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Recursive Traversal Using CTE
In this example, we create a file system with a tree structure, and want to query all "undeleted" files. A file is considered as "deleted", if it's marked as "deleted" (a bool field), or any of its parents is marked as "deleted".
Given the following tree structure:
a/
├─ b/
│ ├─ ba
│ ├─ bb
│ └─ bc (deleted)
├─ c/ (deleted)
│ ├─ ca
│ └─ cb
└─ d (deleted)
Query "undeleted" files should return the following structure:
a/
└─ b/
├─ ba
└─ bb
As you can see, in order to check if "cb" (or "ca") is "deleted", we need to "look behind" recursively until we find a "deleted" parent, or reach the root ("a").
Generate Assets
go generate ./...
Run Example
go test