def Query(self, filter_string="", filter_obj=None):
    # An empty filter string returns all the children.
    if not filter_string:
      return self.OpenChildren(mode=self.mode)

    # Parse the query string
    ast = aff4.AFF4QueryParser(filter_string).Parse()

    # Query our own data store
    filter_obj = ast.Compile(aff4.AFF4Filter)

    return filter_obj.Filter(self.OpenChildren(mode=self.mode))
Get the column name of the primary key for the given table.
dataset/ETHPy150Open google/grr/grr/lib/aff4_objects/timeline.py/GRRTimeSeries.Query--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/db/backends/sqlite3/introspection.py/DatabaseIntrospection.get_primary_key_column