Unified Open R&D: compare program/course models in Open and our other projects

[rhysyngsun]

See also: https://docs.google.com/document/d/1pHTqQ3nWT348RyTLcCdUH9gHjLU7erKfqqa2oXiz_qY/edit

We have some existing models and APIs for programs, courses, course runs, etc. We need to figure out whether we use these going forward for other functionality like ecommerce or whether it's better to have separate data models (and effectively treat search like it's a separate service even though it's cohosted) and use the product/ecommerce/enrollment and just another source of truth that's ingested into the search data.

• [ ] Document how search vs. dashboard, ecommerce, etc use these
• [ ] Tradeoffs of separate models vs a single model
  • Consider how overloading the search models to be both a projection of external course data and a source of truth for Open's course data could cause problems.
  • How does either approach fit into a future possibility of moving the search data ingestion into a separate data pipeline?
  • Are there any concerns of one data model that conflict with another?
  • How do these approaches impact how we build the frontend?
  • Are there any alternatives not considered yet?

[collinpreston]

Considering the tiny amount of overlap between the two data models, I think it would be best to have an e-commerce model structure that exists separately from the current course-catalog model structure. Additionally, having a separate data model for e-commerce would allow us to build e-commerce functionality into it's own service, or migrate to a different e-commerce solution if we wanted to do so in the future.

So to help understand what models would generally be required to support our e-commerce requirements, I sketched out an ER diagram:

I also generated a similar ER diagram for the current course-catalog application in Open:

The course-catalog model structure is much more elaborate than the proposed e-commerce structure. The only piece of data shared between both model structures is "price" which is used during filtering and the front-end when displaying courses and programs.

You can view both model structure ER diagrams here