NEMO/ELMO architecture

See also the auto-generated entity-relationship diagram of our database schema.

Codebase

TODO: Document some of the main files, per the advice of https://matklad.github.io//2021/02/06/ARCHITECTURE.md.html.

Input and output

This summarizes all the ways data can flow in and out of the app. It's important to consider each of these when considering a core change.

Form/Question
- Create/Edit/Delete:
  - Form Builder
  - Replication
- View:
  - Form Builder
  - SMS Guide
  - Printable Form View
  - ODK XML
  - ODK manifest
Response/Answer
- Create:
  - Response Form
  - SMS
  - ODK
- Edit/Delete:
  - Response Form
- View:
  - Response View
  - Search
  - Reports
  - Response List Key Questions (also on dashboard)
  - Dashboard Map
  - API (both legacy and OData)
  - CSV

List of attachment types

Possible ActiveStorage attachments:

Operation.attachment (export)
SavedUpload.file - SavedTabularUpload (import)
Question.media_prompt (shown on questions)
MediaObject.item - Audio, Image, Video (submitted as answers)
Response.odk_xml (raw ODK submissions)

Options, OptionSets, and OptionNodes

For select_one or select_multiple question. May be flat or multi-level.

OptionSet is a collection of Options
Option should be one-to-one with OptionNode (rather vestigial, and eventually being deprecated)
OptionNodes belong to OptionSets, and also to their own parents (they're a tree)

See also the individual models for deeper information.