关于JSON的“裂缝陷阱”（数据建模-USS）

当BI工具从 JSON 文件中读取表格数据时，某些情况下也会出现类似的“裂缝陷阱”（JSON chasm trap），比如下面的 JSON 文件：

另见〖关于JSON的“风扇陷阱”〗

{
  "results": [
    {
      "User": "Tim",
      "Skills": [
        {
          "Skill": "SQL",
          "SkillRating": 3
        },
        {
          "Skill": "JavaScript",
          "SkillRating": 4
        },
        {
          "Skill": "Python",
          "SkillRating": 5
        }
      ],
      "Languages": [
        {
          "Language": "English",
          "LangRating": 5
        }
      ]
    },
    {
      "User": "Bob",
      "Skills": [
        {
          "Skill": "SQL",
          "SkillRating": 5
        }
      ],
      "Languages": [
        {
          "Language": "English",
          "LangRating": 4
        },
        {
          "Language": "French",
          "LangRating": 3
        },
        {
          "Language": "Spanish",
          "LangRating": 5
        },
        {
          "Language": "Chinese",
          "LangRating": 3
        }
      ]
    },
    {
      "User": "Amy",
      "Skills": [
        {
          "Skill": "SQL",
          "SkillRating": 4
        },
        {
          "Skill": "Python",
          "SkillRating": 4
        },
        {
          "Skill": "PHP",
          "SkillRating": 5
        }
      ],
      "Languages": [
        {
          "Language": "English",
          "LangRating": 5
        },
        {
          "Language": "German",
          "LangRating": 2
        }
      ]
    }
  ]
}

当使用 Tableau 读取该文件时，会自动展开其中的嵌套数组以形成表格，读取结果如下：

在读取嵌套的 JSON 数据结构为二维表数据时，为了避免发散就需要避免对其进行扁平化展开，解决办法就是拆分识别成多张小表，比如该例中可识别成三张小表：