group_by_dj.py

# When acquisition is inserted, the number of images is known
# and all metadata can be inserted.
class Acquisition(dj.Computed):
  definition = """
  acq_name: varchar(32)
  """
  class ImageMetadata(dj.Part):
    definition = """
    -> Acquisition
    -> image_index: int
    """

# Image seems like it should each be a Part table, but it is inserted
# independently when data comes available.
class Image(dj.Manual):
  definition = """
  -> Acquisition.ImageMetadata
  """

 
class ProcessImage(dj.Computed):
  definition = """
  -> Image
  -> Params  # not shown here
  """

# Need to manually spell out the key here, as there is no
# correct upstream table to reference.  I'd also like it
# to be deleted whenever any ProcessImage gets removed.
class ProcessingComplete():
  definition = """
  -> Acquisition
  -> Params
  """
  def make(...):
    if num_metadata == num_processed:
      self.insert1()