Multiple '---' in definition are allowed but can lead to confusion

[guzman-raphael]

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Bug Report

Description

A user decides to include multiple lines beginning with '---' and no error was thrown while parsing. This can lead to confusion as user believes that this has been accepted as correct definition format. Expectation would be to throw an error so that user can be explicit in defining which are primary key attributes and which are secondary attributes.

Reproducibility

Include:

• OS: Linux
• Python Version: 3.8.1
• MySQL Version: 5.7
• MySQL Deployment Strategy: local-docker
• DataJoint Version: 0.12.7
• Steps:

  import datajoint as dj
  schema = dj.Schema('test')
  
  @schema
  class Flight(dj.Manual):
    definition = """
    flight_no  : int
    ---
    economy_price : decimal(6,2)
    departure : datetime
    arrival : datetime 
    ---
    origin_code : int
    dest_code : int
    """
  
    print(Flight())
  

Expected Behavior

Expected to throw DataJointError error.

Additional Research and Context

• StackOverflow user recently asked a question where his definition was stated in this way.
• In terms of addressing, this is likely a good place to start.