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DatabaseBase Class Reference
Inheritance diagram for DatabaseBase:
Collaboration diagram for DatabaseBase:

Public Member Functions

 getServerInfo ()
 
 getDelimiter ()
 
 debug ($debug=null)
 
 bufferResults ($buffer=null)
 
 trxLevel ()
 
 trxTimestamp ()
 
 tablePrefix ($prefix=null)
 
 dbSchema ($schema=null)
 
 setFileHandle ($fh)
 
 getLBInfo ($name=null)
 
 setLBInfo ($name, $value=null)
 
 setLazyMasterHandle (IDatabase $conn)
 
 getLazyMasterHandle ()
 
 setTransactionProfiler (TransactionProfiler $profiler)
 
 cascadingDeletes ()
 
 cleanupTriggers ()
 
 strictIPs ()
 
 realTimestamps ()
 
 implicitGroupby ()
 
 implicitOrderby ()
 
 searchableIPs ()
 
 functionalIndexes ()
 
 lastQuery ()
 
 doneWrites ()
 
 lastDoneWrites ()
 
 writesPending ()
 
 writesOrCallbacksPending ()
 
 pendingWriteQueryDuration ()
 
 pendingWriteCallers ()
 
 isOpen ()
 
 setFlag ($flag)
 
 clearFlag ($flag)
 
 getFlag ($flag)
 
 getProperty ($name)
 
 getWikiID ()
 
 getSchemaPath ()
 
 getUpdateKeysPath ()
 
 indexInfo ($table, $index, $fname=__METHOD__)
 
 strencode ($s)
 
 __construct (array $params)
 
 __sleep ()
 
 connectionErrorHandler ($errno, $errstr)
 
 close ()
 
 reportConnectionError ($error= 'Unknown error')
 
 query ($sql, $fname=__METHOD__, $tempIgnore=false)
 
 reportQueryError ($error, $errno, $sql, $fname, $tempIgnore=false)
 
 execute ($prepared, $args=null)
 
 fillPrepared ($preparedQuery, $args)
 
 freeResult ($res)
 
 selectField ($table, $var, $cond= '', $fname=__METHOD__, $options=[])
 
 selectFieldValues ($table, $var, $cond= '', $fname=__METHOD__, $options=[], $join_conds=[])
 
 makeSelectOptions ($options)
 
 makeGroupByWithHaving ($options)
 
 makeOrderBy ($options)
 
 select ($table, $vars, $conds= '', $fname=__METHOD__, $options=[], $join_conds=[])
 
 selectSQLText ($table, $vars, $conds= '', $fname=__METHOD__, $options=[], $join_conds=[])
 
 selectRow ($table, $vars, $conds, $fname=__METHOD__, $options=[], $join_conds=[])
 
 estimateRowCount ($table, $vars= '*', $conds= '', $fname=__METHOD__, $options=[])
 
 selectRowCount ($tables, $vars= '*', $conds= '', $fname=__METHOD__, $options=[], $join_conds=[])
 
 fieldExists ($table, $field, $fname=__METHOD__)
 
 indexExists ($table, $index, $fname=__METHOD__)
 
 tableExists ($table, $fname=__METHOD__)
 
 indexUnique ($table, $index)
 
 insert ($table, $a, $fname=__METHOD__, $options=[])
 
 update ($table, $values, $conds, $fname=__METHOD__, $options=[])
 
 makeList ($a, $mode=LIST_COMMA)
 
 makeWhereFrom2d ($data, $baseKey, $subKey)
 
 aggregateValue ($valuedata, $valuename= 'value')
 
 bitNot ($field)
 
 bitAnd ($fieldLeft, $fieldRight)
 
 bitOr ($fieldLeft, $fieldRight)
 
 buildConcat ($stringList)
 
 buildGroupConcatField ($delim, $table, $field, $conds= '', $join_conds=[])
 
 selectDB ($db)
 
 getDBname ()
 
 getServer ()
 
 tableName ($name, $format= 'quoted')
 
 tableNames ()
 
 tableNamesN ()
 
 tableNameWithAlias ($name, $alias=false)
 
 tableNamesWithAlias ($tables)
 
 fieldNameWithAlias ($name, $alias=false)
 
 fieldNamesWithAlias ($fields)
 
 addQuotes ($s)
 
 addIdentifierQuotes ($s)
 
 isQuotedIdentifier ($name)
 
 buildLike ()
 
 anyChar ()
 
 anyString ()
 
 nextSequenceValue ($seqName)
 
 useIndexClause ($index)
 
 replace ($table, $uniqueIndexes, $rows, $fname=__METHOD__)
 
 upsert ($table, array $rows, array $uniqueIndexes, array $set, $fname=__METHOD__)
 
 deleteJoin ($delTable, $joinTable, $delVar, $joinVar, $conds, $fname=__METHOD__)
 
 textFieldSize ($table, $field)
 
 lowPriorityOption ()
 
 delete ($table, $conds, $fname=__METHOD__)
 
 insertSelect ($destTable, $srcTable, $varMap, $conds, $fname=__METHOD__, $insertOptions=[], $selectOptions=[])
 
 limitResult ($sql, $limit, $offset=false)
 
 unionSupportsOrderAndLimit ()
 
 unionQueries ($sqls, $all)
 
 conditional ($cond, $trueVal, $falseVal)
 
 strreplace ($orig, $old, $new)
 
 getServerUptime ()
 
 wasDeadlock ()
 
 wasLockTimeout ()
 
 wasErrorReissuable ()
 
 wasReadOnlyError ()
 
 wasConnectionError ($errno)
 
 masterPosWait (DBMasterPos $pos, $timeout)
 
 getSlavePos ()
 
 getMasterPos ()
 
 onTransactionIdle ($callback)
 
 onTransactionPreCommitOrIdle ($callback)
 
 startAtomic ($fname=__METHOD__)
 
 endAtomic ($fname=__METHOD__)
 
 doAtomicSection ($fname, $callback)
 
 begin ($fname=__METHOD__)
 
 commit ($fname=__METHOD__, $flush= '')
 
 rollback ($fname=__METHOD__, $flush= '')
 
 duplicateTableStructure ($oldName, $newName, $temporary=false, $fname=__METHOD__)
 
 listTables ($prefix=null, $fname=__METHOD__)
 
 clearViewsCache ()
 
 listViews ($prefix=null, $fname=__METHOD__)
 
 isView ($name)
 
 timestamp ($ts=0)
 
 timestampOrNull ($ts=null)
 
 ping ()
 
 getSessionLagStatus ()
 
 getTransactionLagStatus ()
 
 getApproximateLagStatus ()
 
 getLag ()
 
 maxListLen ()
 
 encodeBlob ($b)
 
 decodeBlob ($b)
 
 setSessionOptions (array $options)
 
 sourceFile ($filename, $lineCallback=false, $resultCallback=false, $fname=false, $inputCallback=false)
 
 patchPath ($patch)
 
 setSchemaVars ($vars)
 
 sourceStream ($fp, $lineCallback=false, $resultCallback=false, $fname=__METHOD__, $inputCallback=false)
 
 streamStatementEnd (&$sql, &$newLine)
 
 lockIsFree ($lockName, $method)
 
 lock ($lockName, $method, $timeout=5)
 
 unlock ($lockName, $method)
 
 getScopedLockAndFlush ($lockKey, $fname, $timeout)
 
 namedLocksEnqueue ()
 
 lockTables ($read, $write, $method, $lowPriority=true)
 
 unlockTables ($method)
 
 dropTable ($tableName, $fName=__METHOD__)
 
 getSearchEngine ()
 
 getInfinity ()
 
 encodeExpiry ($expiry)
 
 decodeExpiry ($expiry, $format=TS_MW)
 
 setBigSelects ($value=true)
 
 isReadOnly ()
 
 __toString ()
 
 __destruct ()
 
- Public Member Functions inherited from IDatabase
 getType ()
 
 open ($server, $user, $password, $dbName)
 
 fetchObject ($res)
 
 fetchRow ($res)
 
 numRows ($res)
 
 numFields ($res)
 
 fieldName ($res, $n)
 
 insertId ()
 
 dataSeek ($res, $row)
 
 lastErrno ()
 
 lastError ()
 
 fieldInfo ($table, $field)
 
 affectedRows ()
 
 getSoftwareLink ()
 
 getServerVersion ()
 
 selectFieldValues ($table, $var, $cond= '', $fname=__METHOD__, $options=[])
 

Static Public Member Functions

static factory ($dbType, $p=[])
 

Public Attributes

const DEADLOCK_TRIES = 4
 
const DEADLOCK_DELAY_MIN = 500000
 
const DEADLOCK_DELAY_MAX = 1500000
 
 $mUser
 
 $mPassword
 
 $mDBname
 

Protected Member Functions

 ignoreErrors ($ignoreErrors=null)
 
 getTransactionProfiler ()
 
 installErrorHandler ()
 
 restoreErrorHandler ()
 
 getLogContext (array $extras=[])
 
 assertOpen ()
 
 closeConnection ()
 
 doQuery ($sql)
 
 isWriteQuery ($sql)
 
 isTransactableQuery ($sql)
 
 prepare ($sql, $func= 'DatabaseBase::prepare')
 
 freePrepared ($prepared)
 
 fillPreparedArg ($matches)
 
 makeInsertOptions ($options)
 
 makeUpdateOptionsArray ($options)
 
 makeUpdateOptions ($options)
 
 tableNamesWithUseIndexOrJOIN ($tables, $use_index=[], $join_conds=[])
 
 indexName ($index)
 
 escapeLikeInternal ($s)
 
 nativeReplace ($table, $rows, $fname)
 
 runOnTransactionIdleCallbacks ()
 
 runOnTransactionPreCommitCallbacks ()
 
 doBegin ($fname)
 
 doCommit ($fname)
 
 doRollback ($fname)
 
 resultObject ($result)
 
 replaceVars ($ins)
 
 getSchemaVars ()
 
 getDefaultSchemaVars ()
 
 getReadOnlyReason ()
 

Static Protected Member Functions

static generalizeSQL ($sql)
 

Protected Attributes

 $mLastQuery = ''
 
 $mDoneWrites = false
 
 $mPHPError = false
 
 $mServer
 
 $srvCache
 
 $mConn = null
 
 $mOpened = false
 
 $mTrxIdleCallbacks = []
 
 $mTrxPreCommitCallbacks = []
 
 $mTablePrefix
 
 $mSchema
 
 $mFlags
 
 $mForeign
 
 $mLBInfo = []
 
 $mDefaultBigSelects = null
 
 $mSchemaVars = false
 
 $mSessionVars = []
 
 $preparedArgs
 
 $htmlErrors
 
 $delimiter = ';'
 
 $mTrxLevel = 0
 
 $mTrxShortId = ''
 
 $fileHandle = null
 
 $allViews = null
 
 $trxProfiler
 

Detailed Description

Database abstraction object

Constructor & Destructor Documentation

DatabaseBase::__construct ( array  $params)

Constructor.

FIXME: It is possible to construct a Database object with no associated connection object, by specifying no parameters to __construct(). This feature is deprecated and should be removed.

DatabaseBase subclasses should not be constructed directly in external code. DatabaseBase::factory() should be used instead.

Parameters
array$paramsParameters passed from DatabaseBase::factory()

Get the default table prefix

Get the database schema

DatabaseBase::__destruct ( )

Run a few simple sanity checks

Member Function Documentation

DatabaseBase::__sleep ( )

Called by serialize. Throw an exception when DB connection is serialized. This causes problems on some database engines because the connection is not restored on unserialize.

DatabaseBase::__toString ( )
Since
1.19
Returns
string
DatabaseBase::addIdentifierQuotes (   $s)

Quotes an identifier using backticks or "double quotes" depending on the database type. MySQL uses backticks while basically everything else uses double quotes. Since MySQL is the odd one out here the double quotes are our generic and we implement backticks in DatabaseMysql.

Parameters
string$s
Returns
string
DatabaseBase::addQuotes (   $s)

Adds quotes and backslashes.

Parameters
string | Blob$s
Returns
string

Implements IDatabase.

DatabaseBase::aggregateValue (   $valuedata,
  $valuename = 'value' 
)

Return aggregated value alias

Parameters
array$valuedata
string$valuename
Returns
string
DatabaseBase::anyChar ( )

Returns a token for buildLike() that denotes a '_' to be used in a LIKE query

Returns
LikeMatch

Implements IDatabase.

DatabaseBase::anyString ( )

Returns a token for buildLike() that denotes a '' to be used in a LIKE query

Returns
LikeMatch

Implements IDatabase.

DatabaseBase::assertOpen ( )
protected

Make sure isOpen() returns true as a sanity check

Exceptions
DBUnexpectedError
DatabaseBase::begin (   $fname = __METHOD__)
final

Begin a transaction. If a transaction is already in progress, that transaction will be committed before the new transaction is started.

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.

Parameters
string$fname
Exceptions
DBError

Implements IDatabase.

DatabaseBase::bitAnd (   $fieldLeft,
  $fieldRight 
)
Parameters
string$fieldLeft
string$fieldRight
Returns
string

Implements IDatabase.

DatabaseBase::bitNot (   $field)
Parameters
string$field
Returns
string

Implements IDatabase.

DatabaseBase::bitOr (   $fieldLeft,
  $fieldRight 
)
Parameters
string$fieldLeft
string$fieldRight
Returns
string

Implements IDatabase.

DatabaseBase::bufferResults (   $buffer = null)

Turns buffering of SQL result sets on (true) or off (false). Default is "on".

Unbuffered queries are very troublesome in MySQL:

  • If another query is executed while the first query is being read out, the first query is killed. This means you can't call normal MediaWiki functions while you are reading an unbuffered query result from a normal wfGetDB() connection.
  • Unbuffered queries cause the MySQL server to use large amounts of memory and to hold broad locks which block other queries.

If you want to limit client-side memory, it's almost always better to split up queries into batches using a LIMIT clause than to switch off buffering.

Parameters
null | bool$buffer
Returns
null|bool The previous value of the flag

Implements IDatabase.

DatabaseBase::buildConcat (   $stringList)

Build a concatenation list to feed into a SQL query

Parameters
array$stringListList of raw SQL expressions; caller is responsible for any quoting
Returns
string

Implements IDatabase.

DatabaseBase::buildGroupConcatField (   $delim,
  $table,
  $field,
  $conds = '',
  $join_conds = [] 
)

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.

Parameters
string$delimGlue to bind the results together
string | array$tableTable name
string$fieldField name
string | array$condsConditions
string | array$join_condsJoin conditions
Returns
string SQL text
Since
1.23

Implements IDatabase.

DatabaseBase::buildLike ( )

LIKE statement wrapper, receives 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 = array( 'My_page_title/', $dbr->anyString() ); $query .= $dbr->buildLike( $pattern );

Since
1.16
Returns
string Fully built LIKE statement

Implements IDatabase.

DatabaseBase::cascadingDeletes ( )

Returns true if this database supports (and uses) cascading deletes

Returns
bool
DatabaseBase::cleanupTriggers ( )

Returns true if this database supports (and uses) triggers (e.g. on the page table)

Returns
bool
DatabaseBase::clearFlag (   $flag)

Clear a flag for this connection

Parameters
int$flagDBO_* constants from Defines.php:
  • DBO_DEBUG: output some debug info (same as debug())
  • DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
  • DBO_TRX: automatically start transactions
  • DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode and removes it in command line mode
  • DBO_PERSISTENT: use persistant database connection

Implements IDatabase.

DatabaseBase::clearViewsCache ( )
final

Reset the views process cache set by listViews()

Since
1.22
DatabaseBase::close ( )

Closes a database connection. if it is open : commits any open transactions

Exceptions
MWException
Returns
bool Operation success. true if already closed.

Implements IDatabase.

DatabaseBase::closeConnection ( )
abstractprotected

Closes underlying database connection

Since
1.20
Returns
bool Whether connection was closed successfully
DatabaseBase::commit (   $fname = __METHOD__,
  $flush = '' 
)
final

Commits a transaction previously started using begin(). If no transaction is in progress, a warning is issued.

Nesting of transactions is not supported.

Parameters
string$fname
string$flushFlush flag, set to 'flush' 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.

Exceptions
DBUnexpectedError

Implements IDatabase.

DatabaseBase::conditional (   $cond,
  $trueVal,
  $falseVal 
)

Returns an SQL expression for a simple conditional. This doesn't need to be overridden unless CASE isn't supported in your DBMS.

Parameters
string | array$condSQL expression which will result in a boolean value
string$trueValSQL expression to return if true
string$falseValSQL expression to return if false
Returns
string SQL fragment

Implements IDatabase.

DatabaseBase::connectionErrorHandler (   $errno,
  $errstr 
)
Parameters
int$errno
string$errstr
DatabaseBase::dbSchema (   $schema = null)

Get/set the db schema.

Parameters
string$schemaThe database schema to set, or omitted to leave it unchanged.
Returns
string The previous db schema.

Implements IDatabase.

DatabaseBase::debug (   $debug = null)

Boolean, controls output of large amounts of debug information.

Parameters
bool | null$debug
  • true to enable debugging
  • false to disable debugging
  • omitted or null to do nothing
Returns
bool|null Previous value of the flag
DatabaseBase::decodeBlob (   $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.

Parameters
string | Blob$b
Returns
string

Implements IDatabase.

DatabaseBase::decodeExpiry (   $expiry,
  $format = TS_MW 
)

Decode an expiry time into a DBMS independent format

Parameters
string$expiryDB timestamp field value for expiry
int$formatTS_* constant, defaults to TS_MW
Returns
string

Implements IDatabase.

DatabaseBase::delete (   $table,
  $conds,
  $fname = __METHOD__ 
)

DELETE query wrapper.

Parameters
array$tableTable name
string | array$condsArray of conditions. See $conds in IDatabase::select() for the format. Use $conds == "*" to delete all rows
string$fnameName of the calling function
Exceptions
DBUnexpectedError
Returns
bool|ResultWrapper

Implements IDatabase.

DatabaseBase::deleteJoin (   $delTable,
  $joinTable,
  $delVar,
  $joinVar,
  $conds,
  $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='*'.

DO NOT put the join condition in $conds.

Parameters
string$delTableThe table to delete from.
string$joinTableThe other table.
string$delVarThe variable to join on, in the first table.
string$joinVarThe variable to join on, in the second table.
array$condsCondition array of field names mapped to variables, ANDed together in the WHERE clause
string$fnameCalling function name (use METHOD) for logs/profiling
Exceptions
DBUnexpectedError

Implements IDatabase.

DatabaseBase::doAtomicSection (   $fname,
  $callback 
)
final

Run a callback to do an atomic set of updates for this database

The $callback takes the following arguments:

  • This database object
  • The value of $fname

If any exception occurs in the callback, then rollback() will be called and the error will be re-thrown. It may also be that the rollback itself fails with an exception before then. In any case, such errors are expected to terminate the request, without any outside caller attempting to catch errors and commit anyway. Note that any rollback undoes all prior atomic section and uncommitted updates, which trashes the current request, requiring an error to be displayed.

This can be an alternative to explicit startAtomic()/endAtomic() calls.

See Also
DatabaseBase::startAtomic
DatabaseBase::endAtomic
Parameters
string$fnameCaller name (usually METHOD)
callable$callbackCallback that issues DB updates
Exceptions
DBError
RuntimeException
UnexpectedValueException
Since
1.27

Implements IDatabase.

DatabaseBase::doBegin (   $fname)
protected

Issues the BEGIN command to the database server.

See Also
DatabaseBase::begin()
Parameters
string$fname
DatabaseBase::doCommit (   $fname)
protected

Issues the COMMIT command to the database server.

See Also
DatabaseBase::commit()
Parameters
string$fname
DatabaseBase::doneWrites ( )

Returns true if the connection may have been used for write queries. Should return true if unsure.

Returns
bool

Implements IDatabase.

DatabaseBase::doQuery (   $sql)
abstractprotected

The DBMS-dependent part of query()

Parameters
string$sqlSQL query.
Returns
ResultWrapper|bool Result object to feed to fetchObject, fetchRow, ...; or false on failure
DatabaseBase::doRollback (   $fname)
protected

Issues the ROLLBACK command to the database server.

See Also
DatabaseBase::rollback()
Parameters
string$fname
DatabaseBase::dropTable (   $tableName,
  $fName = __METHOD__ 
)

Delete a table

Parameters
string$tableName
string$fName
Returns
bool|ResultWrapper
Since
1.18
DatabaseBase::duplicateTableStructure (   $oldName,
  $newName,
  $temporary = false,
  $fname = __METHOD__ 
)

Creates a new table with structure copied from existing table Note that unlike most database abstraction functions, this function does not automatically append database prefix, because it works at a lower abstraction level. The table names passed to this function shall not be quoted (this function calls addIdentifierQuotes when needed).

Parameters
string$oldNameName of table whose structure should be copied
string$newNameName of table to be created
bool$temporaryWhether the new table should be temporary
string$fnameCalling function name
Exceptions
MWException
Returns
bool True if operation was successful
DatabaseBase::encodeBlob (   $b)

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().

Parameters
string$b
Returns
string

Implements IDatabase.

DatabaseBase::encodeExpiry (   $expiry)

Encode an expiry time into the DBMS dependent format

Parameters
string$expiryTimestamp for expiry, or the 'infinity' string
Returns
string

Implements IDatabase.

DatabaseBase::endAtomic (   $fname = __METHOD__)
final

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 Also
IDatabase::startAtomic
Parameters
string$fname
Exceptions
DBError

Implements IDatabase.

DatabaseBase::escapeLikeInternal (   $s)
protected
Parameters
string$s
Returns
string
DatabaseBase::estimateRowCount (   $table,
  $vars = '*',
  $conds = '',
  $fname = __METHOD__,
  $options = [] 
)

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().

Parameters
string$tableTable name
string$varsUnused
array | string$condsFilters on the table
string$fnameFunction name for profiling
array$optionsOptions for select
Returns
int Row count

Implements IDatabase.

DatabaseBase::execute (   $prepared,
  $args = null 
)

Execute a prepared query with the various arguments

Parameters
string$preparedThe prepared sql
mixed$argsEither an array here, or put scalars as varargs
Returns
ResultWrapper
static DatabaseBase::factory (   $dbType,
  $p = [] 
)
staticfinal

Given a DB type, construct the name of the appropriate child class of DatabaseBase. This is designed to replace all of the manual stuff like: $class = 'Database' . ucfirst( strtolower( $dbType ) ); as well as validate against the canonical list of DB types we have

This factory function is mostly useful for when you need to connect to a database other than the MediaWiki default (such as for external auth, an extension, et cetera). Do not use this to connect to the MediaWiki database. Example uses in core:

See Also
LoadBalancer::reallyOpenConnection()
ForeignDBRepo::getMasterDB()
WebInstallerDBConnect::execute()
Since
1.18
Parameters
string$dbTypeA possible DB type
array$pAn array of options to pass to the constructor. Valid options are: host, user, password, dbname, flags, tablePrefix, schema, driver
Exceptions
MWExceptionIf the database driver or extension cannot be found
Returns
DatabaseBase|null DatabaseBase subclass or null
DatabaseBase::fieldExists (   $table,
  $field,
  $fname = __METHOD__ 
)

Determines whether a field exists in a table

Parameters
string$tableTable name
string$fieldFiled to check on that table
string$fnameCalling function name (optional)
Returns
bool Whether $table has filed $field

Implements IDatabase.

DatabaseBase::fieldNamesWithAlias (   $fields)

Gets an array of aliased field names

Parameters
array$fieldsArray( [alias] => field )
Returns
string[] See fieldNameWithAlias()
DatabaseBase::fieldNameWithAlias (   $name,
  $alias = false 
)

Get an aliased field name e.g. fieldName AS newFieldName

Parameters
string$nameField name
string | bool$aliasAlias (optional)
Returns
string SQL name for aliased field. Will not alias a field to its own name
DatabaseBase::fillPrepared (   $preparedQuery,
  $args 
)

For faking prepared SQL statements on DBs that don't support it directly.

Parameters
string$preparedQueryA 'preparable' SQL statement
array$argsArray of Arguments to fill it with
Returns
string Executable SQL
DatabaseBase::fillPreparedArg (   $matches)
protected

preg_callback func for fillPrepared() The arguments should be in $this->preparedArgs and must not be touched while we're doing this.

Parameters
array$matches
Exceptions
DBUnexpectedError
Returns
string
DatabaseBase::freePrepared (   $prepared)
protected

Free a prepared query, generated by prepare().

Parameters
string$prepared
DatabaseBase::freeResult (   $res)

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.

Parameters
mixed$resA SQL result

Implements IDatabase.

DatabaseBase::functionalIndexes ( )

Returns true if this database can use functional indexes

Returns
bool
static DatabaseBase::generalizeSQL (   $sql)
staticprotected

Removes most variables from an SQL query and replaces them with X or N for numbers. It's only slightly flawed. Don't use for anything important.

Parameters
string$sqlA SQL Query
Returns
string
DatabaseBase::getApproximateLagStatus ( )

Get a slave lag estimate for this server

Returns
array ('lag': seconds or false on error, 'since': UNIX timestamp of estimate)
Since
1.27
DatabaseBase::getDBname ( )

Get the current DB name

Returns
string

Implements IDatabase.

DatabaseBase::getDefaultSchemaVars ( )
protected

Get schema variables to use if none have been set via setSchemaVars().

Override this in derived classes to provide variables for tables.sql and SQL patch files.

Returns
array
DatabaseBase::getDelimiter ( )
Returns
string Command delimiter used by this database engine
DatabaseBase::getFlag (   $flag)

Returns a boolean whether the flag $flag is set for this connection

Parameters
int$flagDBO_* constants from Defines.php:
  • DBO_DEBUG: output some debug info (same as debug())
  • DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
  • DBO_TRX: automatically start transactions
  • DBO_PERSISTENT: use persistant database connection
Returns
bool

Implements IDatabase.

DatabaseBase::getInfinity ( )

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.

Returns
string

Implements IDatabase.

DatabaseBase::getLag ( )

Get slave lag. Currently supported only by MySQL.

Note that this function will generate a fatal error on many installations. Most callers should use LoadBalancer::safeGetLag() instead.

Returns
int|bool Database replication lag in seconds or false on error

Implements IDatabase.

DatabaseBase::getLazyMasterHandle ( )
Returns
IDatabase|null
See Also
setLazyMasterHandle()
Since
1.27
DatabaseBase::getLBInfo (   $name = null)

Get properties passed down from the server info array of the load balancer.

Parameters
string$nameThe entry of the info array to get, or null to get the whole array
Returns
array|mixed|null

Implements IDatabase.

DatabaseBase::getLogContext ( array  $extras = [])
protected

Create a log context to pass to wfLogDBError or other logging functions.

Parameters
array$extrasAdditional data to add to context
Returns
array
DatabaseBase::getMasterPos ( )

Get the position of this master

Returns
DBMasterPos|bool False if this is not a master

Implements IDatabase.

DatabaseBase::getProperty (   $name)

General read-only accessor

Parameters
string$name
Returns
string

Implements IDatabase.

DatabaseBase::getReadOnlyReason ( )
protected
Returns
string|bool Reason this DB is read-only or false if it is not
DatabaseBase::getSchemaPath ( )

Return a path to the DBMS-specific schema file, otherwise default to tables.sql

Returns
string
DatabaseBase::getSchemaVars ( )
protected

Get schema variables. If none have been set via setSchemaVars(), then use some defaults from the current object.

Returns
array
DatabaseBase::getScopedLockAndFlush (   $lockKey,
  $fname,
  $timeout 
)

Acquire a named lock, flush any transaction, and return an RAII style unlocker object

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, any transaction will be committed and the lock will be released.

If the lock acquisition failed, then no transaction flush happens, and null is returned.

Parameters
string$lockKeyName of lock to release
string$fnameName of the calling method
int$timeoutAcquisition timeout in seconds
Returns
ScopedCallback|null
Exceptions
DBUnexpectedError
Since
1.27

Implements IDatabase.

DatabaseBase::getSearchEngine ( )

Get search engine class. All subclasses of this need to implement this if they wish to use searching.

Returns
string
DatabaseBase::getServer ( )

Get the server hostname or IP address

Returns
string

Implements IDatabase.

DatabaseBase::getServerInfo ( )

A string describing the current software version, and possibly other details in a user-friendly way. Will be listed on Special:Version, etc. Use getServerVersion() to get machine-friendly information.

Returns
string Version information from the database server

Implements IDatabase.

DatabaseBase::getServerUptime ( )

Determines how long the server has been up STUB

Returns
int

Implements IDatabase.

DatabaseBase::getSessionLagStatus ( )

Get the slave 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 AUTO-COMMIT mode, this still gives an indication of the staleness of subsequent reads.

Returns
array ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
Since
1.27

Implements IDatabase.

DatabaseBase::getSlavePos ( )

Get the replication position of this slave

Returns
DBMasterPos|bool False if this is not a slave.

Implements IDatabase.

DatabaseBase::getTransactionLagStatus ( )

Get the slave lag when the current transaction started

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. This returns null if there is no transaction.

Returns
array|null ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
Since
1.27
DatabaseBase::getTransactionProfiler ( )
protected
DatabaseBase::getUpdateKeysPath ( )

Return a path to the DBMS-specific update key file, otherwise default to update-keys.sql

Returns
string
DatabaseBase::getWikiID ( )
Returns
string

Implements IDatabase.

DatabaseBase::ignoreErrors (   $ignoreErrors = null)
protected

Turns on (false) or off (true) the automatic generation and sending of a "we're sorry, but there has been a database error" page on database errors. Default is on (false). When turned off, the code should use lastErrno() and lastError() to handle the situation as appropriate.

Do not use this function outside of the Database classes.

Parameters
null | bool$ignoreErrors
Returns
bool The previous value of the flag.
DatabaseBase::implicitGroupby ( )

Returns true if this database does an implicit sort when doing GROUP BY

Returns
bool

Implements IDatabase.

DatabaseBase::implicitOrderby ( )

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

Returns
bool

Implements IDatabase.

DatabaseBase::indexExists (   $table,
  $index,
  $fname = __METHOD__ 
)

Determines whether an index exists Usually throws a DBQueryError on failure If errors are explicitly ignored, returns NULL on failure

Parameters
string$table
string$index
string$fname
Returns
bool|null

Implements IDatabase.

DatabaseBase::indexInfo (   $table,
  $index,
  $fname = __METHOD__ 
)
abstract

Get information about an index into an object

Parameters
string$tableTable name
string$indexIndex name
string$fnameCalling function name
Returns
mixed Database-specific index description class or false if the index does not exist
DatabaseBase::indexName (   $index)
protected

Get the name of an index in a given table.

Parameters
string$index
Returns
string
DatabaseBase::indexUnique (   $table,
  $index 
)

Determines if a given index is unique

Parameters
string$table
string$index
Returns
bool

Implements IDatabase.

DatabaseBase::insert (   $table,
  $a,
  $fname = __METHOD__,
  $options = [] 
)

INSERT wrapper, inserts an array into a table.

$a may be either:

  • A single associative array. The array keys are the field names, and the values are the values to insert. The values are treated as data and will be quoted appropriately. If NULL is inserted, this will be converted to a database NULL.
  • An array with numeric keys, holding a list of associative arrays. This causes a multi-row INSERT on DBMSs that support it. The keys in each subarray must be identical to each other, and in the same order.

Usually throws a DBQueryError on failure. If errors are explicitly ignored, returns success.

$options is an array of options, with boolean options encoded as values with numeric keys, in the same style as $options in IDatabase::select(). Supported options are:

  • IGNORE: Boolean: if present, duplicate key errors are ignored, and any rows which cause duplicate key errors are not inserted. It's possible to determine how many rows were successfully inserted using IDatabase::affectedRows().
Parameters
string$tableTable name. This will be passed through DatabaseBase::tableName().
array$aArray of rows to insert
string$fnameCalling function name (use METHOD) for logs/profiling
array$optionsArray of options
Returns
bool

Implements IDatabase.

DatabaseBase::insertSelect (   $destTable,
  $srcTable,
  $varMap,
  $conds,
  $fname = __METHOD__,
  $insertOptions = [],
  $selectOptions = [] 
)

INSERT SELECT wrapper. Takes data from a SELECT query and inserts it into another table.

Parameters
string$destTableThe table name to insert into
string | array$srcTableMay be either a table name, or an array of table names to include in a join.
array$varMapMust be an associative array of the form array( 'dest1' => 'source1', ...). Source items may be literals rather than field names, but strings should be quoted with IDatabase::addQuotes()
array$condsCondition array. See $conds in IDatabase::select() for the details of the format of condition arrays. May be "*" to copy the whole table.
string$fnameThe function name of the caller, from METHOD
array$insertOptionsOptions for the INSERT part of the query, see IDatabase::insert() for details.
array$selectOptionsOptions for the SELECT part of the query, see IDatabase::select() for details.
Returns
ResultWrapper

Implements IDatabase.

DatabaseBase::isOpen ( )

Is a connection to the database open?

Returns
bool

Implements IDatabase.

DatabaseBase::isQuotedIdentifier (   $name)

Returns if the given identifier looks quoted or not according to the database convention for quoting identifiers .

Note
Do not use this to determine if untrusted input is safe. A malicious user can trick this function.
Parameters
string$name
Returns
bool
DatabaseBase::isReadOnly ( )
Returns
bool Whether this DB is read-only
Since
1.27

Implements IDatabase.

DatabaseBase::isTransactableQuery (   $sql)
protected

Determine whether a SQL statement is sensitive to isolation level. A SQL statement is considered transactable if its result could vary depending on the transaction isolation level. Operational commands such as 'SET' and 'SHOW' are not considered to be transactable.

Parameters
string$sql
Returns
bool
DatabaseBase::isView (   $name)

Differentiates between a TABLE and a VIEW

Parameters
string$nameName of the database-structure to test.
Exceptions
MWException
Returns
bool
Since
1.22
DatabaseBase::isWriteQuery (   $sql)
protected

Determine whether a query writes to the DB. Should return true if unsure.

Parameters
string$sql
Returns
bool
DatabaseBase::lastDoneWrites ( )

Returns the last time the connection may have been used for write queries. Should return a timestamp if unsure.

Returns
int|float UNIX timestamp or false
Since
1.24

Implements IDatabase.

DatabaseBase::lastQuery ( )

Return the last query that went through IDatabase::query()

Returns
string

Implements IDatabase.

DatabaseBase::limitResult (   $sql,
  $limit,
  $offset = false 
)

Construct a LIMIT query with optional offset. This is used for query pages. 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.

The version provided by default works in MySQL and SQLite. It will very likely need to be overridden for most other DBMSes.

Parameters
string$sqlSQL query we will append the limit too
int$limitThe SQL limit
int | bool$offsetThe SQL offset (default false)
Exceptions
DBUnexpectedError
Returns
string
DatabaseBase::listTables (   $prefix = null,
  $fname = __METHOD__ 
)

List all tables on the database

Parameters
string$prefixOnly show tables with this prefix, e.g. mw_
string$fnameCalling function name
Exceptions
MWException
Returns
array

Implements IDatabase.

DatabaseBase::listViews (   $prefix = null,
  $fname = __METHOD__ 
)

Lists all the VIEWs in the database

For caching purposes the list of all views should be stored in $this->allViews. The process cache can be cleared with clearViewsCache()

Parameters
string$prefixOnly show VIEWs with this prefix, eg. unit_test_
string$fnameName of calling function
Exceptions
MWException
Returns
array
Since
1.22
DatabaseBase::lock (   $lockName,
  $method,
  $timeout = 5 
)

Acquire a named lock

Named locks are not related to transactions

Parameters
string$lockNameName of lock to aquire
string$methodName of the calling method
int$timeoutAcquisition timeout in seconds
Returns
bool

Implements IDatabase.

DatabaseBase::lockIsFree (   $lockName,
  $method 
)

Check to see if a named lock is available (non-blocking)

Parameters
string$lockNameName of lock to poll
string$methodName of method calling us
Returns
bool
Since
1.20

Implements IDatabase.

DatabaseBase::lockTables (   $read,
  $write,
  $method,
  $lowPriority = true 
)

Lock specific tables

Parameters
array$readArray of tables to lock for read access
array$writeArray of tables to lock for write access
string$methodName of caller
bool$lowPriorityWhether to indicate writes to be LOW PRIORITY
Returns
bool
DatabaseBase::lowPriorityOption ( )

A string to insert into queries to show that they're low-priority, like MySQL's LOW_PRIORITY. If no such feature exists, return an empty string and nothing bad should happen.

Returns
string Returns the text of the low priority option if it is supported, or a blank string otherwise
DatabaseBase::makeGroupByWithHaving (   $options)

Returns an optional GROUP BY with an optional HAVING

Parameters
array$optionsAssociative array of options
Returns
string
See Also
DatabaseBase::select()
Since
1.21
DatabaseBase::makeInsertOptions (   $options)
protected

Helper for DatabaseBase::insert().

Parameters
array$options
Returns
string
DatabaseBase::makeList (   $a,
  $mode = LIST_COMMA 
)

Makes an encoded list of strings from an array

Parameters
array$aContaining the data
int$modeConstant
  • LIST_COMMA: Comma separated, no field names
  • LIST_AND: ANDed WHERE clause (without the WHERE). See the documentation for $conds in IDatabase::select().
  • LIST_OR: ORed WHERE clause (without the WHERE)
  • LIST_SET: Comma separated with field names, like a SET clause
  • LIST_NAMES: Comma separated field names
Exceptions
MWException|DBUnexpectedError
Returns
string

Implements IDatabase.

DatabaseBase::makeOrderBy (   $options)

Returns an optional ORDER BY

Parameters
array$optionsAssociative array of options
Returns
string
See Also
DatabaseBase::select()
Since
1.21
DatabaseBase::makeSelectOptions (   $options)

Returns an optional USE INDEX clause to go after the table, and a string to go at the end of the query.

Parameters
array$optionsAssociative array of options to be turned into an SQL query, valid keys are listed in the function.
Returns
array
See Also
DatabaseBase::select()
DatabaseBase::makeUpdateOptions (   $options)
protected

Make UPDATE options for the DatabaseBase::update function

Parameters
array$optionsThe options passed to DatabaseBase::update
Returns
string
DatabaseBase::makeUpdateOptionsArray (   $options)
protected

Make UPDATE options array for DatabaseBase::makeUpdateOptions

Parameters
array$options
Returns
array
DatabaseBase::makeWhereFrom2d (   $data,
  $baseKey,
  $subKey 
)

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.

Parameters
array$dataOrganized as 2-d array(baseKeyVal => array(subKeyVal => [ignored], ...), ...)
string$baseKeyField name to match the base-level keys to (eg 'pl_namespace')
string$subKeyField name to match the sub-level keys to (eg 'pl_title')
Returns
string|bool SQL fragment, or false if no items in array

Implements IDatabase.

DatabaseBase::masterPosWait ( DBMasterPos  $pos,
  $timeout 
)

Wait for the slave to catch up to a given master position

Parameters
DBMasterPos$pos
int$timeoutThe maximum number of seconds to wait for synchronisation
Returns
int|null Zero if the slave 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

Implements IDatabase.

DatabaseBase::maxListLen ( )

Return the maximum number of items allowed in a list, or 0 for unlimited.

Returns
int

Implements IDatabase.

DatabaseBase::namedLocksEnqueue ( )

Check to see if a named lock used by lock() use blocking queues

Returns
bool
Since
1.26

Implements IDatabase.

DatabaseBase::nativeReplace (   $table,
  $rows,
  $fname 
)
protected

REPLACE query wrapper for MySQL and SQLite, which have a native REPLACE statement.

Parameters
string$tableTable name
array | string$rowsRow(s) to insert
string$fnameCaller function name
Returns
ResultWrapper
DatabaseBase::nextSequenceValue (   $seqName)

Returns an appropriately quoted sequence value for inserting a new row. MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL subclass will return an integer, and save the value for insertId()

Any implementation of this function should not involve reusing sequence numbers created for rolled-back transactions. See http://bugs.mysql.com/bug.php?id=30767 for details.

Parameters
string$seqName
Returns
null|int

Implements IDatabase.

DatabaseBase::onTransactionIdle (   $callback)
final

Run an anonymous function as soon as there is no transaction pending. If there is a transaction and it is rolled back, then the callback is cancelled. Queries in the function will run in AUTO-COMMIT 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 cause deadlocks if locks are held too long.

Updates will execute in the order they were enqueued.

Parameters
callable$callback
Since
1.20

Implements IDatabase.

DatabaseBase::onTransactionPreCommitOrIdle (   $callback)
final

Run an anonymous function 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. Callbacks must not start nor commit any transactions.

This is useful for updates that easily cause deadlocks if locks are held too long but where atomicity is strongly desired for these updates and some related updates.

Updates will execute in the order they were enqueued.

Parameters
callable$callback
Since
1.22

Implements IDatabase.

DatabaseBase::patchPath (   $patch)

Get the full path of a patch file. Originally based on archive() from updaters.inc. Keep in mind this always returns a patch, as it fails back to MySQL if no DB-specific patch can be found

Parameters
string$patchThe name of the patch, like patch-something.sql
Returns
string Full path to patch file
DatabaseBase::pendingWriteCallers ( )

Get the list of method names that did write queries for this transaction

Returns
array
Since
1.27

Implements IDatabase.

DatabaseBase::pendingWriteQueryDuration ( )

Get the time spend running write queries for this transaction

High times could be due to scanning, updates, locking, and such

Returns
float|bool Returns false if not transaction is active
Since
1.26

Implements IDatabase.

DatabaseBase::ping ( )

Ping the server and try to reconnect if it there is no connection

Returns
bool Success or failure

Implements IDatabase.

DatabaseBase::prepare (   $sql,
  $func = 'DatabaseBase::prepare' 
)
protected

Intended to be compatible with the PEAR::DB wrapper functions. http://pear.php.net/manual/en/package.database.db.intro-execute.php

? = scalar value, quoted as necessary ! = raw SQL bit (a function for instance) & = filename; reads the file and inserts as a blob (we don't use this though...)

Parameters
string$sql
string$func
Returns
array
DatabaseBase::query (   $sql,
  $fname = __METHOD__,
  $tempIgnore = false 
)

Run an SQL query and return the result. Normally throws a DBQueryError on failure. If errors are ignored, returns false instead.

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.

Parameters
string$sqlSQL query
string$fnameName of the calling function, for profiling/SHOW PROCESSLIST comment (you can use METHOD or add some extra info)
bool$tempIgnoreWhether to avoid throwing an exception on errors... maybe best to catch the exception instead?
Exceptions
MWException
Returns
bool|ResultWrapper True for a successful write query, ResultWrapper object for a successful read query, or false on failure if $tempIgnore set

Implements IDatabase.

DatabaseBase::realTimestamps ( )

Returns true if this database uses timestamps rather than integers

Returns
bool
DatabaseBase::replace (   $table,
  $uniqueIndexes,
  $rows,
  $fname = __METHOD__ 
)

REPLACE query wrapper.

REPLACE is a very handy MySQL extension, which functions like an INSERT except that when there is a duplicate key error, the old row is deleted and the new row is inserted in its place.

We simulate this with standard SQL with a DELETE followed by INSERT. To perform the delete, we need to know what the unique indexes are so that we know how to find the conflicting rows.

It may be more efficient to leave off unique indexes which are unlikely to collide. However if you do this, you run the risk of encountering errors which wouldn't have occurred in MySQL.

Parameters
string$tableThe table to replace the row(s) in.
array$uniqueIndexesIs an array of indexes. Each element may be either a field name or an array of field names
array$rowsCan be either a single row to insert, or multiple rows, in the same format as for IDatabase::insert()
string$fnameCalling function name (use METHOD) for logs/profiling

Implements IDatabase.

DatabaseBase::replaceVars (   $ins)
protected

Database independent variable replacement. Replaces a set of variables in an SQL statement with their contents as given by $this->getSchemaVars().

Supports '{$var}' {$var} and / *$var* / (without the spaces) style variables.

  • '{$var}' should be used for text and is passed through the database's addQuotes method.
  • {$var} should be used for identifiers (e.g. table and database names). It is passed through the database's addIdentifierQuotes method which can be overridden if the database uses something other than backticks.
  • / *_* / or / *$wgDBprefix* / passes the name that follows through the database's tableName method.
  • / i / passes the name that follows through the database's indexName method.
  • In all other cases, / *$var* / is left unencoded. Except for table options, its use should be avoided. In 1.24 and older, string encoding was applied.
Parameters
string$insSQL statement to replace variables in
Returns
string The new SQL statement with variables replaced
DatabaseBase::reportConnectionError (   $error = 'Unknown error')
Parameters
string$errorFallback error message, used if none is given by DB
Exceptions
DBConnectionError

Implements IDatabase.

DatabaseBase::reportQueryError (   $error,
  $errno,
  $sql,
  $fname,
  $tempIgnore = false 
)

Report a query error. Log the error, and if neither the object ignore flag nor the $tempIgnore flag is set, throw a DBQueryError.

Parameters
string$error
int$errno
string$sql
string$fname
bool$tempIgnore
Exceptions
DBQueryError

Implements IDatabase.

DatabaseBase::restoreErrorHandler ( )
protected
Returns
bool|string
DatabaseBase::resultObject (   $result)
protected

Take the result from a query, and wrap it in a ResultWrapper if necessary. Boolean values are passed through as is, to indicate success of write queries or failure.

Once upon a time, DatabaseBase::query() returned a bare MySQL result resource, and it was necessary to call this function to convert it to a wrapper. Nowadays, raw database objects are never exposed to external callers, so this is unnecessary in external code.

Parameters
bool | ResultWrapper | resource | object$result
Returns
bool|ResultWrapper
DatabaseBase::rollback (   $fname = __METHOD__,
  $flush = '' 
)
final

Rollback a transaction previously started using begin(). If no transaction is in progress, a warning is issued.

No-op on non-transactional databases.

Parameters
string$fname
string$flushFlush flag, set to 'flush' 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.
Exceptions
DBUnexpectedError
Since
1.23 Added $flush parameter

Implements IDatabase.

DatabaseBase::runOnTransactionIdleCallbacks ( )
protected

Actually any "on transaction idle" callbacks.

Since
1.20
DatabaseBase::runOnTransactionPreCommitCallbacks ( )
protected

Actually any "on transaction pre-commit" callbacks.

Since
1.22
DatabaseBase::searchableIPs ( )

Returns true if this database can do a native search on IP columns e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';

Returns
bool
DatabaseBase::select (   $table,
  $vars,
  $conds = '',
  $fname = __METHOD__,
  $options = [],
  $join_conds = [] 
)

Execute a SELECT query constructed using the various parameters provided. See below for full details of the parameters.

Parameters
string | array$tableTable name
string | array$varsField names
string | array$condsConditions
string$fnameCaller function name
array$optionsQuery options
array$join_condsJoin conditions
string | array$tableMay 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:

array( '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).

All of the table names given here are automatically run through DatabaseBase::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.

Parameters
string | array$varsMay 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:

array( '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.

Parameters
string | array$condsMay 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:

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()

Parameters
string | array$optionsOptional: Array of query options. Boolean options are specified by including them in the array as a string value with a numeric key, for example:

array( '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 in MediaWiki 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.
  • FOR UPDATE: Boolean: lock the returned rows so that they can't be changed until the next COMMIT.
  • 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.
  • 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:

  • LOCK IN SHARE MODE
  • STRAIGHT_JOIN
  • HIGH_PRIORITY
  • SQL_BIG_RESULT
  • SQL_BUFFER_RESULT
  • SQL_SMALL_RESULT
  • SQL_CALC_FOUND_ROWS
  • SQL_CACHE
  • SQL_NO_CACHE
Parameters
string | array$join_condsOptional 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:

array( 'page' => array( 'LEFT JOIN', 'page_latest=rev_id' ) )

Returns
ResultWrapper|bool If the query returned no rows, a ResultWrapper with no rows in it will be returned. If there was a query error, a DBQueryError exception will be thrown, except if the "ignore errors" option was set, in which case false will be returned.

Implements IDatabase.

DatabaseBase::selectDB (   $db)

Change the current database

Parameters
string$db
Returns
bool Success or failure

Implements IDatabase.

DatabaseBase::selectField (   $table,
  $var,
  $cond = '',
  $fname = __METHOD__,
  $options = [] 
)

A SELECT wrapper which returns a single field from a single result row.

Usually throws a DBQueryError on failure. If errors are explicitly ignored, returns false on failure.

If no result rows are returned from the query, false is returned.

Parameters
string | array$tableTable name. See IDatabase::select() for details.
string$varThe field name to select. This must be a valid SQL fragment: do not use unvalidated user input.
string | array$condThe condition array. See IDatabase::select() for details.
string$fnameThe function name of the caller.
string | array$optionsThe query options. See IDatabase::select() for details.
Returns
bool|mixed The value from the field, or false on failure.

Implements IDatabase.

DatabaseBase::selectRow (   $table,
  $vars,
  $conds,
  $fname = __METHOD__,
  $options = [],
  $join_conds = [] 
)

Single row SELECT wrapper. Equivalent to IDatabase::select(), except that a single row object is returned. If the query returns no rows, false is returned.

Parameters
string | array$tableTable name
string | array$varsField names
array$condsConditions
string$fnameCaller function name
string | array$optionsQuery options
array | string$join_condsJoin conditions
Returns
stdClass|bool

Implements IDatabase.

DatabaseBase::selectRowCount (   $tables,
  $vars = '*',
  $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 $join_conds parameter
Parameters
array | string$tablesTable names
string$varsUnused
array | string$condsFilters on the table
string$fnameFunction name for profiling
array$optionsOptions for select
array$join_condsJoin conditions (since 1.27)
Returns
int Row count

Implements IDatabase.

DatabaseBase::selectSQLText (   $table,
  $vars,
  $conds = '',
  $fname = __METHOD__,
  $options = [],
  $join_conds = [] 
)

The equivalent of IDatabase::select() except that the constructed SQL is returned, instead of being immediately executed. This can be useful for doing UNION queries, where the SQL text of each query is needed. In general, however, callers outside of Database classes should just use select().

Parameters
string | array$tableTable name
string | array$varsField names
string | array$condsConditions
string$fnameCaller function name
string | array$optionsQuery options
string | array$join_condsJoin conditions
Returns
string SQL query string.
See Also
IDatabase::select()

Implements IDatabase.

DatabaseBase::setBigSelects (   $value = true)

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.

Parameters
bool | string$valueTrue for allow, false for deny, or "default" to restore the initial value

Implements IDatabase.

DatabaseBase::setFileHandle (   $fh)

Set the filehandle to copy write statements to.

Parameters
resource$fhFile handle
DatabaseBase::setFlag (   $flag)

Set a flag for this connection

Parameters
int$flagDBO_* constants from Defines.php:
  • DBO_DEBUG: output some debug info (same as debug())
  • DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
  • DBO_TRX: automatically start transactions
  • DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode and removes it in command line mode
  • DBO_PERSISTENT: use persistant database connection

Implements IDatabase.

DatabaseBase::setLazyMasterHandle ( IDatabase  $conn)

Set a lazy-connecting DB handle to the master DB (for replication status purposes)

Parameters
IDatabase$conn
Since
1.27
DatabaseBase::setLBInfo (   $name,
  $value = null 
)

Set the LB info array, or a member of it. If called with one parameter, the LB info array is set to that parameter. If it is called with two parameters, the member with the given name is set to the given value.

Parameters
string$name
array$value

Implements IDatabase.

DatabaseBase::setSchemaVars (   $vars)

Set variables to be used in sourceFile/sourceStream, in preference to the ones in $GLOBALS. If an array is set here, $GLOBALS will not be used at all. If it's set to false, $GLOBALS will be used.

Parameters
bool | array$varsMapping variable name to value.

Implements IDatabase.

DatabaseBase::setSessionOptions ( array  $options)

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.

Parameters
array$options
Returns
void

Implements IDatabase.

DatabaseBase::setTransactionProfiler ( TransactionProfiler  $profiler)
Parameters
TransactionProfiler$profiler
Since
1.27
DatabaseBase::sourceFile (   $filename,
  $lineCallback = false,
  $resultCallback = false,
  $fname = false,
  $inputCallback = false 
)

Read and execute SQL commands from a file.

Returns true on success, error string or exception on failure (depending on object's error ignore settings).

Parameters
string$filenameFile name to open
bool | callable$lineCallbackOptional function called before reading each line
bool | callable$resultCallbackOptional function called for each MySQL result
bool | string$fnameCalling function name or false if name should be generated dynamically using $filename
bool | callable$inputCallbackOptional function called for each complete line sent
Exceptions
Exception|MWException
Returns
bool|string
DatabaseBase::sourceStream (   $fp,
  $lineCallback = false,
  $resultCallback = false,
  $fname = __METHOD__,
  $inputCallback = false 
)

Read and execute commands from an open file handle.

Returns true on success, error string or exception on failure (depending on object's error ignore settings).

Parameters
resource$fpFile handle
bool | callable$lineCallbackOptional function called before reading each query
bool | callable$resultCallbackOptional function called for each MySQL result
string$fnameCalling function name
bool | callable$inputCallbackOptional function called for each complete query sent
Returns
bool|string
DatabaseBase::startAtomic (   $fname = __METHOD__)
final

Begin an atomic section of statements

If a transaction has been started already, just keep track of the given section name to make sure the transaction is not committed pre-maturely. This function can be used in layers (with sub-sections), so use a stack to keep track of the different atomic sections. If there is no transaction, start one implicitly.

The goal of this function is to create an atomic section of SQL queries without having to start a new transaction if it already exists.

Atomic sections are more strict than transactions. With transactions, attempting to begin a new transaction when one is already running results in MediaWiki issuing a brief warning and doing an implicit commit. All atomic levels must be explicitly closed using IDatabase::endAtomic(), and any database transactions cannot be began or committed until all atomic levels are closed. There is no such thing as implicitly opening or closing an atomic section.

Since
1.23
Parameters
string$fname
Exceptions
DBError

Implements IDatabase.

DatabaseBase::streamStatementEnd ( $sql,
$newLine 
)

Called by sourceStream() to check if we've reached a statement end

Parameters
string$sqlSQL assembled so far
string$newLineNew line about to be added to $sql
Returns
bool Whether $newLine contains end of the statement
DatabaseBase::strencode (   $s)
abstract

Wrapper for addslashes()

Parameters
string$sString to be slashed.
Returns
string Slashed string.
DatabaseBase::strictIPs ( )

Returns true if this database is strict about what can be put into an IP field. Specifically, it uses a NULL value instead of an empty string.

Returns
bool
DatabaseBase::strreplace (   $orig,
  $old,
  $new 
)

Returns a comand for str_replace function in SQL query. Uses REPLACE() in MySQL

Parameters
string$origColumn to modify
string$oldColumn to seek
string$newColumn to replace with
Returns
string

Implements IDatabase.

DatabaseBase::tableExists (   $table,
  $fname = __METHOD__ 
)

Query whether a given table exists

Parameters
string$table
string$fname
Returns
bool

Implements IDatabase.

DatabaseBase::tableName (   $name,
  $format = 'quoted' 
)

Format a table name ready for use in constructing an SQL query

This does two important things: it quotes the table names to clean them up, and it adds a table prefix if only given a table name with no quotes.

All functions of this object which require a table name call this function themselves. Pass the canonical name to such functions. This is only needed when calling query() directly.

Note
This function does not sanitize user input. It is not safe to use this function to escape user input.
Parameters
string$nameDatabase table name
string$formatOne of: quoted - Automatically pass the table name through addIdentifierQuotes() so that it can be used in a query. raw - Do not add identifier quotes to the table name
Returns
string Full database name
DatabaseBase::tableNames ( )

Fetch a number of table names into an array This is handy when you need to construct SQL for joins

Example: extract( $dbr->tableNames( 'user', 'watchlist' ) ); $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user WHERE wl_user=user_id AND wl_user=$nameWithQuotes";

Returns
array
DatabaseBase::tableNamesN ( )

Fetch a number of table names into an zero-indexed numerical array This is handy when you need to construct SQL for joins

Example: list( $user, $watchlist ) = $dbr->tableNamesN( 'user', 'watchlist' ); $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user WHERE wl_user=user_id AND wl_user=$nameWithQuotes";

Returns
array
DatabaseBase::tableNamesWithAlias (   $tables)

Gets an array of aliased table names

Parameters
array$tablesArray( [alias] => table )
Returns
string[] See tableNameWithAlias()
DatabaseBase::tableNamesWithUseIndexOrJOIN (   $tables,
  $use_index = [],
  $join_conds = [] 
)
protected

Get the aliased table name clause for a FROM clause which might have a JOIN and/or USE INDEX clause

Parameters
array$tables( [alias] => table )
array$use_indexSame as for select()
array$join_condsSame as for select()
Returns
string
DatabaseBase::tableNameWithAlias (   $name,
  $alias = false 
)

Get an aliased table name e.g. tableName AS newTableName

Parameters
string$nameTable name, see tableName()
string | bool$aliasAlias (optional)
Returns
string SQL name for aliased table. Will not alias a table to its own name
DatabaseBase::tablePrefix (   $prefix = null)

Get/set the table prefix.

Parameters
string$prefixThe table prefix to set, or omitted to leave it unchanged.
Returns
string The previous table prefix.

Implements IDatabase.

DatabaseBase::textFieldSize (   $table,
  $field 
)

Returns the size of a text field, or -1 for "unlimited"

Parameters
string$table
string$field
Returns
int
DatabaseBase::timestamp (   $ts = 0)

Convert a timestamp in one of the formats accepted by wfTimestamp() 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.

Parameters
string | int$ts
Returns
string

Implements IDatabase.

DatabaseBase::timestampOrNull (   $ts = null)

Convert a timestamp in one of the formats accepted by wfTimestamp() 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.

Parameters
string | int$ts
Returns
string

Implements IDatabase.

DatabaseBase::trxLevel ( )

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.

Returns
int The previous value

Implements IDatabase.

DatabaseBase::trxTimestamp ( )

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.

Returns
float|null Returns null if there is not active transaction
Since
1.25

Implements IDatabase.

DatabaseBase::unionQueries (   $sqls,
  $all 
)

Construct a UNION query This is used for providing overload point for other DB abstractions not compatible with the MySQL syntax.

Parameters
array$sqlsSQL statements to combine
bool$allUse UNION ALL
Returns
string SQL fragment

Implements IDatabase.

DatabaseBase::unionSupportsOrderAndLimit ( )

Returns true if current database backend supports ORDER BY or LIMIT for separate subqueries within the UNION construct.

Returns
bool

Implements IDatabase.

DatabaseBase::unlock (   $lockName,
  $method 
)

Release a lock

Named locks are not related to transactions

Parameters
string$lockNameName of lock to release
string$methodName of the calling method
Returns
int Returns 1 if the lock was released, 0 if the lock was not established by this thread (in which case the lock is not released), and NULL if the named lock did not exist

Implements IDatabase.

DatabaseBase::unlockTables (   $method)

Unlock specific tables

Parameters
string$methodThe caller
Returns
bool
DatabaseBase::update (   $table,
  $values,
  $conds,
  $fname = __METHOD__,
  $options = [] 
)

UPDATE wrapper. Takes a condition array and a SET array.

Parameters
string$tableName of the table to UPDATE. This will be passed through DatabaseBase::tableName().
array$valuesAn array of values to SET. For each array element, the key gives the field name, and the value gives the data to set that field to. The data will be quoted by IDatabase::addQuotes().
array$condsAn array of conditions (WHERE). See IDatabase::select() for the details of the format of condition arrays. Use '*' to update all rows.
string$fnameThe function name of the caller (from METHOD), for logging and profiling.
array$optionsAn array of UPDATE options, can be:
  • IGNORE: Ignore unique key conflicts
  • LOW_PRIORITY: MySQL-specific, see MySQL manual.
Returns
bool

Implements IDatabase.

DatabaseBase::upsert (   $table,
array  $rows,
array  $uniqueIndexes,
array  $set,
  $fname = __METHOD__ 
)

INSERT ON DUPLICATE KEY UPDATE wrapper, upserts an array into a table.

This updates any conflicting rows (according to the unique indexes) using the provided SET clause and inserts any remaining (non-conflicted) rows.

$rows may be either:

  • A single associative array. The array keys are the field names, and the values are the values to insert. The values are treated as data and will be quoted appropriately. If NULL is inserted, this will be converted to a database NULL.
  • An array with numeric keys, holding a list of associative arrays. This causes a multi-row INSERT on DBMSs that support it. The keys in each subarray must be identical to each other, and in the same order.

It may be more efficient to leave off unique indexes which are unlikely to collide. However if you do this, you run the risk of encountering errors which wouldn't have occurred in MySQL.

Usually throws a DBQueryError on failure. If errors are explicitly ignored, returns success.

Since
1.22
Parameters
string$tableTable name. This will be passed through DatabaseBase::tableName().
array$rowsA single row or list of rows to insert
array$uniqueIndexesList of single field names or field name tuples
array$setAn array of values to SET. For each array element, the key gives the field name, and the value gives the data to set that field to. The data will be quoted by IDatabase::addQuotes().
string$fnameCalling function name (use METHOD) for logs/profiling
Exceptions
Exception
Returns
bool

Implements IDatabase.

DatabaseBase::useIndexClause (   $index)

USE INDEX clause. Unlikely to be useful for anything but MySQL. This is only needed because a) MySQL must be as efficient as possible due to its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about which index to pick. Anyway, other databases might have different indexes on a given table. So don't bother overriding this unless you're MySQL.

Parameters
string$index
Returns
string
DatabaseBase::wasConnectionError (   $errno)

Determines if the given query error was a connection drop STUB

Parameters
integer | string$errno
Returns
bool
DatabaseBase::wasDeadlock ( )

Determines if the last failure was due to a deadlock STUB

Returns
bool

Implements IDatabase.

DatabaseBase::wasErrorReissuable ( )

Determines if the last query error was something that should be dealt with by pinging the connection and reissuing the query. STUB

Returns
bool

Implements IDatabase.

DatabaseBase::wasLockTimeout ( )

Determines if the last failure was due to a lock timeout STUB

Returns
bool

Implements IDatabase.

DatabaseBase::wasReadOnlyError ( )

Determines if the last failure was due to the database being read-only. STUB

Returns
bool

Implements IDatabase.

DatabaseBase::writesOrCallbacksPending ( )

Returns true if there is a transaction open with possible write queries or transaction pre-commit/idle callbacks waiting on it to finish.

Returns
bool

Implements IDatabase.

DatabaseBase::writesPending ( )
Returns
bool Whether there is a transaction open with possible write queries
Since
1.27

Implements IDatabase.

Member Data Documentation

const DatabaseBase::DEADLOCK_DELAY_MAX = 1500000

Maximum time to wait before retry

const DatabaseBase::DEADLOCK_DELAY_MIN = 500000

Minimum time to wait before retry, in microseconds

const DatabaseBase::DEADLOCK_TRIES = 4

Number of times to re-try an operation in case of deadlock


The documentation for this class was generated from the following file: