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IDatabase Interface Reference
Inheritance diagram for IDatabase:

Public Member Functions

 getServerInfo ()
 
 bufferResults ($buffer=null)
 
 trxLevel ()
 
 trxTimestamp ()
 
 tablePrefix ($prefix=null)
 
 dbSchema ($schema=null)
 
 getLBInfo ($name=null)
 
 setLBInfo ($name, $value=null)
 
 implicitGroupby ()
 
 implicitOrderby ()
 
 lastQuery ()
 
 doneWrites ()
 
 lastDoneWrites ()
 
 writesPending ()
 
 writesOrCallbacksPending ()
 
 pendingWriteQueryDuration ()
 
 pendingWriteCallers ()
 
 isOpen ()
 
 setFlag ($flag)
 
 clearFlag ($flag)
 
 getFlag ($flag)
 
 getProperty ($name)
 
 getWikiID ()
 
 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 ()
 
 close ()
 
 reportConnectionError ($error= 'Unknown error')
 
 query ($sql, $fname=__METHOD__, $tempIgnore=false)
 
 reportQueryError ($error, $errno, $sql, $fname, $tempIgnore=false)
 
 freeResult ($res)
 
 selectField ($table, $var, $cond= '', $fname=__METHOD__, $options=[])
 
 selectFieldValues ($table, $var, $cond= '', $fname=__METHOD__, $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)
 
 bitNot ($field)
 
 bitAnd ($fieldLeft, $fieldRight)
 
 bitOr ($fieldLeft, $fieldRight)
 
 buildConcat ($stringList)
 
 buildGroupConcatField ($delim, $table, $field, $conds= '', $join_conds=[])
 
 selectDB ($db)
 
 getDBname ()
 
 getServer ()
 
 addQuotes ($s)
 
 buildLike ()
 
 anyChar ()
 
 anyString ()
 
 nextSequenceValue ($seqName)
 
 replace ($table, $uniqueIndexes, $rows, $fname=__METHOD__)
 
 upsert ($table, array $rows, array $uniqueIndexes, array $set, $fname=__METHOD__)
 
 deleteJoin ($delTable, $joinTable, $delVar, $joinVar, $conds, $fname=__METHOD__)
 
 delete ($table, $conds, $fname=__METHOD__)
 
 insertSelect ($destTable, $srcTable, $varMap, $conds, $fname=__METHOD__, $insertOptions=[], $selectOptions=[])
 
 unionSupportsOrderAndLimit ()
 
 unionQueries ($sqls, $all)
 
 conditional ($cond, $trueVal, $falseVal)
 
 strreplace ($orig, $old, $new)
 
 getServerUptime ()
 
 wasDeadlock ()
 
 wasLockTimeout ()
 
 wasErrorReissuable ()
 
 wasReadOnlyError ()
 
 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= '')
 
 listTables ($prefix=null, $fname=__METHOD__)
 
 timestamp ($ts=0)
 
 timestampOrNull ($ts=null)
 
 ping ()
 
 getLag ()
 
 getSessionLagStatus ()
 
 maxListLen ()
 
 encodeBlob ($b)
 
 decodeBlob ($b)
 
 setSessionOptions (array $options)
 
 setSchemaVars ($vars)
 
 lockIsFree ($lockName, $method)
 
 lock ($lockName, $method, $timeout=5)
 
 unlock ($lockName, $method)
 
 getScopedLockAndFlush ($lockKey, $fname, $timeout)
 
 namedLocksEnqueue ()
 
 getInfinity ()
 
 encodeExpiry ($expiry)
 
 decodeExpiry ($expiry, $format=TS_MW)
 
 setBigSelects ($value=true)
 
 isReadOnly ()
 

Detailed Description

Basic database interface for live and lazy-loaded DB handles

Todo:
: loosen up DB classes from MWException
Note
: IDatabase and DBConnRef should be updated to reflect any changes

Member Function Documentation

IDatabase::addQuotes (   $s)

Adds quotes and backslashes.

Parameters
string | Blob$s
Returns
string

Implemented in DatabaseBase, DatabasePostgres, DatabaseOracle, DatabaseMssql, DatabaseSqlite, and DBConnRef.

IDatabase::affectedRows ( )
IDatabase::anyChar ( )

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

Returns
LikeMatch

Implemented in DatabaseBase, and DBConnRef.

IDatabase::anyString ( )

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

Returns
LikeMatch

Implemented in DatabaseBase, and DBConnRef.

IDatabase::begin (   $fname = __METHOD__)

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

Implemented in DatabaseBase, and DBConnRef.

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

Implemented in DatabaseBase, DatabaseOracle, and DBConnRef.

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

Implemented in DatabaseBase, DatabaseOracle, and DBConnRef.

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

Implemented in DatabaseBase, DatabaseOracle, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseMssql, DatabaseSqlite, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseOracle, DatabaseMssql, DatabaseSqlite, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMssql, DatabaseSqlite, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DBConnRef, and FakeDatabase.

IDatabase::close ( )

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

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::commit (   $fname = __METHOD__,
  $flush = '' 
)

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::dataSeek (   $res,
  $row 
)

Change the position of the cursor in a result object

See Also
http://www.php.net/mysql_data_seek
Parameters
mixed$resA SQL result
int$row

Implemented in DatabasePostgres, DatabaseOracle, DatabaseSqlite, DatabaseMysqlBase, DatabaseMssql, DBConnRef, FakeDatabase, and DatabaseTestHelper.

IDatabase::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.

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseOracle, DatabaseSqlite, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseOracle, DatabaseMssql, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMysqlBase, DatabaseMssql, and DBConnRef.

IDatabase::doAtomicSection (   $fname,
  $callback 
)

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::doneWrites ( )

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

Returns
bool

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseOracle, DatabaseSqlite, and DBConnRef.

IDatabase::encodeExpiry (   $expiry)

Encode an expiry time into the DBMS dependent format

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::endAtomic (   $fname = __METHOD__)

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseMssql, DatabaseMysqlBase, and DBConnRef.

IDatabase::fetchObject (   $res)

Fetch the next row from the given result object, in object form. Fields can be retrieved with $row->fieldname, with fields acting like member variables. If no more rows are available, false is returned.

Parameters
ResultWrapper | stdClass$resObject as returned from IDatabase::query(), etc.
Returns
stdClass|bool
Exceptions
DBUnexpectedErrorThrown if the database returns an error

Implemented in DatabasePostgres, DatabaseOracle, DatabaseSqlite, DatabaseMssql, DatabaseMysqlBase, DBConnRef, DatabaseTestHelper, and FakeDatabase.

IDatabase::fetchRow (   $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.

Parameters
ResultWrapper$resResult object as returned from IDatabase::query(), etc.
Returns
array|bool
Exceptions
DBUnexpectedErrorThrown if the database returns an error

Implemented in DatabasePostgres, DatabaseOracle, DatabaseSqlite, DatabaseMysqlBase, DatabaseMssql, DBConnRef, DatabaseTestHelper, and FakeDatabase.

IDatabase::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

Implemented in DatabaseBase, DatabaseMssql, and DBConnRef.

IDatabase::fieldInfo (   $table,
  $field 
)

mysql_fetch_field() wrapper Returns false if the field doesn't exist

Parameters
string$tableTable name
string$fieldField name
Returns
Field

Implemented in DatabasePostgres, DatabaseOracle, DatabaseMssql, DatabaseSqlite, DatabaseMysqlBase, DBConnRef, FakeDatabase, and DatabaseTestHelper.

IDatabase::fieldName (   $res,
  $n 
)

Get a field name in a result object

See Also
http://www.php.net/mysql_field_name
Parameters
mixed$resA SQL result
int$n
Returns
string

Implemented in DatabasePostgres, DatabaseOracle, DatabaseSqlite, DatabaseMysqlBase, DatabaseMssql, DBConnRef, FakeDatabase, and DatabaseTestHelper.

IDatabase::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

Implemented in DatabaseBase, DatabaseOracle, DatabasePostgres, DatabaseSqlite, DatabaseMssql, DatabaseMysqlBase, and DBConnRef.

IDatabase::getDBname ( )

Get the current DB name

Returns
string

Implemented in DatabaseBase, DatabaseOracle, DatabasePostgres, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseOracle, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::getMasterPos ( )

Get the position of this master

Returns
DBMasterPos|bool False if this is not a master

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::getProperty (   $name)

General read-only accessor

Parameters
string$name
Returns
string

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::getServer ( )

Get the server hostname or IP address

Returns
string

Implemented in DatabaseBase, DatabaseOracle, DatabasePostgres, and DBConnRef.

IDatabase::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

Implemented in DatabaseSqlite, DatabaseBase, DatabaseTestHelper, and DBConnRef.

IDatabase::getServerUptime ( )

Determines how long the server has been up STUB

Returns
int

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::getServerVersion ( )

A string describing the current software version, like from mysql_get_server_info().

Returns
string Version information from the database server.

Implemented in DatabasePostgres, DatabaseOracle, DatabaseMssql, DatabaseMysqlBase, DatabaseSqlite, FakeDatabase, DBConnRef, DatabaseTestHelper, and FakeDatabaseMysqlBase.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::getSlavePos ( )

Get the replication position of this slave

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

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::getSoftwareLink ( )

Returns a wikitext link to the DB's website, e.g., return "[http://www.mysql.com/ MySQL]"; Should at least contain plain text, if for some reason your database has no website.

Returns
string Wikitext of a link to the server software's web site

Implemented in DatabasePostgres, DatabaseOracle, DatabaseMssql, DatabaseMysqlBase, DatabaseSqlite, FakeDatabase, DBConnRef, and DatabaseTestHelper.

IDatabase::getType ( )

Get the type of the DBMS, as it appears in $wgDBtype.

Returns
string

Implemented in DatabaseMssql, DatabaseOracle, DatabasePostgres, DBConnRef, DatabaseSqlite, DatabaseTestHelper, DatabaseMysqlBase, and FakeDatabase.

IDatabase::getWikiID ( )
Returns
string

Implemented in DatabaseBase, and DBConnRef.

IDatabase::implicitGroupby ( )

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

Returns
bool

Implemented in DatabaseBase, DatabaseOracle, DatabasePostgres, DatabaseSqlite, DBConnRef, and DatabaseMssql.

IDatabase::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

Implemented in DatabaseBase, DatabaseOracle, DatabasePostgres, DBConnRef, and DatabaseMssql.

IDatabase::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

Implemented in DatabaseBase, DatabaseOracle, and DBConnRef.

IDatabase::indexUnique (   $table,
  $index 
)

Determines if a given index is unique

Parameters
string$table
string$index
Returns
bool

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseSqlite, DatabaseMssql, DatabaseOracle, DBConnRef, and FakeDatabase.

IDatabase::insertId ( )

Get the inserted value of an auto-increment row

The value inserted should be fetched from nextSequenceValue()

Example: $id = $dbw->nextSequenceValue( 'page_page_id_seq' ); $dbw->insert( 'page', array( 'page_id' => $id ) ); $id = $dbw->insertId();

Returns
int

Implemented in DatabasePostgres, DatabaseOracle, DatabaseSqlite, DatabaseMssql, DBConnRef, DatabaseMysqli, FakeDatabase, DatabaseMysql, DatabaseTestHelper, and FakeDatabaseMysqlBase.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseMssql, DatabaseOracle, and DBConnRef.

IDatabase::isOpen ( )

Is a connection to the database open?

Returns
bool

Implemented in DatabaseBase, DatabaseTestHelper, and DBConnRef.

IDatabase::isReadOnly ( )
Returns
bool Whether this DB is read-only
Since
1.27

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::lastError ( )
IDatabase::lastQuery ( )

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

Returns
string

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMysqlBase, DatabasePostgres, DatabaseSqlite, DatabaseOracle, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseMysqlBase, DatabaseSqlite, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseMysqlBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::maxListLen ( )

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

Returns
int

Implemented in DatabaseBase, and DBConnRef.

IDatabase::namedLocksEnqueue ( )

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

Returns
bool
Since
1.26

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseOracle, and DBConnRef.

IDatabase::numFields (   $res)

Get the number of fields in a result object

See Also
http://www.php.net/mysql_num_fields
Parameters
mixed$resA SQL result
Returns
int

Implemented in DatabasePostgres, DatabaseOracle, DatabaseSqlite, DatabaseMysqlBase, DatabaseMssql, DBConnRef, DatabaseTestHelper, and FakeDatabase.

IDatabase::numRows (   $res)

Get the number of rows in a result object

Parameters
mixed$resA SQL result
Returns
int

Implemented in DatabasePostgres, DatabaseOracle, DatabaseSqlite, DatabaseMysqlBase, DatabaseMssql, DBConnRef, DatabaseTestHelper, and FakeDatabase.

IDatabase::onTransactionIdle (   $callback)

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::onTransactionPreCommitOrIdle (   $callback)

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::open (   $server,
  $user,
  $password,
  $dbName 
)

Open a connection to the database. Usually aborts on failure

Parameters
string$serverDatabase server host
string$userDatabase user name
string$passwordDatabase user password
string$dbNameDatabase name
Returns
bool
Exceptions
DBConnectionError

Implemented in DatabaseOracle, DatabasePostgres, DatabaseSqlite, DBConnRef, DatabaseTestHelper, DatabaseMssql, DatabaseMysqlBase, and FakeDatabase.

IDatabase::pendingWriteCallers ( )

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

Returns
array
Since
1.27

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::ping ( )

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

Returns
bool Success or failure

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DBConnRef, DatabaseTestHelper, and DatabaseSqliteMock.

IDatabase::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

Implemented in DatabaseBase, DatabaseSqlite, DatabaseMysqlBase, and DBConnRef.

IDatabase::reportConnectionError (   $error = 'Unknown error')
Parameters
string$errorFallback error message, used if none is given by DB
Exceptions
DBConnectionError

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, and DBConnRef.

IDatabase::rollback (   $fname = __METHOD__,
  $flush = '' 
)

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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.

Implemented in DatabaseBase, DatabaseMssql, and DBConnRef.

IDatabase::selectDB (   $db)

Change the current database

Parameters
string$db
Returns
bool Success or failure

Implemented in DatabaseBase, DatabaseOracle, DatabaseMssql, DatabasePostgres, DBConnRef, DatabaseMysqli, and DatabaseMysql.

IDatabase::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.

Implemented in DatabaseBase, and DBConnRef.

IDatabase::selectFieldValues (   $table,
  $var,
  $cond = '',
  $fname = __METHOD__,
  $options = [] 
)

A SELECT wrapper which returns a list of single field values from result rows.

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|array The values from the field, or false on failure
Since
1.25

Implemented in DBConnRef.

IDatabase::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

Implemented in DatabaseOracle, DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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()

Implemented in DatabaseBase, DatabasePostgres, DatabaseMssql, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DBConnRef, and FakeDatabase.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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.

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::startAtomic (   $fname = __METHOD__)

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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

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

Query whether a given table exists

Parameters
string$table
string$fname
Returns
bool

Implemented in DatabaseBase, DatabaseOracle, DatabaseMssql, DBConnRef, and DatabaseTestHelper.

IDatabase::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.

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseOracle, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseOracle, DatabaseSqlite, and DBConnRef.

IDatabase::unionSupportsOrderAndLimit ( )

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

Returns
bool

Implemented in DatabaseBase, DatabaseSqlite, DBConnRef, and DatabaseMssql.

IDatabase::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

Implemented in DatabaseBase, DatabasePostgres, DatabaseMysqlBase, DatabaseSqlite, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMssql, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMysqlBase, DatabaseOracle, and DBConnRef.

IDatabase::wasDeadlock ( )

Determines if the last failure was due to a deadlock STUB

Returns
bool

Implemented in DatabaseBase, DatabaseMysqlBase, DatabasePostgres, DatabaseOracle, DatabaseSqlite, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, DatabaseMysqlBase, DatabaseSqlite, and DBConnRef.

IDatabase::wasLockTimeout ( )

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

Returns
bool

Implemented in DatabaseBase, DatabaseMysqlBase, and DBConnRef.

IDatabase::wasReadOnlyError ( )

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

Returns
bool

Implemented in DatabaseBase, DatabaseMysqlBase, DatabaseSqlite, and DBConnRef.

IDatabase::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

Implemented in DatabaseBase, and DBConnRef.

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

Implemented in DatabaseBase, and DBConnRef.


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