fieldname, with fields acting like * member variables. If no more rows are available, false is returned. * * @param IResultWrapper|stdClass $res Object as returned from IDatabase::query(), etc. * @return stdClass|bool */ public function fetchObject( $res ); /** * Fetch the next row from the given result object, in associative array form * * Fields are retrieved with $row['fieldname']. * If no more rows are available, false is returned. * * @param IResultWrapper $res Result object as returned from IDatabase::query(), etc. * @return array|bool */ public function fetchRow( $res ); /** * Get the number of rows in a query result * * Returns zero if the query did not return any rows or was a write query. * * @param mixed $res A SQL result * @return int */ public function numRows( $res ); /** * Get the number of fields in a result object * @see https://www.php.net/mysql_num_fields * * @param mixed $res A SQL result * @return int */ public function numFields( $res ); /** * Get a field name in a result object * @see https://www.php.net/mysql_field_name * * @param mixed $res A SQL result * @param int $n * @return string */ public function fieldName( $res, $n ); /** * 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(); /** * Change the position of the cursor in a result object * @see https://www.php.net/mysql_data_seek * * @param mixed $res A SQL result * @param int $row */ public function dataSeek( $res, $row ); /** * 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 Bitfield 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 ); /** * Free a result object returned by query() or select() * * It's usually not necessary to call this, just use unset() or let the variable * holding the result object go out of scope. * * @param mixed $res A SQL result */ public function freeResult( $res ); /** * Create an empty SelectQueryBuilder which can be used to run queries * against this connection. * * @return SelectQueryBuilder */ public function newSelectQueryBuilder(); /** * 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 IDatabase::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 IDatabase::select() for details. * @param string $fname The function name of the caller. * @param string|array $options The query options. See IDatabase::select() for details. * @param string|array $join_conds The query join conditions. See IDatabase::select() for details. * @return mixed The value from the field * @throws DBError If an error occurs, see IDatabase::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 IDatabase::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 IDatabase::select() for details. * @param string $fname The function name of the caller. * @param string|array $options The query options. See IDatabase::select() for details. * @param string|array $join_conds The query join conditions. See IDatabase::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 IDatabase::query() * @since 1.25 */ public function selectFieldValues( $table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = [] ); /** * 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. * * @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. * * 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. In the * most common case, this is unnecessary, since the join condition can be * in $conds. However, it is useful for doing a LEFT JOIN. * * 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 IDatabase::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 IDatabase::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 IDatabase::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 IDatabase::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 IDatabase::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 Filed to check on that table * @param string $fname Calling function name (optional) * @return bool Whether $table has filed $field * @throws DBError If an error occurs, see IDatabase::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 IDatabase::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 IDatabase::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 IDatabase::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 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 IDatabase::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 IDatabase::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 IDatabase::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 ); /** * Return aggregated value alias * * @param array $valuedata * @param string $valuename * * @return array|string * @deprecated Since 1.33 */ public function aggregateValue( $valuedata, $valuename = 'value' ); /** * @param string|int $field * @return string */ public function bitNot( $field ); /** * @param string|int $fieldLeft * @param string|int $fieldRight * @return string */ public function bitAnd( $fieldLeft, $fieldRight ); /** * @param string|int $fieldLeft * @param string|int $fieldRight * @return string */ public function bitOr( $fieldLeft, $fieldRight ); /** * 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 DB name * @return string|null */ public function getDBname(); /** * Get the server hostname or IP address * @return string */ public function getServer(); /** * 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 ); /** * Escape a SQL identifier (e.g. table, column, database) for use in a SQL query * * Depending on the database this will either be `backticks` or "double quotes" * * @param string $s * @return string * @since 1.33 */ public function addIdentifierQuotes( $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. 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 $uniqueIndexes 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 IDatabase::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 $uniqueIndexes 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. 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 $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 * modified AUTOINCREMENT or UUID columns in assignments. * @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 IDatabase::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 IDatabase::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 explicitely 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 IDatabase::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 IDatabase::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 expression which will result in a boolean value * @param string $trueVal SQL expression to return if true * @param string $falseVal SQL expression to return if false * @return string SQL fragment */ public function conditional( $cond, $trueVal, $falseVal ); /** * 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 how long the server has been up * * @return int * @throws DBError */ public function getServerUptime(); /** * 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 master 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 DBMasterPos $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 IDatabase::query() */ public function masterPosWait( DBMasterPos $pos, $timeout ); /** * Get the replication position of this replica DB * * @return DBMasterPos|bool False if this is not a replica DB * @throws DBError If an error occurs, see IDatabase::query() */ public function getReplicaPos(); /** * Get the position of this master * * @return DBMasterPos|bool False if this is not a master * @throws DBError If an error occurs, see IDatabase::query() */ public function getMasterPos(); /** * @return bool Whether the DB is marked as read-only server-side * @since 1.28 */ public function serverIsReadOnly(); /** * Run a callback as soon as the current transaction commits or rolls back * * An error is thrown if no transaction is pending. Queries in the function will run in * AUTOCOMMIT mode unless there are begin() calls. Callbacks must commit any transactions * that they begin. * * This is useful for combining cooperative locks and DB transactions. * * Note this is called when the whole transaction is resolved. To take action immediately * when an atomic section is cancelled, use onAtomicSectionCancel(). * * @note do not assume that *other* IDatabase instances will be AUTOCOMMIT mode * * The callback takes the following arguments: * - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK) * - This IDatabase instance (since 1.32) * * @param callable $callback * @param string $fname Caller name * @throws DBError If an error occurs, see IDatabase::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 as soon as there is no transaction pending * * 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. * * Queries in the function will run in AUTOCOMMIT mode unless there are begin() calls. * Callbacks must commit any transactions that they begin. * * This is useful for updates to different systems or when separate transactions are needed. * For example, one might want to enqueue jobs into a system outside the database, but only * after the database is updated so that the jobs will see the data when they actually run. * It can also be used for updates that easily suffer from lock timeouts and deadlocks, * but where atomicity is not essential. * * Avoid using IDatabase instances aside from this one in the callback, unless such instances * never have IDatabase::DBO_TRX set. This keeps callbacks from interfering with one another. * * Updates will execute in the order they were enqueued. * * @note do not assume that *other* IDatabase instances will be AUTOCOMMIT mode * * The callback takes the following arguments: * - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_IDLE) * - This IDatabase instance (since 1.32) * * @param callable $callback * @param string $fname Caller name * @throws DBError If an error occurs, see IDatabase::query() * @throws Exception If the callback runs immediately and an error occurs in it * @since 1.32 */ public function onTransactionCommitOrIdle( callable $callback, $fname = __METHOD__ ); /** * Alias for onTransactionCommitOrIdle() for backwards-compatibility * * @param callable $callback * @param string $fname * @since 1.20 * @deprecated Since 1.32 */ public function onTransactionIdle( 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 before all peer transactions COMMIT. If the transaction round * is rolled back, then the callback is cancelled. * * Callbacks must not start nor commit any transactions. If no transaction is active, * then a transaction will wrap the callback. * * This is useful for updates that easily suffer from lock timeouts and deadlocks, * but where atomicity is strongly desired for these updates and some related updates. * * Updates will execute in the order they were enqueued. * * The callback takes the one argument: * - This IDatabase instance (since 1.32) * * @param callable $callback * @param string $fname Caller name * @throws DBError If an error occurs, see IDatabase::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 IDatabase::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 IDatabase::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 IDatabase::query() */ public function cancelAtomic( $fname = __METHOD__, AtomicSectionIdentifier $sectionId = null ); /** * Perform an atomic section of reversable 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 throughs 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 $res Result of the callback (since 1.28) * @throws DBError If an error occurs, see IDatabase::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 transcation 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 IDatabase::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 transcation 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 IDatabase::query() */ public function commit( $fname = __METHOD__, $flush = self::FLUSHING_ONE ); /** * Rollback a transaction previously started using begin() * * Only call this from code with outer transcation 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 preferrable, 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 calling rollback when no transaction is in * progress. 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 IDatabase::query() * @since 1.23 Added $flush parameter */ public function rollback( $fname = __METHOD__, $flush = self::FLUSHING_ONE ); /** * 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 master. * * @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 IDatabase::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 int|bool Database replication lag in seconds or false on error * @throws DBError If an error occurs, see IDatabase::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 IDatabase::query() * @since 1.27 */ public function getSessionLagStatus(); /** * Return the maximum number of items allowed in a list, or 0 for unlimited * * @return int */ public function maxListLen(); /** * 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 IDatabase::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 IDatabase::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 aquire * @param string $method Name of the calling method * @param int $timeout Acquisition timeout in seconds (0 means non-blocking) * @return bool Success * @throws DBError If an error occurs, see IDatabase::query() */ public function lock( $lockName, $method, $timeout = 5 ); /** * 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 IDatabase::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 transcation scope and when only one DB will be affected. * See https://www.mediawiki.org/wiki/Database_transactions for details. * * This is suitiable 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 IDatabase::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 " object #" or " object # (resource/handle id #)" * @since 1.34 */ public function __toString(); } /** * @deprecated since 1.29 */ class_alias( IDatabase::class, 'IDatabase' );