code: public function update($table, $data = array(), $where = '1=1')
      {
          if (! $this->getDb()->update($table, $data, $where)) {
              throw new DbException("Failed updating " . $table);
          }
          
          return true;
      }
docs: Updates a table
  
  @param string $table
  @param array $data
  @param string $where