Using CONNECT BY NOCYCLE and CONNECT_BY_ISCYCLE
(Doc ID 1404713.1)
Last updated on JANUARY 30, 2022
Applies to:
Oracle Database - Standard Edition - Version 10.1.0.2 and laterOracle Database - Personal Edition - Version 10.1.0.2 and later
Oracle Database - Enterprise Edition - Version 10.1.0.2 and later
Oracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Information in this document applies to any platform.
Purpose
A hierarchical SELECT statement (using CONNECT BY) can be a powerful way to query hierarchical data. Since version 10g, hierarchical SELECT statements have had support for cyclic data by using NOCYCLE as well as the CONNECT_BY_ISCYCLE pseudocolumn. But the use of this feature can be difficult to understand and can produce surprising results. This document will demonstrate how the feature works with a few simple examples.
Scope
This document is directed at application developers who wish to better understand how to use CONNECT BY NOCYCLE.
Details
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In this Document
| Purpose |
| Scope |
| Details |
| Example 1 (Cyclic Tree) |
| Example 2 (Directed Cyclic Graph) |
| Summary |
| NOCYCLE |
| PRIOR |
| CONNECT_BY_ISCYCLE |