Utility to import into pandas dataframe output of read functions

[emiliom]

Starting a focused issue on this specific functionality, instead of the overly broad issue #164. Will copy over comments on this, later.

Goals

• Aiming for a completely generic function, not hard wired to any specific entity. That may be overly ambitious, though ...
• Focused on core entities

Issues I've encountered, and either solved or not solved yet, including (to be updated):

• Functionality to identify the primary key column
• Polymorphic classes require special handling, distinct from simpler classes
• What to do about the "object" attributes that point to related entities

[emiliom]

Relevant comments from related issues:

Anthony:

I also believe that -- given that Pandas has become a core part of the standard Python computational science and data science stack -- that we should consider strong integration with Pandas and GeoPandas as core functionality. This is especially true given that one of the highest priorities we've heard from users and potential users is to improve I/O performance (including data alignment and slicing), and that is one of the main purposes/advantages of using Pandas.

Let's please include at least a lightweight Pandas integration in odm2api. I would suggest that we should have Pandas integration at the core of ODM2 software, and that we already have a confusing number of non-integrated repos. Let's consolidate rather than split, especially for such a fundamental package as Pandas

Jeff:

Utility functions would be nice. Is there ongoing work that's driving this?

I don't really have issues with you moving forward with the ODM2API stuff that you have been working on. The Pandas dataframe idea is good.