databasepostgres.php

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				return '"' . $name . '"';

			default:
				return $name;
		}
	}

	/**
	 * Return the next in a sequence, save the value for retrieval via insertId()
	 */
	function nextSequenceValue( $seqName ) {
		$safeseq = preg_replace( "/'/", "''", $seqName );
		$res = $this->query( "SELECT nextval('$safeseq')" );
		$row = $this->fetchRow( $res );
		$this->mInsertId = $row[0];
		$this->freeResult( $res );
		return $this->mInsertId;
	}

	/**
	 * USE INDEX clause
	 * PostgreSQL doesn't have them and returns ""
	 */
	function useIndexClause( $index ) {
		return '';
	}

	# REPLACE query wrapper
	# PostgreSQL simulates this with a DELETE followed by INSERT
	# $row is the row to insert, an associative array
	# $uniqueIndexes is an array of indexes. Each element may be either a
	# field name or an array of field names
	#
	# 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
	function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
		$table = $this->tableName( $table );

		if (count($rows)==0) {
			return;
		}

		# Single row case
		if ( !is_array( reset( $rows ) ) ) {
			$rows = array( $rows );
		}

		foreach( $rows as $row ) {
			# Delete rows which collide
			if ( $uniqueIndexes ) {
				$sql = "DELETE FROM $table WHERE ";
				$first = true;
				foreach ( $uniqueIndexes as $index ) {
					if ( $first ) {
						$first = false;
						$sql .= "(";
					} else {
						$sql .= ') OR (';
					}
					if ( is_array( $index ) ) {
						$first2 = true;
						foreach ( $index as $col ) {
							if ( $first2 ) {
								$first2 = false;
							} else {
								$sql .= ' AND ';
							}
							$sql .= $col.'=' . $this->addQuotes( $row[$col] );
						}
					} else {
						$sql .= $index.'=' . $this->addQuotes( $row[$index] );
					}
				}
				$sql .= ')';
				$this->query( $sql, $fname );
			}

			# Now insert the row
			$sql = "INSERT INTO $table (" . $this->makeList( array_keys( $row ), LIST_NAMES ) .') VALUES (' .
				$this->makeList( $row, LIST_COMMA ) . ')';
			$this->query( $sql, $fname );
		}
	}

	# DELETE where the condition is a join
	function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = "Database::deleteJoin" ) {
		if ( !$conds ) {
			throw new DBUnexpectedError($this,  'Database::deleteJoin() called with empty $conds' );
		}

		$delTable = $this->tableName( $delTable );
		$joinTable = $this->tableName( $joinTable );
		$sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
		if ( $conds != '*' ) {
			$sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
		}
		$sql .= ')';

		$this->query( $sql, $fname );
	}

	# Returns the size of a text field, or -1 for "unlimited"
	function textFieldSize( $table, $field ) {
		$table = $this->tableName( $table );
		$sql = "SELECT t.typname as ftype,a.atttypmod as size
			FROM pg_class c, pg_attribute a, pg_type t
			WHERE relname='$table' AND a.attrelid=c.oid AND
				a.atttypid=t.oid and a.attname='$field'";
		$res =$this->query($sql);
		$row=$this->fetchObject($res);
		if ($row->ftype=="varchar") {
			$size=$row->size-4;
		} else {
			$size=$row->size;
		}
		$this->freeResult( $res );
		return $size;
	}

	function lowPriorityOption() {
		return '';
	}

	function limitResult($sql, $limit,$offset) {
		return "$sql LIMIT $limit ".(is_numeric($offset)?" OFFSET {$offset} ":"");
	}

	/**
	 * Returns an SQL expression for a simple conditional.
	 * Uses CASE on PostgreSQL.
	 *
	 * @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
	 */
	function conditional( $cond, $trueVal, $falseVal ) {
		return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
	}

	# FIXME: actually detecting deadlocks might be nice
	function wasDeadlock() {
		return false;
	}

	# Return DB-style timestamp used for MySQL schema
	function timestamp( $ts=0 ) {
		return wfTimestamp(TS_DB,$ts);
	}

	/**
	 * Return aggregated value function call
	 */
	function aggregateValue ($valuedata,$valuename='value') {
		return $valuedata;
	}


	function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
		$message = "A database error has occurred\n" .
			"Query: $sql\n" .
			"Function: $fname\n" .
			"Error: $errno $error\n";
		throw new DBUnexpectedError($this, $message);
	}

	/**
	 * @return string wikitext of a link to the server software's web site
	 */
	function getSoftwareLink() {
		return "[http://www.postgresql.org/ PostgreSQL]";
	}

	/**
	 * @return string Version information from the database
	 */
	function getServerVersion() {
		$res = $this->query( "SELECT version()" );
		$row = $this->fetchRow( $res );
		$version = $row[0];
		$this->freeResult( $res );
		return $version;
	}


	/**
	 * Query whether a given table exists (in the given schema, or the default mw one if not given)
	 */
	function tableExists( $table, $schema = false ) {
		global $wgDBmwschema;
		if (! $schema )
			$schema = $wgDBmwschema;
		$etable = preg_replace("/'/", "''", $table);
		$eschema = preg_replace("/'/", "''", $schema);
		$SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
			. "WHERE c.relnamespace = n.oid AND c.relname = '$etable' AND n.nspname = '$eschema'";
		$res = $this->query( $SQL );
		$count = $res ? pg_num_rows($res) : 0;
		if ($res)
			$this->freeResult( $res );
		return $count;
	}


	/**
	 * Query whether a given schema exists. Returns the name of the owner
	 */
	function schemaExists( $schema ) {
		$eschema = preg_replace("/'/", "''", $schema);
		$SQL = "SELECT rolname FROM pg_catalog.pg_namespace n, pg_catalog.pg_roles r "
				."WHERE n.nspowner=r.oid AND n.nspname = '$eschema'";
		$res = $this->query( $SQL );
		$owner = $res ? pg_num_rows($res) ? pg_fetch_result($res, 0, 0) : false : false;
		if ($res)
			$this->freeResult($res);
		return $owner;
	}

	/**
	 * Query whether a given column exists in the mediawiki schema
	 */
	function fieldExists( $table, $field ) {
		global $wgDBmwschema;
		$etable = preg_replace("/'/", "''", $table);
		$eschema = preg_replace("/'/", "''", $wgDBmwschema);
		$ecol = preg_replace("/'/", "''", $field);
		$SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n, pg_catalog.pg_attribute a "
			. "WHERE c.relnamespace = n.oid AND c.relname = '$etable' AND n.nspname = '$eschema' "
			. "AND a.attrelid = c.oid AND a.attname = '$ecol'";
		$res = $this->query( $SQL );
		$count = $res ? pg_num_rows($res) : 0;
		if ($res)
			$this->freeResult( $res );
		return $count;
	}

	function fieldInfo( $table, $field ) {
		$res = $this->query( "SELECT $field FROM $table LIMIT 1" );
		$type = pg_field_type( $res, 0 );
		return $type;
	}

	function begin( $fname = 'DatabasePostgrs::begin' ) {
		$this->query( 'BEGIN', $fname );
		$this->mTrxLevel = 1;
	}
	function immediateCommit( $fname = 'DatabasePostgres::immediateCommit' ) {
		return true;
	}
	function commit( $fname = 'DatabasePostgres::commit' ) {
		$this->query( 'COMMIT', $fname );
		$this->mTrxLevel = 0;
	}

	/* Not even sure why this is used in the main codebase... */
	function limitResultForUpdate($sql, $num) {
		return $sql;
	}

	function update_interwiki() {
		## Avoid the non-standard "REPLACE INTO" syntax
		## Called by config/index.php
		$f = fopen( "../maintenance/interwiki.sql", 'r' );
		if ($f == false ) {
			dieout( "<li>Could not find the interwiki.sql file");
		}
		## We simply assume it is already empty as we have just created it
		$SQL = "INSERT INTO interwiki(iw_prefix,iw_url,iw_local) VALUES ";
		while ( ! feof( $f ) ) {
			$line = fgets($f,1024);
			if (!preg_match("/^\s*(\(.+?),(\d)\)/", $line, $matches)) {
				continue;
			}
			$yesno = $matches[2]; ## ? "'true'" : "'false'";
			$this->query("$SQL $matches[1],$matches[2])");
		}
		print " (table interwiki successfully populated)...\n";
	}

	function encodeBlob($b) {
		return array('bytea',pg_escape_bytea($b));
	}
	function decodeBlob($b) {
		return pg_unescape_bytea( $b );
	}

	function strencode( $s ) { ## Should not be called by us
		return pg_escape_string( $s );
	}

	function addQuotes( $s ) {
		if ( is_null( $s ) ) {
			return 'NULL';
		} else if (is_array( $s )) { ## Assume it is bytea data
			return "E'$s[1]'";
		}
		return "'" . pg_escape_string($s) . "'";
		return "E'" . pg_escape_string($s) . "'";
	}

}

?>