LOCK_TIMESTAMP
* @throws DBError If an error occurs, {@see query}
*/
public function lock( $lockName, $method, $timeout = 5, $flags = 0 );
/**
* Release a lock
*
* Named locks are not related to transactions
*
* @param string $lockName Name of lock to release
* @param string $method Name of the calling method
* @return bool Success
* @throws DBError If an error occurs, {@see query}
*/
public function unlock( $lockName, $method );
/**
* Acquire a named lock, flush any transaction, and return an RAII style unlocker object
*
* Only call this from outer transaction scope and when only one DB will be affected.
* See https://www.mediawiki.org/wiki/Database_transactions for details.
*
* This is suitable for transactions that need to be serialized using cooperative locks,
* where each transaction can see each others' changes. Any transaction is flushed to clear
* out stale REPEATABLE-READ snapshot data. Once the returned object falls out of PHP scope,
* the lock will be released unless a transaction is active. If one is active, then the lock
* will be released when it either commits or rolls back.
*
* If the lock acquisition failed, then no transaction flush happens, and null is returned.
*
* @param string $lockKey Name of lock to release
* @param string $fname Name of the calling method
* @param int $timeout Acquisition timeout in seconds
* @return ScopedCallback|null
* @throws DBError If an error occurs, {@see query}
* @since 1.27
*/
public function getScopedLockAndFlush( $lockKey, $fname, $timeout );
/**
* Check to see if a named lock used by lock() use blocking queues
*
* @return bool
* @since 1.26
*/
public function namedLocksEnqueue();
/**
* Find out when 'infinity' is. Most DBMSes support this. This is a special
* keyword for timestamps in PostgreSQL, and works with CHAR(14) as well
* because "i" sorts after all numbers.
*
* @return string
*/
public function getInfinity();
/**
* Encode an expiry time into the DBMS dependent format
*
* @param string $expiry Timestamp for expiry, or the 'infinity' string
* @return string
*/
public function encodeExpiry( $expiry );
/**
* Decode an expiry time into a DBMS independent format
*
* @param string $expiry DB timestamp field value for expiry
* @param int $format TS_* constant, defaults to TS_MW
* @return string
*/
public function decodeExpiry( $expiry, $format = TS_MW );
/**
* Allow or deny "big selects" for this session only. This is done by setting
* the sql_big_selects session variable.
*
* This is a MySQL-specific feature.
*
* @param bool|string $value True for allow, false for deny, or "default" to
* restore the initial value
*/
public function setBigSelects( $value = true );
/**
* @return bool Whether this DB is read-only
* @since 1.27
*/
public function isReadOnly();
/**
* Make certain table names use their own database, schema, and table prefix
* when passed into SQL queries pre-escaped and without a qualified database name
*
* For example, "user" can be converted to "myschema.mydbname.user" for convenience.
* Appearances like `user`, somedb.user, somedb.someschema.user will used literally.
*
* Calling this twice will completely clear any old table aliases. Also, note that
* callers are responsible for making sure the schemas and databases actually exist.
*
* @param array[] $aliases Map of (table => (dbname, schema, prefix) map)
* @since 1.28
*/
public function setTableAliases( array $aliases );
/**
* Convert certain index names to alternative names before querying the DB
*
* Note that this applies to indexes regardless of the table they belong to.
*
* This can be employed when an index was renamed X => Y in code, but the new Y-named
* indexes were not yet built on all DBs. After all the Y-named ones are added by the DBA,
* the aliases can be removed, and then the old X-named indexes dropped.
*
* @param string[] $aliases
* @since 1.31
*/
public function setIndexAliases( array $aliases );
/**
* Get a debugging string that mentions the database type, the ID of this instance,
* and the ID of any underlying connection resource or driver object if one is present
*
* @return string "<db type> object #<X>" or "<db type> object #<X> (resource/handle id #<Y>)"
* @since 1.34
*/
public function __toString();
}
/**
* @deprecated since 1.29
*/
class_alias( IDatabase::class, 'IDatabase' );
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