Editing Assumptions and Dependencies

<span id="assumptions-dependencies-and-constraints"></span>
= Assumptions, Dependencies, and Constraints =

{|
!width="23%"| Field
!width="76%"| Value
|-
| Document ID
| PGCBL-SAD-002
|-
| Document Type
| Assumptions, Dependencies, and Constraints Register
|-
| System
| pgcobol — Prime Numbers Application v1.0
|-
| Version
| 1.0
|-
| Status
| Draft — requires stakeholder confirmation
|-
| Owner
| Lead Developer
|-
| Author
| [reverse-engineered from source artifacts]
|-
| Created
| 2026-03-17
|-
| Last modified
| 2026-03-17
|-
| Classification
| Internal
|-
| Parent document
| PGCBL-BRD-001
|}

<span id="version-history"></span>
== Version History ==

{|
!width="13%"| Version
!width="17%"| Date
!width="11%"| Author
!width="11%"| Status
!width="44%"| Change Summary
|-
| 0.1
| 2026-03-17
| —
| Draft
| Derived from source analysis
|}


-----

<span id="table-of-contents"></span>
== Table of Contents ==

# [[#1-purpose|Purpose]]
# [[#2-how-to-use-this-register|How to Use This Register]]
# [[#3-assumptions|Assumptions]]
# [[#4-dependencies|Dependencies]]
# [[#5-constraints|Constraints]]
# [[#6-risk-summary|Risk Summary]]
# [[#7-open-issues|Open Issues]]


-----

<span id="purpose"></span>
== 1. Purpose ==

This register captures every assumption made during the design, every dependency the system relies on, and every constraint that limits the design space. It exists so that:

* If an assumption turns out to be wrong, the impact on the design can be assessed quickly.
* If a dependency is unavailable, the team knows what is blocked.
* Constraints are documented with their source, so they can be challenged if the source changes.

Items marked '''[UNCONFIRMED]''' were inferred from source code analysis and have not been verified with a stakeholder.


-----

<span id="how-to-use-this-register"></span>
== 2. How to Use This Register ==

<span id="best-practice-generic"></span>
=== Best practice — generic ===

An assumption is something the team '''believes to be true''' but has not verified. Every assumption carries a risk: if the assumption is wrong, some part of the design or implementation will fail. Good practice is to:

# State the assumption precisely (not vaguely).
# Identify who should confirm or refute it.
# Assign a risk severity if the assumption is wrong.
# Track confirmation explicitly — an unconfirmed assumption is a risk item.

A dependency is something '''external to the system''' that must exist or be in a known state for the system to function. Dependencies are not assumptions — they are facts that must be managed.

A constraint is a '''limit imposed from outside''' the design team (a regulation, a platform choice, a budget) that restricts what solutions are possible.

<span id="severity-scale"></span>
=== Severity scale ===

{|
!width="50%"| Severity
!width="50%"| Meaning
|-
| High
| If wrong/unmet, the system cannot run or produces incorrect results
|-
| Medium
| If wrong/unmet, a feature is degraded or a workaround is needed
|-
| Low
| If wrong/unmet, a minor inconvenience; easily remediated
|}


-----

<span id="assumptions"></span>
== 3. Assumptions ==

{|
!width="9%"| ID
!width="15%"| Assumption
!width="18%"| Confirmed by
!width="21%"| Confirmed date
!width="25%"| Severity if wrong
!width="10%"| Status
|-
| A-01
| Prime 2 is manually inserted into the database before the first generation run. The algorithm starts at candidate 3 and immediately calls <code>next-divider</code> (ident=2), which requires a row with ident=2 to exist.
| [UNCONFIRMED]
| —
| High
| Open
|-
| A-02
| The <code>primes</code> table is empty at the start of a fresh generation run. No de-duplication logic exists in the INSERT path; re-running generation will insert duplicate primes.
| [UNCONFIRMED]
| —
| High
| Open
|-
| A-03
| The <code>asc_ident</code> sequence is reset to 1 before each generation run (achieved by running <code>reset-primes.sql</code>). If the sequence is not reset, the ident values used by the divider lookup will be wrong.
| [UNCONFIRMED]
| —
| High
| Open
|-
| A-04
| The working directory at runtime is writable by the process owner, so <code>primes.prt</code> can be created.
| [UNCONFIRMED]
| —
| High
| Open
|-
| A-05
| GnuCOBOL 4.0 and the GixSQL pre-processor are installed and on PATH before compilation.
| [UNCONFIRMED]
| —
| High
| Open
|-
| A-06
| PostgreSQL is running on <code>localhost:5432</code> when any program that calls <code>primes.cbl</code> is executed.
| [UNCONFIRMED]
| —
| High
| Open
|-
| A-07
| The PostgreSQL schema <code>primes</code> and the user <code>primes_user</code> exist and have been granted the necessary privileges before first run.
| [UNCONFIRMED]
| —
| High
| Open
|-
| A-08
| The system is run by a single operator at a time; no concurrent execution is expected.
| [UNCONFIRMED]
| —
| Medium
| Open
|-
| A-09
| The 132-character print record width matches the target printer or viewer.
| [UNCONFIRMED]
| —
| Low
| Open
|-
| A-10
| <code>primes_cbsql.out</code> (the pre-compiler listing) is a historical artefact of an earlier version of <code>primes.cbl</code> and the <code>primesdb</code> connection alias it references is no longer active.
| [UNCONFIRMED]
| —
| Medium
| Open
|}


-----

<span id="dependencies"></span>
== 4. Dependencies ==

{|
!width="12%"| ID
!width="21%"| Dependency
!width="10%"| Type
!width="29%"| Version required
!width="12%"| Owner
!width="14%"| Status
|-
| DEP-01
| GnuCOBOL compiler
| Build-time
| 4.0 or later
| Developer environment
| Must be installed
|-
| DEP-02
| GixSQL pre-processor
| Build-time
| Compatible with GnuCOBOL 4.0
| Developer environment
| Must be installed
|-
| DEP-03
| PostgreSQL server
| Runtime
| 11 or later
| DBA
| Must be running on localhost:5432
|-
| DEP-04
| <code>primes</code> database and schema
| Runtime
| —
| DBA
| Must exist; created by <code>primes_schema.sql</code>
|-
| DEP-05
| <code>primes_user</code> account
| Runtime
| —
| DBA
| Must exist with INSERT, SELECT privileges on <code>primes.primes</code>
|-
| DEP-06
| Writable working directory
| Runtime
| —
| OS / operator
| Needed for <code>primes.prt</code>
|-
| DEP-07
| <code>reset-primes.sql</code> executed before each generation run
| Operational
| —
| Operator
| Required for idempotent generation
|-
| DEP-08
| Prime 2 seeded in <code>primes.primes</code> before first generation
| Operational
| —
| Operator
| Required for divider lookup to work from candidate 3
|}


-----

<span id="constraints"></span>
== 5. Constraints ==

{|
!width="20%"| ID
!width="34%"| Constraint
!width="22%"| Source
!width="22%"| Impact
|-
| C-01
| Target runtime is Linux only. <code>SPECIAL-NAMES. CONSOLE IS scherm</code> is platform-specific.
| GnuCOBOL platform support
| Cannot run on Windows or mainframe without porting
|-
| C-02
| Database must be PostgreSQL. The connection string prefix <code>pgsql://</code> and GixSQL dialect are PostgreSQL-specific.
| GixSQL driver
| Not portable to DB2, Oracle, or SQL Server without code changes
|-
| C-03
| Upper generation limit is hard-coded at 999,999,999.
| Source code <code>primesgen.cbl</code> line 91
| Cannot be changed without recompilation
|-
| C-04
| Database credentials are hard-coded in <code>primes.cbl</code> WORKING-STORAGE.
| Source code; technical debt
| Credential rotation requires recompilation and redeployment
|-
| C-05
| Print record width is fixed at 132 characters.
| <code>primesui.cbl</code> FD and table layout
| Report format cannot be changed without recompiling <code>primesui</code>
|-
| C-06
| The two operational modes (generate / report) are mutually exclusive per invocation.
| <code>primesmain.cbl</code> EVALUATE structure
| Cannot generate and report in the same run
|-
| C-07
| GnuCOBOL 4.0-early-dev was used; behaviour may differ from stable GnuCOBOL 3.x.
| Compiler listing header
| Compatibility with stable GnuCOBOL releases unverified
|}


-----

<span id="risk-summary"></span>
== 6. Risk Summary ==

Items with High severity that are still unconfirmed represent the greatest project risk:

{|
!width="33%"| Risk
!width="33%"| Assumptions involved
!width="33%"| Recommended action
|-
| Generation produces wrong results or crashes on fresh DB
| A-01, A-02, A-03
| Write a pre-run setup script and document it as a mandatory step
|-
| Program fails silently at runtime due to missing infrastructure
| A-04, A-05, A-06, A-07
| Add pre-flight checks to <code>primesmain</code> (file/DB accessibility tests)
|-
| Pre-compiler listing alias mismatch causes disconnect failure
| A-10
| Inspect current <code>primes.cbl</code> disconnect path and confirm alias is <code>primes</code>
|}


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<span id="open-issues"></span>
== 7. Open Issues ==

{|
!width="18%"| ID
!width="18%"| Issue
!width="18%"| Owner
!width="21%"| Target
!width="21%"| Status
|-
| OI-01
| All assumptions are unconfirmed. A stakeholder/developer review session is needed to confirm or correct each one.
| Lead Dev
| —
| Open
|-
| OI-02
| No pre-run setup script exists. DEP-07 and DEP-08 are manual steps with no enforcement.
| Developer
| —
| Open
|}
<hr/>
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