NB-076
22 lines
870 B
Markdown
22 lines
870 B
Markdown
# 23-select-condition — SELECT Condition Simulation
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## 电信业务场景
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客户合同检索。使用索引文件模拟SELECT条件检索，通过START+READ NEXT实现条件匹配和范围查询。
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## Purpose
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Simulates SQL SELECT with WHERE conditions using GnuCOBOL INDEXED files and START/READ NEXT operations.
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## Test Coverage
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1. **Single record by key** — READ with KEY IS (exact match WHERE)
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2. **Range query** — START with NOT LESS THAN, loop with upper bound check
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3. **Zero results** — Key not found, INVALID KEY handling
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4. **Greater-than query** — START with GREATER THAN, read all following records
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## Key Techniques
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- INDEXED file ORGANIZATION with DYNAMIC access
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- START for positioning (KEY IS GREATER THAN / NOT LESS THAN)
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- READ NEXT for sequential traversal
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- FILE STATUS checking
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- INVALID KEY / NOT INVALID KEY for conditional handling
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