Editing Primes Software Specification (section)

== 3. Data Dictionary ==

<span id="working-storage-fields"></span>
=== 3.1 Working Storage Fields ===

{|
!width="25%"| Field
!width="25%"| PIC
!width="25%"| COBOL Type
!width="25%"| Description
|-
| <code>DATASRC</code>
| <code>X(64)</code>
| Alphanumeric
| PostgreSQL connection string
|-
| <code>DBUSR</code>
| <code>X(64)</code>
| Alphanumeric
| Database login username
|-
| <code>DBPWD</code>
| <code>X(64)</code>
| Alphanumeric
| Database login password
|-
| <code>CUR-STEP</code>
| <code>X(16)</code>
| Alphanumeric
| Current processing step label
|-
| <code>prime-count</code>
| <code>9(9)</code>
| Numeric
| Count of primes (declared; populated by driver)
|-
| <code>prime_seq</code>
| <code>9(9)</code>
| Numeric
| Prime sequence number (declared; populated by driver)
|-
| <code>divider</code>
| <code>9(9)</code>
| Numeric
| Trial divider working field
|}

<span id="group-primes-row-database-fetch-buffer"></span>
=== 3.2 Group: <code>primes-row</code> — Database Fetch Buffer ===

{|
!width="25%"| Field
!width="25%"| PIC
!width="25%"| COBOL Type
!width="25%"| Description
|-
| <code>r-ident</code>
| <code>9(9) COMP-3</code>
| Packed decimal
| Row identity key fetched from cursor
|-
| <code>r-prime</code>
| <code>9(9) COMP-3</code>
| Packed decimal
| Prime value fetched from cursor
|}

<span id="group-primes-primality-test-working-storage"></span>
=== 3.3 Group: <code>primes</code> — Primality Test Working Storage ===

{|
!width="33%"| Field
!width="33%"| PIC / Value
!width="33%"| Description
|-
| <code>primes-result</code>
| <code>9(2)</code>
| Status code: <code>1</code>=init ok · <code>2</code>=first divider ok · <code>3</code>=next divider ok
|-
| <code>88 init-primes-ok</code>
| value <code>1</code>
| Condition name: initialisation succeeded
|-
| <code>88 first-divider-ok</code>
| value <code>2</code>
| Condition name: first trial divisor retrieved
|-
| <code>88 next-divider-ok</code>
| value <code>3</code>
| Condition name: subsequent trial divisor retrieved
|-
| <code>test-number</code>
| <code>9(9)</code>
| Candidate number under primality test
|-
| <code>test-number-sqr</code>
| <code>9(9)v9(9)</code>
| Square root of <code>test-number</code> — upper bound for divisor loop
|-
| <code>test-divider</code>
| <code>9(9)</code>
| Current prime divisor retrieved from DB
|-
| <code>test-rest</code>
| <code>9(9)v9(9)</code>
| Remainder of <code>test-number ÷ test-divider</code>
|-
| <code>old-test-number</code>
| <code>9(9)</code>
| Previous candidate number
|-
| <code>old-ident</code>
| <code>9(9)</code>
| Row identity of the last retrieved divisor
|-
| <code>new-ident</code>
| <code>9(9)</code>
| Row identity of the next divisor (<code>old-ident + 1</code>)
|}

<span id="copybook-references"></span>
=== 3.4 Copybook References ===

{|
!width="50%"| Copybook
!width="50%"| Contents
|-
| <code>primes-table</code>
| COBOL record layout mirroring the <code>primes</code> DB table
|-
| <code>SQLCA</code>
| Standard SQL Communication Area (<code>SQLCODE</code>, <code>SQLERRM</code>, etc.)
|-
| <code>primes-ui</code>
| Data structure for <code>primesui</code> subprogram (messages, program name, methods)
|-
| <code>primes-dal</code>
| DAL linkage interface — method flags and <code>dal-result</code> return code
|}

<span id="prepared-sql-statements"></span>
=== 3.5 Prepared SQL Statements ===

{|
!width="33%"| Ref
!width="33%"| SQL Text
!width="33%"| Used in
|-
| <code>SQ0001</code>
| <code>SELECT * FROM primes</code>
| Cursor declaration (s01-cursor)
|-
| <code>SQ0002</code>
| <code>SELECT prime FROM primes WHERE ident = $1</code>
| r81-get-next-divider
|-
| <code>SQ0003</code>
| <code>INSERT INTO primes (prime) VALUES ($1)</code>
| r83-write-prime
|-
| <code>SQ0004</code>
| <code>INSERT INTO primes (prime) VALUES (2)</code>
| r90-generate-primes (seed)
|-
| <code>SQ0005</code>
| <code>START TRANSACTION</code>
| s01-cursor
|}

<span id="database-table-primes.primes"></span>
=== 3.6 Database Table: <code>primes.primes</code> ===

{|
!width="33%"| Column
!width="33%"| Type
!width="33%"| Description
|-
| <code>ident</code>
| INTEGER (serial / sequence)
| Auto-generated row identity / primary key
|-
| <code>prime</code>
| INTEGER
| The prime number value stored in this row
|}


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<span id="flow-diagrams"></span>