mongodb - 如何在 MongoDB 3.4.0 中使用 $graphLookup 创建 View ？

Question

我正在管道中使用 $graphLookup 创建 View 但失败了。有人有什么想法吗？

$cmd:

{
  "create": "employee.view.list",
  "viewOn": "employee",
  "pipeline": [
    {
      "$graphLookup": {
        "from": "employee.view.list",
        "connectToField": "_id",
        "startWith": "$supervisor",
        "connectFromField": "supervisor",
        "as": "supervisors",
        "maxDepth": 10
      }
    }
  ]
}

错误

View cycle detected: test_sw-aggregation-test.employee.view.list => test_sw-aggregation-test.employee.view.list

Answer 1

您收到此错误是因为您正在创建与要对其文档执行 $graphLookup 的集契约(Contract)名的 View 。

此外，employee.view.list 不是预定义的 View ，在这种情况下，您会收到如下所示的错误消息:

{
    "ok" : 0,
    "errmsg" : "a view 'employee.view.list' already exists",
    "code" : 48,
    "codeName" : "NamespaceExists"
}