Philosophy & Design Goals

Prepare applications for the next 30 Years
Don't Rewrite. Re-Think, Re-Invent and Re-design
Reproduce the capabilities of Classic.
- The "What", not the "How". What it does is similar. How it's done is different.
- Implement minimum business rules. Leave the rest to customization.
Design to be agnostic regarding:
- Server Location
- Operating System and Platform
- Existence of ITCs

Technical Architecture

Independent Installable Features
Types of Modules:
- Infrastructure (database, email)
- Behavioral (business logic)
- Required
- Optional (authentication)

Object Oriented
Abstraction of underlying Database tables
- Simplifies tables
- Correctly linked to related objects
Dynamic
Primary key (Database Id)
- Automatically assigned by system
- Immutable
- Random UUID
- Used in relationships between objects
Natural Id
- User or Auto assigned identifier
- Human-readable reference number
- May be mutable
- Not used in relationships
https://usas.docs.ssdt.io/current/model/
https://usps.docs.ssdt.io/current/model/

If operation fails (due to crash):
- USxS transaction can be partial posted
- Files left in inconsistent state (out of balance)
Example: Post Purchase Order steps:
- Write PO header record
- Loop for each PO Item:
  - Write item record
  - Update encumbrances on budget
  - Update encumbrances on appropriation
  - Update encumbrances on cash
- If any of the steps fail, files can be out of balance

SQL Databases provide "Transactional Scope"
All operations within scope guaranteed to, either:
- Succeed completely (commit)
- Fail completely (rollback)
Any error causes rollback:
- Duplicate key
- Validation error
- Security violation
- System failure