cobol-java-v3/benchmark-programs/33-mix-1N-diffkeybreak/README.md

33-mix-1N-diffkeybreak — 1:N Matching with Different-Key Break

电信业务场景

线路+类型混合切替。先做线路↔通话类型的关联，再检测通话类型的变化。用于不同通话类型(语音/SMS/数据)的计费切换。

Purpose

Demonstrates 1:N matching pattern where the key break detection uses a different key field than the match key, showing master-to-detail transitions.

Test Coverage

1. 1:N matching — One master (M0001) matched to three details
2. Different-key break — Key break is triggered by master ID change (M0001 -> M0002 -> M0003 -> M0004)
3. Unmatched master ID — Detail with M9999 has no matching master
4. Summary per break — Count and total per master ID group
5. Final break — Last group summary at end of file

Data

• 4 master records (M0001 through M0004) with names, types, amounts
• 10 detail records with master ID references

Key Techniques

• In-memory master table loaded at startup
• Key break on master ID field (different from detail transaction ID)
• Accumulator per break group
• Grand total across all groups
• Unmatched ID detection and reporting