Editing Naming and Coding Standards (section)

== 4. Data Naming Conventions ==

<span id="general-rules"></span>
=== 4.1 General rules ===

{|
!width="50%"| Rule
!width="50%"| Rationale
|-
| Use hyphens as word separators: <code>test-number</code>, not <code>testNumber</code> or <code>test_number</code>
| COBOL convention; underscores are non-standard in some compilers
|-
| Maximum name length: 30 characters (COBOL 85 limit)
| Portability
|-
| Names must be meaningful: no single-letter names except loop indexes
| Readability
|-
| Avoid COBOL reserved words and common abbreviations that conflict (e.g. <code>LENGTH</code>, <code>SPACE</code>)
| Prevents ambiguity
|-
| Prefix 88-level condition names with the purpose they test, not the field name
| <code>dal-method-ok</code> not <code>dal-result-zero</code>
|}

<span id="level-number-conventions"></span>
=== 4.2 Level number conventions ===

{|
!width="50%"| Level
!width="50%"| Use
|-
| 01
| Group items, independent items, copybook roots
|-
| 03, 05, 07
| Subordinate group and elementary items (use odd numbers: 01, 03, 05, 07 …)
|-
| 66
| RENAMES clause (use sparingly)
|-
| 77
| Independent elementary items (prefer 01 unless 77 is clearly appropriate)
|-
| 88
| Condition names; always immediately under the field they qualify
|}

'''Rule:''' Use odd-numbered levels (01, 03, 05, 07, 09) to allow insertion of intermediate levels without renumbering. Never use even levels in new code.

<span id="naming-prefixes-for-scope"></span>
=== 4.3 Naming prefixes for scope ===

{|
!width="33%"| Prefix
!width="33%"| Meaning
!width="33%"| Example
|-
| <code>r-</code>
| Record / row field (fetched from DB)
| <code>r-ident</code>, <code>r-prime</code>
|-
| <code>u-</code>
| UI-layer field (in primes-ui block)
| <code>u-sequence</code>, <code>u-number</code>
|-
| <code>t-</code>
| Table cell / temporary print field
| <code>t-ident</code>, <code>t-prime</code>
|-
| <code>f-</code>
| Formatted / print-ready field
| <code>f-page-number</code>
|-
| <code>w-</code>
| Work field (local computation)
| <code>w-remainder</code>
|}

<span id="picture-clause-conventions"></span>
=== 4.4 Picture clause conventions ===

{|
!width="33%"| Type
!width="33%"| Preferred PICTURE
!width="33%"| Notes
|-
| Positive integer, display
| <code>9(n)</code>
| n ≤ 9 for standard arithmetic
|-
| Signed integer, display
| <code>S9(n)</code>
| Use S prefix for fields that can go negative or are SQL host variables
|-
| Packed decimal
| <code>S9(n) COMP-3</code>
| For high-volume arithmetic and SQL host variables
|-
| Binary integer
| <code>S9(n) COMP-5</code>
| For SQLCA fields and counters needing maximum performance
|-
| Fixed decimal
| <code>9(n)V9(m)</code>
| V = implied decimal point; no actual decimal character stored
|-
| Alphanumeric
| <code>X(n)</code>
| For text, method verbs, messages
|-
| Edited numeric (print)
| <code>Z(n)9</code> or <code>Z(n)</code>
| For zero-suppressed print output only; never used in arithmetic
|-
| Boolean flag
| <code>9(1)</code> with 88-levels
| e.g. <code>PIC 9 VALUE 1. 88 new-page VALUE 1.</code>
|}

<span id="level-condition-names"></span>
=== 4.5 88-level condition names ===

* Must be named for what is '''true''' when the condition fires, not for the value: <code>session-method-ok</code> not <code>result-is-zero</code>.
* Result-code 88-levels must cover all meaningful values; add a <code>88 invalid-method VALUE &quot;bad&quot;</code> sentinel.
* Multiple conditions for the same field must have non-overlapping VALUES.

<span id="copybook-field-naming"></span>
=== 4.6 Copybook field naming ===

* Fields in a copybook must be globally unique across all copybooks in the project (COBOL does not namespace copybooks).
* Prefix copybook fields with the copybook’s logical name: <code>dal-methods</code>, <code>ui-method-result</code>, <code>session-result</code>.


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<span id="paragraph-naming-conventions"></span>