mongoose 分页MongoDB聚合响应

n6lpvg4x 于 11个月前发布在 Go

关注(0)|答案(2)|浏览(111)

我有一个拥有技能的用户数据库。我已经建立了一种方法，使用mongoose中包含的am聚合方法在数据库中查找用户。根据我输入聚合的搜索条件，结果可能太大，无法在我的前端应用程序上实际显示。我很好奇如何使用典型的限制，页面，并像在典型的GET请求中那样跳过变量。
下面是我的聚合查询：

const foundUsers = await User.aggregate([
{
  $addFields: {
    matchingSkills: {
      $filter: {
        input: '$skills',
        cond: {
          $or: test,
        },
      },
    },
    requiredSkills,
  },
},
{
  $addFields: {
    // matchingSkills: '$$REMOVE',
    percentageMatch: {
      $multiply: [
        { $divide: [{ $size: '$matchingSkills' }, skillSearch.length] }, // yu already know how many values you need to pass, thats' why `2`
        100,
      ],
    },
  },
},
{
  $addFields: {
    matchingSkillsNames: {
      $map: {
        input: '$matchingSkills',
        as: 'matchingSkill',
        in: '$$matchingSkill.skill',
      },
    },
  },
},
{
  $addFields: {
    missingSkills: {
      $filter: {
        input: '$requiredSkills',
        cond: {
          $not: {
            $in: ['$$this', '$matchingSkillsNames'],
          },
        },
      },
    },
  },
},
{
  $match: { percentageMatch: { $gte: 25 } },
},
]);

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将这些技能传递给这个聚合函数：

{
"skillSearch": [
    {
      "class": "skills",
      "skill": "SQL",
       "operator": "GT",
  "yearsExperience": 6
    },
 {
  "class": "skills",
  "skill": "C",
  "operator": "GT",
  "yearsExperience": 1
}
  ]
}

型
将导致类似于以下的响应：

{
  "_id": "60184ce81e65633873d709aa",
  "name": "Brad",
  "email": "[email protected]",
  "password": "$2a$12$37v2RwaO5LhSMT8GJQSZyel.Aawn6AmlqqSOkZtopqIIXyJ0LRBfu",
  "__v": 0,
  "skills": [
      {
          "_id": "60a306ce819cde701c1934a8",
          "skill": "SQL",
          "yearsExperience": 8
      },
      {
          "_id": "60a306ce819cde701c1934a9",
          "skill": "C",
          "yearsExperience": 5
      },
      {
          "_id": "60a306ce819cde701c1934aa",
          "skill": "PL/I",
          "yearsExperience": 2
      },
      {
          "_id": "60a306ce819cde701c1934ab",
          "skill": "Awk",
          "yearsExperience": 9
      }
  ],
  "matchingSkills": [
      {
          "_id": "60a306ce819cde701c1934a8",
          "skill": "SQL",
          "yearsExperience": 8
      },
      {
          "_id": "60a306ce819cde701c1934a9",
          "skill": "C",
          "yearsExperience": 5
      }
  ],
  "requiredSkills": [
      "SQL",
      "C"
  ],
  "percentageMatch": 100,
  "matchingSkillsNames": [
      "SQL",
      "C"
  ],
  "missingSkills": []
},

型

mongoose

来源：https://stackoverflow.com/questions/67596384/paginate-mongodb-aggregation-response

2条答案

按热度按时间

r8uurelv1#

对于分页，需要从前端传递page和size

$sort对文档进行排序，
$skip跳过文档。例如：如果你在第二页，你需要10行，你需要跳过前10个文档
$limit到跳过后需要显示多少文档

这里是代码

db.collection.aggregate([
  {
    $sort: {
      _id: 1
    }
  },
  {
    $skip: 0  // page*size
  },
  {
    $limit: 10  // size
  }
])

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工作Mongo playground

更重要的是，分页也需要全部元素，

db.collection.aggregate([
  {
    "$facet": {
      "elements": [
        {
          "$group": {
            "_id": null,
            "count": { "$sum": 1 }
          }
        }
      ],
      "data": [
        { $sort: { _id: 1 } },
        { $skip: 0 }, // page*size 
        { $limit: 10 } // size
      ]
    }
  },
  { "$unwind": "$elements" },
  {
    "$addFields": {
      "elements": "$$REMOVE",
      "totalRecords": "$elements.count"
    }
  }
])

型

工作Mongo playground

赞(0）回复(0）举报 11个月前

uemypmqf2#

对于新读者，正如已经回答的那样，您可以轻松地将跳过和限制阶段添加到聚合中。我想添加的是使用easy-mongoose-paginate包来为您解决这个问题https://www.npmjs.com/package/easy-mongoose-paginate#easy-mongoose-paginate

return Model.aggregate([
    {
      $match: { percentageMatch: { $gte: 25 } },
    },
    {
      $skip: (page - 1) * 10
    },
    {
      $limit: 10
    }
  ])

字符串

赞(0）回复(0）举报 11个月前

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mongoose 分页MongoDB聚合响应

2条答案

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