}
/**
- * USE INDEX clause
- * PostgreSQL doesn't have them and returns ""
+ * 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.
*/
function useIndexClause( $index ) {
- return "FORCE INDEX (" . $this->indexName( $index ) . ")";
+ return '';
}
/**
}
/**
+ * 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.
+ *
* @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
*/
function lowPriorityOption() {
- return 'LOW_PRIORITY';
+ return '';
}
/**
}
/**
- * Construct a LIMIT query with optional offset
- * This is used for query pages
+ * 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. For
+ * UPDATE, limitResultForUpdate should be used.
+ *
+ * The version provided by default works in MySQL and SQLite. It will very
+ * likely need to be overridden for most other DBMSes.
+ *
* @param $sql String: SQL query we will append the limit too
* @param $limit Integer: the SQL limit
* @param $offset Integer the SQL offset (default false)
*/
- function limitResult($sql, $limit, $offset=false) {
- if( !is_numeric($limit) ) {
+ function limitResult( $sql, $limit, $offset=false ) {
+ if( !is_numeric( $limit ) ) {
throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
}
return "$sql LIMIT "
. ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
. "{$limit} ";
}
- function limitResultForUpdate($sql, $num) {
- return $this->limitResult($sql, $num, 0);
+ function limitResultForUpdate( $sql, $num ) {
+ return $this->limitResult( $sql, $num, 0 );
}
/**
}
/**
- * Returns an SQL expression for a simple conditional.
- * Uses IF on MySQL.
+ * Returns an SQL expression for a simple conditional. This doesn't need
+ * to be overridden unless CASE isn't supported in your DBMS.
*
* @param $cond String: SQL expression which will result in a boolean value
* @param $trueVal String: SQL expression to return if true
* @return String: SQL fragment
*/
function conditional( $cond, $trueVal, $falseVal ) {
- return " IF($cond, $trueVal, $falseVal) ";
+ return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
}
/**
}
/**
+ * Returns a wikitext link to the DB's website, e.g.,
+ * return "[http://www.mysql.com/ MySQL]";
+ * Should probably be overridden to at least contain plain text, if for
+ * some reason your database has no website.
+ *
* @return String: wikitext of a link to the server software's web site
*/
function getSoftwareLink() {
- return "[http://www.mysql.com/ MySQL]";
+ return '(no software link given)';
}
/**
+ * A string describing the current software version, like from
+ * mysql_get_server_info(). Will be listed on Special:Version, etc.
+ *
* @return String: Version information from the database
*/
abstract function getServerVersion();
}
/**
- * Override database's default connection timeout.
- * May be useful for very long batch queries such as
- * full-wiki dumps, where a single query reads out
- * over hours or days.
+ * Override database's default connection timeout. May be useful for very
+ * long batch queries such as full-wiki dumps, where a single query reads
+ * out over hours or days. May or may not be necessary for non-MySQL
+ * databases. For most purposes, leaving it as a no-op should be fine.
+ *
* @param $timeout Integer in seconds
*/
- public function setTimeout( $timeout ) {
- $this->query( "SET net_read_timeout=$timeout" );
- $this->query( "SET net_write_timeout=$timeout" );
- }
+ public function setTimeout( $timeout ) {}
/**
* Read and execute SQL commands from a file.
return db2_num_rows( $this->mLastResult );
}
- /**
- * USE INDEX clause
- * DB2 doesn't have them and returns ""
- * @param sting $index
- */
- public function useIndexClause( $index ) {
- return "";
- }
-
/**
* Simulates REPLACE with a DELETE followed by INSERT
* @param $table Object
return "[http://www.ibm.com/software/data/db2/express/?s_cmp=ECDDWW01&s_tact=MediaWiki IBM DB2]";
}
- /**
- * Returns an SQL expression for a simple conditional.
- * Uses CASE on DB2
- *
- * @param string $cond SQL expression which will result in a boolean value
- * @param string $trueVal SQL expression to return if true
- * @param string $falseVal SQL expression to return if false
- * @return string SQL fragment
- */
- public function conditional( $cond, $trueVal, $falseVal ) {
- return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
- }
-
###
# Fix search crash
###
* @deprecated
*/
public function getStatus( $which ) { wfDebug('Not implemented for DB2: getStatus()'); return ''; }
- /**
- * Not implemented
- * @deprecated
- */
- public function setTimeout( $timeout ) { wfDebug('Not implemented for DB2: setTimeout()'); }
/**
* Not implemented
* TODO
* @deprecated
*/
public function limitResultForUpdate($sql, $num) { return $sql; }
- /**
- * No such option
- * @return string ''
- * @deprecated
- */
- public function lowPriorityOption() { return ''; }
######################################
# Reflection
return str_replace("'","''",$s);
}
- /**
- * USE INDEX clause
- */
- function useIndexClause( $index ) {
- return "";
- }
-
/**
* REPLACE query wrapper
* PostgreSQL simulates this with a DELETE followed by INSERT
return $sql;
}
- /**
- * Returns an SQL expression for a simple conditional.
- *
- * @param $cond String: SQL expression which will result in a boolean value
- * @param $trueVal String: SQL expression to return if true
- * @param $falseVal String: SQL expression to return if false
- * @return string SQL fragment
- */
- function conditional( $cond, $trueVal, $falseVal ) {
- return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
- }
-
/**
* Should determine if the last failure was due to a deadlock
* @return bool
return $sql;
}
- /**
- * not done
- */
- public function setTimeout($timeout) { return; }
-
/**
* How lagged is this slave?
*/
function getServerVersion() {
return mysql_get_server_info( $this->mConn );
}
+
+ function useIndexClause( $index ) {
+ return "FORCE INDEX (" . $this->indexName( $index ) . ")";
+ }
+
+ function lowPriorityOption() {
+ return 'LOW_PRIORITY';
+ }
+
+ function getSoftwareLink() {
+ return '[http://www.mysql.com/ MySQL]';
+ }
+
+ public function setTimeout( $timeout ) {
+ $this->query( "SET net_read_timeout=$timeout" );
+ $this->query( "SET net_write_timeout=$timeout" );
+ }
}
/**
return $this->mInsertId;
}
- /**
- * Oracle does not have a "USE INDEX" clause, so return an empty string
- */
- function useIndexClause($index) {
- return '';
- }
-
# REPLACE query wrapper
# Oracle simulates this with a DELETE followed by INSERT
# $row is the row to insert, an associative array
return $size;
}
- function lowPriorityOption() {
- return '';
- }
-
function limitResult($sql, $limit, $offset) {
if ($offset === false)
$offset = 0;
return 'SELECT * '.($all?'':'/* UNION_UNIQUE */ ').'FROM ('.implode( $glue, $sqls ).')' ;
}
- /**
- * Returns an SQL expression for a simple conditional.
- * Uses CASE on Oracle
- *
- * @param $cond String: SQL expression which will result in a boolean value
- * @param $trueVal String: SQL expression to return if true
- * @param $falseVal String: SQL expression to return if false
- * @return String: SQL fragment
- */
- function conditional( $cond, $trueVal, $falseVal ) {
- return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
- }
-
function wasDeadlock() {
return $this->lastErrno() == 'OCI-00060';
}
return 'BITOR('.$fieldLeft.', '.$fieldRight.')';
}
- public function setTimeout( $timeout ) {
- // @todo fixme no-op
- }
-
/**
* How lagged is this slave?
*
return $currval;
}
- /**
- * Postgres does not have a "USE INDEX" clause, so return an empty string
- */
- function useIndexClause( $index ) {
- return '';
- }
-
# REPLACE query wrapper
# Postgres simulates this with a DELETE followed by INSERT
# $row is the row to insert, an associative array
return $size;
}
- function lowPriorityOption() {
- return '';
- }
-
function limitResult($sql, $limit, $offset=false) {
return "$sql LIMIT $limit ".(is_numeric($offset)?" OFFSET {$offset} ":"");
}
- /**
- * Returns an SQL expression for a simple conditional.
- * Uses CASE on Postgres
- *
- * @param $cond String: SQL expression which will result in a boolean value
- * @param $trueVal String: SQL expression to return if true
- * @param $falseVal String: SQL expression to return if false
- * @return String: SQL fragment
- */
- function conditional( $cond, $trueVal, $falseVal ) {
- return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
- }
-
function wasDeadlock() {
return $this->lastErrno() == '40P01';
}
return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
}
- public function setTimeout( $timeout ) {
- // @todo fixme no-op
- }
-
/**
* How lagged is this slave?
*
return $ret;
}
- /**
- * SQLite does not have a "USE INDEX" clause, so return an empty string
- */
- function useIndexClause($index) {
- return '';
- }
-
/**
* Returns the size of a text field, or -1 for "unlimited"
* In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
return -1;
}
- /**
- * No low priority option in SQLite
- */
- function lowPriorityOption() {
- return '';
- }
-
- /**
- * Returns an SQL expression for a simple conditional.
- * - uses CASE on SQLite
- */
- function conditional($cond, $trueVal, $falseVal) {
- return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
- }
-
function wasDeadlock() {
return $this->lastErrno() == SQLITE_BUSY;
}
function quote_ident($s) { return $s; }
- /**
- * not done
- */
- public function setTimeout($timeout) { return; }
-
/**
* How lagged is this slave?
*/
dépôts / lhc / web / wiklou.git / commitdiff