Remove All Enumeration Types

Summary of outcomes for Data Standard 3.0

• Problem Addressed: The descriptor/type pattern prior to v3.0 was unnecessary and confusing and generated complexity in downstream API implementations. The value gained from restricting type enumerations and forcing descriptor mappings to types provided little value relative to the complexity.
• High-level Reasoning: By eliminating types (including descriptor map types), much of this complexity may be alleviated. Instead, the Ed-Fi standard descriptor values will be managed in descriptor xml files in the Ed-Fi namespace.
• Changes Made: All types (with the exception of SchoolYear) were converted to descriptors and a descriptor xml file was created for each converted type to contain the standard values. All descriptor map types were removed and all former map type values were reconciled against the existing descriptor xml files to ensure that all values were properly maintained. The SchoolYear "type" was left as-is, as SchoolYear is not a true type.

Original ticket description follows:

Consistent with community deliberations on the issues with the current Ed-Fi UDM and downstream support for enumerations (see the Enumerations SIG and also a common topic in 2017 TAG - see meeting notes), the task is to eliminate Types from the model, and replace these with the concept of "core" enumerations. 

The core issue was that the current descriptor/type pattern in the UDM was that it is unnecessary and confusing. The concept of Ed-Fi governed values (formerly Types) can equally well be supported by properly namespaced descriptors (the "core" enumeration values in an "ed-fi.org" namespace). The practice of forcing mappings to a Type when that type provided no value to particular data exchange context was one example of such confusion.

In practice the Type pattern also generated complexity in downstream API implementations, as storage and usage patterns varied in field work.

Implementers of Ed-Fi APIs (including the Ed-Fi ODS and API) are  - if needed - expected to allow for mappings between enumeration sets to support use cases where data must move between various contexts. Ed-Fi API and other standards will call out expectations for particular sets as part of those standards.

Key tasks for this ticket:

• Enumeration types will be removed and replaced with descriptors.
• Descriptor map types will be removed from the model.
• Sample xml files will be created to contain the enumeration values for types that are being eliminated.