PHP MDB2_Driver_Common::setLimit方法代码示例

    /**
     * Gets a recordset of tag dataobjects.
     *
     * @param SwatDBRange $range optional. Range of tags to retrieve. If not
     *                           specified, all tags are loaded.
     * @param string $order_by_clause optional. SQL order by clause of the tag
     *                                list.
     *
     * @return PinholeTagDataObjectWrapper
     */
    private function getSubTagDataObjects(SwatDBRange $range = null, $order_by_clause = null)
    {
        $args = func_get_args();
        $cache_key = $this->getCacheKey(__FUNCTION__, $args);
        $value = $this->app->getCacheRecordset($cache_key, 'PinholeTagDataObjectWrapper', 'photos');
        if ($value !== false) {
            return $value;
        }
        if ($order_by_clause === null) {
            $order_by_clause = 'PinholeTagDateView.first_modified desc';
        }
        $sql = sprintf('select PinholeTag.*,
				PinholeTagDateView.first_modified,
				PinholeTagDateView.last_modified
			from PinholeTag
			inner join PinholeTagDateView on
				PinholeTagDateView.tag = PinholeTag.id
			where %s
			order by %s', $this->getSubTagWhereClause(), $order_by_clause);
        if ($range !== null) {
            $this->db->setLimit($range->getLimit(), $range->getOffset());
        }
        $tag_data_objects = SwatDB::query($this->db, $sql, 'PinholeTagDataObjectWrapper');
        $this->app->addCacheRecordset($tag_data_objects, $cache_key, 'photos');
        return $tag_data_objects;
    }

 /**
  * @brief Prepare a SQL query
  * @param string $query Query string
  * @param int $limit
  * @param int $offset
  * @return MDB2_Statement_Common prepared SQL query
  *
  * SQL query via MDB2 prepare(), needs to be execute()'d!
  */
 public static function prepare($query, $limit = null, $offset = null)
 {
     if (!is_null($limit) && $limit != -1) {
         if (self::$backend == self::BACKEND_MDB2) {
             //MDB2 uses or emulates limits & offset internally
             self::$MDB2->setLimit($limit, $offset);
         } else {
             //PDO does not handle limit and offset.
             //FIXME: check limit notation for other dbs
             //the following sql thus might needs to take into account db ways of representing it
             //(oracle has no LIMIT / OFFSET)
             $limit = (int) $limit;
             $limitsql = ' LIMIT ' . $limit;
             if (!is_null($offset)) {
                 $offset = (int) $offset;
                 $limitsql .= ' OFFSET ' . $offset;
             }
             //insert limitsql
             if (substr($query, -1) == ';') {
                 //if query ends with ;
                 $query = substr($query, 0, -1) . $limitsql . ';';
             } else {
                 $query .= $limitsql;
             }
         }
     }
     // Optimize the query
     $query = self::processQuery($query);
     self::connect();
     // return the result
     if (self::$backend == self::BACKEND_MDB2) {
         $result = self::$connection->prepare($query);
         // Die if we have an error (error means: bad query, not 0 results!)
         if (PEAR::isError($result)) {
             $entry = 'DB Error: "' . $result->getMessage() . '"<br />';
             $entry .= 'Offending command was: ' . htmlentities($query) . '<br />';
             OC_Log::write('core', $entry, OC_Log::FATAL);
             error_log('DB error: ' . $entry);
             OC_Template::printErrorPage($entry);
         }
     } else {
         try {
             $result = self::$connection->prepare($query);
         } catch (PDOException $e) {
             $entry = 'DB Error: "' . $e->getMessage() . '"<br />';
             $entry .= 'Offending command was: ' . htmlentities($query) . '<br />';
             OC_Log::write('core', $entry, OC_Log::FATAL);
             error_log('DB error: ' . $entry);
             OC_Template::printErrorPage($entry);
         }
         $result = new PDOStatementWrapper($result);
     }
     return $result;
 }

 /**
  * Private method that will use MDB2_Driver_Common::query() for simple and
  * MDB2_Driver_Common::prepare() & MDB2_Statement_Common::execute() for complex
  * query specifications.
  *
  * @param mixed  $sql        A string or an array.
  * @param string $configPath The config path used for exception messages.
  *
  * @return MDB2_Result
  * @throws XML_Query2XML_DBException If a database related error occures.
  */
 private function _prepareAndExecute($sql, $configPath)
 {
     $preparedQuery = $sql['query'];
     if (isset($sql['limit'])) {
         $preparedQuery .= '; LIMIT:' . $sql['limit'];
         $preparedQuery .= '; OFFSET:' . $sql['offset'];
         $this->_db->setLimit($sql['limit'], $sql['offset']);
     }
     if (isset($this->_preparedQueries[$preparedQuery])) {
         $queryHandle = $this->_preparedQueries[$preparedQuery];
     } else {
         // PREPARE
         $queryHandle = $this->_db->prepare($sql['query']);
         if (PEAR::isError($queryHandle)) {
             /*
              * unit tests: (only if mysql or pgsql is used)
              *  MDB2/_prepareAndExecute/throwDBException_complexQuery.phpt
              */
             throw new XML_Query2XML_DBException($configPath . ': Could not prepare the following SQL query: ' . $sql['query'] . '; ' . $queryHandle->toString());
         }
         $this->_preparedQueries[$preparedQuery] =& $queryHandle;
     }
     // EXECUTE
     if (isset($sql['data'])) {
         $result = $queryHandle->execute($sql['data']);
     } else {
         $result = $queryHandle->execute();
     }
     if (PEAR::isError($result)) {
         /*
          * unit tests:
          *  if sqlite is used: MDB2/_prepareAndExecute/
          *   throwDBException_complexQuery.phpt
          *  if sqlite or mysql is sued: MDB2/getXML/
          *   throwDBException_nullResultSet_complexQuery_multipleRecords.phpt
          *   throwDBException_nullResultSet_complexQuery_singleRecord.phpt
          */
         throw new XML_Query2XML_DBException($configPath . ': Could not execute the following SQL query: ' . $sql['query'] . '; ' . $result->toString());
     }
     return $result;
 }

    public function getPostByDateAndShortname(SwatDate $date, $shortname)
    {
        $post = false;
        if ($this->memcache !== null) {
            $key = $date->formatLikeIntl('yyyyMMdd') . $shortname;
            $key = $this->getPostCacheKey($key);
            $post = $this->memcache->getNs('posts', $key);
        }
        if ($post === false) {
            $sql = $this->getSelectClause();
            $sql .= $this->getWhereClause();
            $sql .= sprintf(' and BlorgPost.shortname = %s and
				date_trunc(\'month\', convertTZ(publish_date, %s)) =
					date_trunc(\'month\', timestamp %s)', $this->db->quote($shortname, 'text'), $this->db->quote($date->getTimezone()->getName(), 'text'), $this->db->quote($date->getDate(), 'date'));
            $this->db->setLimit(1, 0);
            $post_wrapper = SwatDBClassMap::get('BlorgPostWrapper');
            $posts = SwatDB::query($this->db, $sql, $post_wrapper);
            if (in_array('author', $this->fields)) {
                $this->loadPostAuthors($posts);
            }
            if ($this->load_files) {
                $this->loadPostFiles($posts);
            }
            if ($this->load_tags) {
                $this->loadPostTags($posts);
            }
            $post = $posts->getFirst();
            if ($this->memcache !== null) {
                $this->memcache->setNs('posts', $key, $post);
            }
        } else {
            if ($post !== null) {
                $post->setDatabase($this->db);
            }
        }
        return $post;
    }

 /**
  * @brief Prepare a SQL query
  * @param string $query Query string
  * @param int $limit
  * @param int $offset
  * @param bool $isManipulation
  * @return MDB2_Statement_Common prepared SQL query
  *
  * SQL query via MDB2 prepare(), needs to be execute()'d!
  */
 public static function prepare($query, $limit = null, $offset = null, $isManipulation = null)
 {
     if (!is_null($limit) && $limit != -1) {
         if (self::$backend == self::BACKEND_MDB2) {
             //MDB2 uses or emulates limits & offset internally
             self::$MDB2->setLimit($limit, $offset);
         } else {
             //PDO does not handle limit and offset.
             //FIXME: check limit notation for other dbs
             //the following sql thus might needs to take into account db ways of representing it
             //(oracle has no LIMIT / OFFSET)
             $limit = (int) $limit;
             $limitsql = ' LIMIT ' . $limit;
             if (!is_null($offset)) {
                 $offset = (int) $offset;
                 $limitsql .= ' OFFSET ' . $offset;
             }
             //insert limitsql
             if (substr($query, -1) == ';') {
                 //if query ends with ;
                 $query = substr($query, 0, -1) . $limitsql . ';';
             } else {
                 $query .= $limitsql;
             }
         }
     } else {
         if (isset(self::$preparedQueries[$query]) and self::$cachingEnabled) {
             return self::$preparedQueries[$query];
         }
     }
     $rawQuery = $query;
     // Optimize the query
     $query = self::processQuery($query);
     self::connect();
     if ($isManipulation === null) {
         //try to guess, so we return the number of rows on manipulations
         $isManipulation = self::isManipulation($query);
     }
     // return the result
     if (self::$backend == self::BACKEND_MDB2) {
         // differentiate between query and manipulation
         if ($isManipulation) {
             $result = self::$connection->prepare($query, null, MDB2_PREPARE_MANIP);
         } else {
             $result = self::$connection->prepare($query, null, MDB2_PREPARE_RESULT);
         }
         // Die if we have an error (error means: bad query, not 0 results!)
         if (self::isError($result)) {
             throw new DatabaseException($result->getMessage(), $query);
         }
     } else {
         try {
             $result = self::$connection->prepare($query);
         } catch (PDOException $e) {
             throw new DatabaseException($e->getMessage(), $query);
         }
         // differentiate between query and manipulation
         $result = new PDOStatementWrapper($result, $isManipulation);
     }
     if (is_null($limit) || $limit == -1 and self::$cachingEnabled) {
         $type = OC_Config::getValue("dbtype", "sqlite");
         if ($type != 'sqlite' && $type != 'sqlite3') {
             self::$preparedQueries[$rawQuery] = $result;
         }
     }
     return $result;
 }