如何在 Neo4j 中获取 json 形式的节点和关系的分层列表

Question

我有一个 Neo4j 数据库，其中存储用户数据和它们之间的关系，最终用户将通过移动应用程序与这些数据进行交互（应用程序位于 Flutter 中，我们在两者之间使用 Nestjs Neo4j 连接器）。现在我们必须启用对数据的离线访问。所以我们的想法是从 neo4j 将用户数据导出为 json 并在离线时使用它，当设备上线时我们将对数据库进行更改。我在获取 json 数据时遇到一些问题

这是我想要做的一个粗略示例

用于创建这些节点的 cypher 命令

CREATE (c:Computer {name: 'Andy',uid:'123'})
CREATE (d1:Drive {name: 'Drive1',capacity:"2gb",uid:'223'})
CREATE (d2:Drive {name: 'Drive2',capacity:"4gb",uid:'233'})
CREATE (f1:Folder {name: 'desktop',type:"special",uid:'323'})
CREATE (f2:Folder {name: 'mydocuments',type:"special",uid:'333'})
CREATE (f3:Folder {name: 'myprojects',type:"normal",uid:'343'})

CREATE (t1:File {name: 'text1',type:"txt",size:"1kb",uid:'423'})
CREATE (t2:File {name: 'text2',type:"txt",size:"1.5kb",uid:'433'})
CREATE (t3:File {name: 'text3',type:"txt",size:"2kb",uid:'443'})

CREATE (do1:File {name: 'doc1',type:"doc",size:"1mb",uid:'523'})
CREATE (do2:File {name: 'doc2',type:"doc",size:"1.5mb",uid:'533'})
CREATE (do3:File {name: 'doc3',type:"doc",size:"2mb",uid:'543'})


CREATE (c)-[r1:PARTITION{during: 'osinstall'}]->(d1)
CREATE (c)-[r2:PARTITION{during: 'setup'}]->(d2)

CREATE (d1)-[r3:AutoCreated{during: 'osinstall',type:"folder"}]->(f1)
CREATE (d1)-[r4:AutoCreated{during: 'osinstall',type:"folder"}]->(f2)
CREATE (f1)-[r5:Shortcut{type:"folder"}]->(c)
CREATE (f2)-[r6:Shortcut{type:"folder"}]->(c)
CREATE (d2)-[r7:UserCreated{type:"folder"}]->(f3)

CREATE (d2)-[r8:UserCreated{type:"file"}]->(t1)
CREATE (d2)-[r9:UserCreated{type:"file"}]->(t2)
CREATE (f3)-[r10:UserCreated{type:"file"}]->(t3)
CREATE (f3)-[r11:UserCreated{type:"file"}]->(do1)
CREATE (d2)-[r12:UserCreated{type:"file"}]->(do2)
CREATE (do2)-[r13:Shortcut{type:"file"}]->(f1)
CREATE (f3)-[r14:Shortcut{type:"folder"}]->(f1)
CREATE (f1)-[r15:UserCreated{type:"file"}]->(do3)
CREATE (do3)-[r16:Shortcut{type:"file"}]->(f3)

CREATE (c1:Computer {name: 'Randy',uid:'c1-123'})
CREATE (c1d1:Drive {name: 'Drive1',capacity:"1gb",uid:'c1-223'})
CREATE (c1t1:File {name: 'text1',type:"txt",size:"1kb",uid:'c1-423'})
CREATE (c1t2:File {name: 'text2',type:"txt",size:"1.5kb",uid:'c1-433'})
CREATE (c1sh1:SharedDrive {name:"SharedDrive",uid:'c1-s1'})

CREATE (c1)-[c1r1:PARTITION{during: 'osinstall'}]->(c1d1)
CREATE (c1d1)-[c1r2:UserCreated{type:"file"}]->(c1t1)
CREATE (c1d1)-[c1r3:UserCreated{type:"file"}]->(c1t2)
CREATE (c1t1)-[c1r4:Share{type:"file"}]->(c1sh1)
CREATE (c1)-[c1r5:SHAREDPARTITION{during: 'osinstall'}]->(c1sh1)
CREATE (c1)-[common:Network]->(c)

我想使用用户 uid 查询根节点（例如 Andy），并以

    {
    "name": "Andy",
    "uid":"123",
    "PARTITION":[
        {
            "name": "Drive1",
            "capacity":"2gb",
            "uid":"223",
            "Folder":[
               { "name": "desktop","type":"special","uid":"323",
               "File":[
                   "... Detail about file doc3 here.."
               ],
               "Shortcut":[
                   "... Detail about file doc2 here.."
               ]
               
               },
               {"name": "mydocuments","type":"special","uid":"333"}
            ]
        },
        {
            "name": "Drive2",
            "capacity":"4gb",
            "uid":"233",
            "Folder":[
               { "name": "myprojects","type":"normal","uid":"343",
                "File":[
                    "...Detail about Files doc1, text3 here..."
                ],
                "Shortcut":[
                    "... Detail about file doc3 here.."
                ]
                
               }
            ],
            "File":[
                "...Detail about Files text1,text2,doc 2 here..."
            ]

        }
    ],
    "Shortcut":[
        {
            "name": "desktop","type":"special","uid":"323"
        },{
            "name": "mydocuments","type":"special","uid":"333"
        }
    ],
    "Network":[
        {
            "name": "Randy",
            "uid":"c1-123",
            "SHAREDPARTITION":["...HERE ONLY NEED THE files and folders from shareddrive other drives should not show up..."]

        }
    ]
}

我想将节点之间的关系添加为键的 格式获取数据以及增值连接到它的节点列表（及其相关属性）并移至下一个。我不知道该怎么做。到目前为止，我已经尝试过

match (n:Computer{uid:"123"})-[r:PARTITION]->(x)
match b=(x)-[*]->(y)
with collect(b) as c
call apoc.convert.toTree(c) yield value
return value

，但这并没有正确返回快捷方式文件路径，即，如果我添加从 doc3（在桌面）到 myproject 的快捷方式，我找不到带有 myproject 快捷方式的文件详细信息，我在两个地方都需要它桌面（在文件下）和myproject（在快捷方式下）文件夹。此外，不会获取共享计算机的详细信息（不得仅获取共享分区的所有驱动器）。除此之外，返回数据不是预期的格式，我必须在获取数据后在应用程序中对其进行处理。

有人可以帮我解决这个问题吗？

我也对 Neo4j Flutter 离线的不同解决方案持开放态度。

Answer 1

您可以从根节点创建连接，然后将它们全部收集在一起。只需确保您正在使用要提取的关系即可。下面的格式与您描述的不完全一样，但最接近您的 json 格式。

match b=(n:Computer{uid:"123"})-[r:PARTITION]->(x:Drive)-[]-(y:Folder)-[]-(z:File) 
match c=(n)-[:Shortcut]-()
match d=(n)-[:Network]-()-[:SHAREDPARTITION]-()
with collect(b) + collect(c) + collect(d) as t
call apoc.convert.toTree(t) yield value
return value

Result:

 {
  "name": "Andy",
  "uid": "123",
  "_type": "Computer",
  "_id": 298,
  "partition": [
    {
      "uid": "233",
      "_type": "Drive",
      "name": "Drive2",
      "_id": 300,
      "partition.during": "setup",
      "capacity": "4gb",
      "usercreated": [
        {
          "uid": "343",
          "shortcut": [
            {
              "uid": "543",
              "size": "2mb",
              "shortcut.type": "file",
              "_type": "File",
              "name": "doc3",
              "_id": 309,
              "type": "doc"
            }
          ],
          "_type": "Folder",
          "name": "myprojects",
          "usercreated": [
            {
              "uid": "443",
              "size": "2kb",
              "_type": "File",
              "name": "text3",
              "_id": 306,
              "type": "txt",
              "usercreated.type": "file"
            },
            {
              "uid": "523",
              "size": "1mb",
              "_type": "File",
              "name": "doc1",
              "_id": 307,
              "type": "doc",
              "usercreated.type": "file"
            }
          ],
          "_id": 303,
          "type": "normal",
          "usercreated.type": "folder"
        }
      ]
    },
    {
      "uid": "223",
      "_type": "Drive",
      "name": "Drive1",
      "_id": 299,
      "partition.during": "osinstall",
      "capacity": "2gb",
      "autocreated": [
        {
          "autocreated.during": "osinstall",
          "autocreated.type": "folder",
          "uid": "323",
          "shortcut": [
            {
              "uid": "533",
              "size": "1.5mb",
              "shortcut.type": "file",
              "_type": "File",
              "name": "doc2",
              "_id": 308,
              "type": "doc"
            }
          ],
          "_type": "Folder",
          "name": "desktop",
          "usercreated": [
            {
              "uid": "543",
              "size": "2mb",
              "_type": "File",
              "name": "doc3",
              "_id": 309,
              "type": "doc",
              "usercreated.type": "file"
            }
          ],
          "_id": 301,
          "type": "special"
        }
      ]
    }
  ],
  "shortcut": [
    {
      "uid": "333",
      "shortcut.type": "folder",
      "_type": "Folder",
      "name": "mydocuments",
      "_id": 302,
      "type": "special"
    },
    {
      "uid": "323",
      "shortcut.type": "folder",
      "_type": "Folder",
      "name": "desktop",
      "_id": 301,
      "type": "special"
    }
  ],
  "network": [
    {
      "_type": "Computer",
      "name": "Randy",
      "uid": "c1-123",
      "_id": 310,
      "sharedpartition": [
        {
          "_type": "SharedDrive",
          "name": "SharedDrive",
          "uid": "c1-s1",
          "_id": 473,
          "sharedpartition.during": "osinstall"
        }
      ]
    }
  ]
}