Editing Data dictionary (section)

== 3. Copybook: primes-dal.cpy ==

'''Control block for the DAL (business-logic → data-access) tier.'''

{|
!width="20%"| Name
!width="20%"| Level
!width="20%"| Picture
!width="20%"| Usage
!width="20%"| Description
|-
| <code>primes-dal</code>
| 01
| —
| —
| Root of DAL control block; passed as linkage to primes
|-
| <code>dal-methods</code>
| 03
| X(32)
| DISPLAY
| Operation verb set by caller
|-
| — <code>next-prime</code>
| 88
| —
| —
| VALUE “next-prime” — fetch next row from cursor
|-
| — <code>next-divider</code>
| 88
| —
| —
| VALUE “next-divider” — select divider by ident
|-
| — <code>write-prime</code>
| 88
| —
| —
| VALUE “write” — insert prime into table
|-
| — <code>db-cursor</code>
| 88
| —
| —
| VALUE “cursor” — start transaction and open cursor
|-
| — <code>db-connect</code>
| 88
| —
| —
| VALUE “connect” — connect to PostgreSQL
|-
| — <code>db-disconnect</code>
| 88
| —
| —
| VALUE “disconnect” — disconnect from PostgreSQL
|-
| — <code>invalid-method</code>
| 88
| —
| —
| VALUE “bad” — sentinel for bad dispatch
|-
| <code>primes-data</code>
| 03
| —
| —
| One-row data payload
|-
| <code>primes-sequence</code>
| 05
| 9(9)
| DISPLAY
| Sequence / ident of the current prime row
|-
| <code>prime-number</code>
| 05
| 9(9)
| DISPLAY
| Value of the current prime
|-
| <code>dal-result</code>
| 03
| 9(2)
| DISPLAY
| Result code written back by primes; initial value ZERO
|-
| — <code>dal-method-ok</code>
| 88
| —
| —
| VALUE 0 — operation succeeded
|-
| — <code>dal-method-nok</code>
| 88
| —
| —
| VALUE 1 — operation failed
|-
| — <code>dal-method-eof</code>
| 88
| —
| —
| VALUE 99 — cursor exhausted
|}


-----

<span id="copybook-primes-ui.cpy"></span>