Question

嗨，我正在处理下图graph model of the current scenario

我正在从学校顶点遍历到主题，游戏和爱好顶点

所以我写了下面的查询，向我提供了所有学生的详细信息

g.V().hasLabel("school").as('school').out().hasLabel('class').out().hasLabel('student')
.project('student_name','student_details').by('name').by(project('student_description',"reads","plays","havehobbies")
.by('description')
.by(__.outE('reads').inV().values('subject_name').limit(5).dedup().fold())
.by(__.outE("plays").inV().values('game_name').limit(5).dedup().fold())
.by(__.outE('have_hobby').inV().values('hobby_name').dedup().limit(5).fold()).dedup().fold()).dedup()

输出：

[
{
            "student_name": "santhosh kurnapally",
            "student_details": [
                {
                    "student_description": "very good student with high IQ",
                    "reads": [
                        "maths",
                        "science",
                        "social"
                    ],
                    "plays": [
                        "cricket",
                        "football"
                    ],
                    "havehobbies": [
                        "news paper",
                        "tv watching",
                        "cycling"
                    ]
                }
            ]
        },
        {
            "student_name": "santhosh kurnapally",
            "student_details": [
               {
                    "student_description": "very bad student with low IQ",
                    "reads": [
                        "maths",
                        "science"
                    ],
                    "plays": [
                        "cricket",
                        "football"
                    ],
                    "havehobbies": [
                        "news paper",
                        "tv watching"
                    ]
                }
            ]
        },
        {
            "student_name": "neerja goswami",
            "student_details": [
               {
                    "student_description": "very good student with very high IQ",
                    "reads": [
                        "maths",
                        "science",
            "english"
                    ],
                    "plays": [
                        "throw ball",
                        "carroms"
                    ],
                    "havehobbies": [
                        "news paper",
                        "quilling"
                    ]
                }
            ]
        }
]

与上面的输出一样，“ student_name”正在重复，并且希望按“ student_name”进行分组


g.V().hasLabel("school").as('school').out().hasLabel('class').out().hasLabel('student')
.project('student_name','student_details').by('name').by(project('student_description',"reads","plays","havehobbies")
.by('description')
.by(__.outE('reads').inV().values('subject_name').limit(5).dedup().fold())
.by(__.outE("plays").inV().values('game_name').limit(5).dedup().fold())
.by(__.outE('have_hobby').inV().values('hobby_name').dedup().limit(5).fold()).dedup().fold()).dedup()
.group().by('student_name')

但上面的Query抛出如下错误


ActivityId : 6fa77108-39e3-4f77-ba09-2a2e6ca80d9a
ExceptionType : GraphCompileException
ExceptionMessage :
        Gremlin Query Compilation Error: Column reference R_17["student_name"] cannot be located in the raw records in the current execution pipeline.

请让我知道如何达到上述要求或达到上述要求的任何其他选择一个可以是“我可以在学生顶点上分组，然后稍后进行投影”

在这种情况下，我的输出可以如下

[
{
            "santhosh kurnapally": [
                {
                    "student_description": ["very good student with high IQ","very bad student with low IQ"]
                    "reads": [
                        "maths",
                        "science",
                        "social"
                    ],
                    "plays": [
                        "cricket",
                        "football"
                    ],
                    "havehobbies": [
                        "news paper",
                        "tv watching",
                        "cycling"
                    ]
                }
            ]
        },
        {
            "neerja goswami": [
               {
                    "student_description": ["very good student with very high IQ"],
                    "reads": [
                        "maths",
                        "science",
            "english"
                    ],
                    "plays": [
                        "throw ball",
                        "carroms"
                    ],
                    "havehobbies": [
                        "news paper",
                        "quilling"
                    ]
                }
            ]
        }
]

注意：输出结果可能不准确，但关键点是根据投影值进行分组，或者对分组后的顶点（或按其他方式进行分组）或其他任何替代方法进行遍历，并对其进行遍历。

请让我知道与此相同或任何其他替代方法查询的可能性

Answer 1

您应该使用select步骤

g.V().hasLabel('School').as('school').
  out().hasLabel('Class').out().
  hasLabel('Student').
  project('student_name', 'student_details').
    by('name').
    by(project('student_description', 'reads', 'plays', 'havehobbies').
        by('description').
        by(__.outE('reads').inV().
          values('subject_name').limit(5).dedup().
          fold()).
        by(__.outE('plays').inV().values('game_name').
          limit(5).dedup().fold()).
        by(__.outE('have_hobby').inV().values('hobby_name').
          dedup().limit(5).fold()).
      dedup().fold()).
  dedup().
  group().
    by(select('student_name'))

示例：https://gremlify.com/vfnvlkfvybc

通过不使用cosmos DB gremlin API的预计值进行分组

1 个答案: