Chapter 4 Worked Solutions

Task 1 — Type review (starter set)

• Loan No. → Code[20] (structured identifier, compact and searchable).
• Installment No. → Integer (ordered numeric sequence).
• Principal Amount → Decimal (money-safe precision).
• Paid → Boolean (binary business state).
• Due Date → Date (date-only business deadline).
• Payment Date → Date (date-only posting information).

Task 2 — Boundary practice

• Code[20]
  • Valid: LN-2026-0001
  • Invalid: LOAN-2026-0001-EXTRA (more than 20 chars)
• Text[100]
  • Valid: First disbursement linked to contract amendment.
  • Invalid: a paragraph beyond 100 chars
• Decimal
  • Valid: 15250.75
  • Invalid: 15,250.75 USD (not a pure decimal value)

Task 3 — Variable scope cleanup

Expected answer pattern:

• Keep only shared state as globals.
• Move temporary calculation variables (InterestAmount, NetAmount) to local procedure var blocks.
• Keep procedure parameters strongly typed instead of relying on globals.

Task 4 — Consistent identifier typing

Expected answer pattern:

• Use Code[20] for Loan No. in table fields, page bindings, report columns, and codeunit procedure parameters.
• Do not mix Text for the same identifier across objects.

Task 5 — Validation guard

Example guard:

if "Principal Amount" <= 0 then
    Error('Principal Amount must be greater than zero.');
if "Interest Amount" < 0 then
    Error('Interest Amount cannot be negative.');

Task 6 — Try it yourself

Sample answer:

• Field: External Reference
• Recommended type: Code[35] if it is a compact external identifier from another system.
• Use Text[100] only if free-form human notes are expected.