Question

所以我正在尝试使用CosmosDb，并希望将Gremlin API用于Vertex和Edge查询。我有许多实体，它们之间有多个边缘连接，如“知道”，“信任”，“喜欢”等等。

但是我希望将复杂的文档作为顶点，所以不要使用具有许多属性的文本查询的gremlin语法（这看起来非常麻烦）我使用documentDB API插入了文档。问题是一旦添加了一个文档（它正确地返回并在SQL查询中显示）我不能在没有出现错误的情况下进行任何g.V（）调用：

System.InvalidCastException: Invalid cast from 'System.String' to 'Newtonsoft.Json.Linq.JObject'.

我也无法为这些顶点添加边。

所以我的问题是，我是否试图以错误的方式做到这一点？我的复杂对象应该保存在一个单独的集合中，然后将它们的ID镜像到新集合中的顶点吗？

您是否可以在同一个集合中使用Gremlin API和Document API？

感谢您的任何建议。

理查德

Oliver的更新

这是使用documentdb库创建的简单测试文档，然后在我从数据资源管理器中的c执行SQL Select *时显示：

 {
        "id": "beea4756-2a25-4e2e-a7d9-457ad03dd56d",
        "title": "Test item",
        "description": "Test description",
        "purchaseUrl": "http://www.test.co.uk",
        "imageUrls": [
            "http://www.test.com",
            "http://www.test2.com"
        ],
        "label": "item",
        "created": "2017-10-09T12:41:49.0201322Z",
        "modified": "2017-10-09T12:41:49.0203021Z",
        "createdById": "TestUserId",
        "modifiedById": "TestUserId",
        "_rid": "jXNCAKbsIQABAAAAAAAAAA==",
        "_self": "dbs/jXNCAA==/colls/jXNCAKbsIQA=/docs/jXNCAKbsIQABAAAAAAAAAA==/",
        "_etag": "\"00000629-0000-0000-0000-59db6e8d0000\"",
        "_attachments": "attachments/",
        "_ts": 1507552909
    }

这是我在Azure门户网站的图形资源管理器中使用g.V（）时遇到的错误（或者当我在代码中尝试任何gremlin查询或边缘创建时）：

    System.InvalidCastException: Invalid cast from 'System.String' to 'Newtonsoft.Json.Linq.JObject'.
   at System.Convert.DefaultToType(IConvertible value, Type targetType, IFormatProvider provider)
   at Newtonsoft.Json.Linq.Extensions.Convert[T,U](T token)
   at Newtonsoft.Json.Linq.Extensions.<Convert>d__14`2.MoveNext()
   at Microsoft.Azure.Graphs.Runtime.VertexPropertyField.Replace(JProperty jproperty)
   at Microsoft.Azure.Graphs.Runtime.VertexField..ctor(GraphCommand graphCommand, JObject vertexObject)
   at Microsoft.Azure.Graphs.Common.VertexObjectCache.AddOrUpdateVertexField(VertexCompositeKey vertexKey, JObject vertexObject)
   at Microsoft.Azure.Graphs.Runtime.DocumentDBRuntime.<GetVertices>d__1.MoveNext()
   at Microsoft.Azure.Graphs.Runtime.Operators.FetchNodeOperator.<ComputeNextRecordAsync>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Graphs.Runtime.Operators.GraphExecutionOperator.<NextAsync>d__9.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Graphs.Runtime.Operators.ProjectOperator.<ComputeNextRecordAsync>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Graphs.Runtime.Operators.GraphExecutionOperator.<NextAsync>d__9.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Graphs.GraphTraversal.GraphTraversalIterator.<CurrentOperatorNextAsync>d__17.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Graphs.GraphTraversal.GraphTraversalIterator.<MoveNextAsync>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Graphs.GraphTraversal.<MoveNextAsync>d__17.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Graphs.GremlinDocumentQuery`1.<ExecuteNextAsync>d__15`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Graphs.GremlinDocumentQuery`1.<ExecuteNextAsync>d__14.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.Portal.PlatformProxy.Graph.Controllers.GremlinQueriesController.<SubmitQueryAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.Portal.PlatformProxy.Graph.Controllers.GremlinQueriesController.<Post>d__0.MoveNext()

Answer 1

可以在同一个集合中混合和匹配Graph和Document API。但是，只有以GraphSON格式插入图形文档所需的顶点和边时，它才有效。如果您测试为边和顶点运行一些gremlin插入，然后使用Document API检查集合中文档的格式，您将看到预期格式的样子。

在我的工作中，我们构建了一个自定义ORM，它使用C＃POCO表示我们的顶点和边缘，并在使用Document API进行实际插入之前使用反射构建适当的结构。通过这种方式，您可以获得两全其美的效果。

您在此处提到的另一个选项是，根据您正在构建的应用程序的性质，有一个用于表示纯关系的集合和另一个用于存储实际文档的集合。肯定会有额外的网络电话填写实际文件以及错过SPROC等形式的交易。

将文档和图形存储在DocumentDb的同一集合中

1 个答案: