如何在 Mongoose 中检查重复文件？

Question

这是我收藏中的嵌套文档示例：

"person" : [
  {
    "title" : "front-end developer",
    "skills" : [
      {
        "name" : "js",
        "project" : "1",
      },
      {
        "name" : "CSS",
        "project" : "5",
      }
    ]
  },
  {
    "title" : "software engineer",
    "skills" : [
      {
        "name" : "Java",
        "project" : "1",
      },
      {
        "name" : "c++",
        "project" : "5",
      }
    ]
  }
]

是否有一种简单的方法可以确定其他文档是否与该对象相同，例如具有相同的键、值和数组索引？目前我检查重复的方法很长，需要多个嵌套循环。任何帮助将不胜感激。谢谢！

Answer 1

如果您想在您的集合中获取相同（显然，_id 字段除外）文档的列表，您可以这样做：

collection.aggregate({
    $project: {
        "_id": 1, // keep the _id field where it is anyway
        "doc": "$$ROOT" // store the entire document in the "doc" field
    }
}, {
    $project: {
        "doc._id": 0 // remove the _id from the stored document because we do not want to compare it
    }
}, {
    $group: {
        "_id": "$doc", // group by the entire document's contents as in "compare the whole document"
        "ids": { $push: "$_id" }, // create an array of all IDs that form this group
        "count": { $sum: 1 } // count the number of documents in this group
    }
}, {
    $match: {
        "count": { $gt: 1 } // only show what's duplicated
    }
})

与聚合框架一样，您可以通过注释掉所有步骤然后逐步再次激活所有内容来尝试了解每个步骤中究竟发生了什么。