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Working from the bottom up:
Level 45 is the "core" CSF. This is itself a set of modules with its own internal module hierarchy, but as far as applications are concerned, it is one entity "csf". It is intended to house functionality that:
- changes very infrequently.
- is used by all, or the vast majority, of apps.
Level 3 holds 4 holds services related to what might be called "reference data" or "base data". This data is generally fairly stable - it changes slowly over time - and examples are Subjects, Departments, Terms etc. This functionality:
- changes infrequently.
- is used by many, but not necessarily all, apps.
Level 3 holds services related to "reference data" or "base data", but which aggregates lower-level base data services. An example would be a student's enrolment profile, which aggregates student, course, and term information. This functionality:
- changes infrequently
- is used by many, but not necessarily all, apps.
Level 2 contains services related to business logic, and data that does change frequently. The modules are intended to be scoped around single business processes (e.g. registration, grading, student accounts). This functionality:
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Level 1 is used for modules that need to aggregate services from multiple lower level modules. These modules are intended to be closely related to particular web apps, and the code is not generally meant to be reusable across many apps. business-logic modules. This functionality:
- changes quite frequently.
- is used typically only by one by app.
The levels have these attributes:
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