$lookup 在对象数组中查找 id [英] $lookup for id inside array of objects

问题描述

我有一些看起来像这样的模型:

const ExerciseDetailSchema = new mongoose.Schema({翻译:{名称: {en: { type: String, required: true },否:{ 类型:字符串}}}});const trainingDetailSchema = new mongoose.Schema({套: {练习:[锻炼练习]，单位:{ 类型:字符串}}});const WorkoutSets = new mongoose.Schema({代表:{ type: Number },重量:{ 类型:数量}});const WorkoutExercises = new mongoose.Schema({练习 ID:{ 类型:字符串，必填:真}，组数:[锻炼组]});

基本上，锻炼由集合组成，其中包含一些元数据，包括练习.这些练习是一个由练习集组成的数组.

我正在尝试进行查询，该查询将返回包括锻炼名称在内的锻炼详细信息，使其看起来像这样:

<代码>{_id:5f60dc1069c27c015ede4e3e"，套: {单位:'公制'，练习: [{_id:5f60dc1069c27c015ede4e3e"，练习 ID:5f60c3b7f93d8e00a1cdf414"，练习名称:{zh: "深蹲",否:Knebøy"},套: [{_id:5f60dc1069c27c015ede4e3f"，代表:10}，{_id:5f60dc1069c27c015ede4e40"，代表:20}]}]}}

这将是一个示例练习，例如:

<代码>{_id:5f60c3b7f93d8e00a1cdf414"，翻译:{名称: {zh: "深蹲",否:Knebøy"}}}

我尝试过使用 $lookup，如下所示:

const training = await WorkoutDetail.aggregate([{$查找:{来自:ExportDetail.collection.name，localField: "Sets.Exercises.ExerciseId",外国字段:_id"，如:练习细节"}}]);

但它总是只返回:ExerciseDetail: [] 对于应该加入"的部分.任何人都可以提供有关如何正确查询的任何帮助吗?

更新

我在这里的另一个问题中提出了关于对这些数据进行分组的问题，并收到了一个完美的答案.希望它也可以对其他人有所帮助:​​MongoDB $group(mongo 游乐场)

解决方案

由于 Exercises 是一个数组，你需要 $unwind 来扁平化数组.><预><代码>[{$unwind: "$Sets.Exercises";},{$查找:{来自:exerciseDetailSchema"，localField: "Sets.Exercises.ExerciseId",外国字段:_id"，如:练习细节"}}]

注意:要重组你需要使用$group.由于 lookup

有问题，所以我没有显示

工作 Mongo 游乐场

I have some models that look like this:

const exerciseDetailSchema = new mongoose.Schema(
    {
        Translations: {
            Name: {
                en: { type: String, required: true },
                no: { type: String }
            }
        }
    }
);

const workoutDetailSchema = new mongoose.Schema(
    {
        Sets: {
            Exercises: [ WorkoutExercises ],
            Units: { type: String }
        }
    }
);

const WorkoutSets = new mongoose.Schema({
    Reps: { type: Number },
    Weight: { type: Number }
});

const WorkoutExercises = new mongoose.Schema({
    ExerciseId: { type: String, required: true },
    Sets: [ WorkoutSets ]
});

Basically, workouts are made of Sets, which contain some metadata including exercises. These exercises is an array which is made of workout sets.

I am trying to make a query that will return to me the Workout Details including the Exercise Name, so that it can look like this:

{
   _id: "5f60dc1069c27c015ede4e3e",
   Sets: {
      Units: 'metric',
      Exercises: [
         {
            _id: "5f60dc1069c27c015ede4e3e",
            ExerciseId: "5f60c3b7f93d8e00a1cdf414",
            ExerciseName: {
               en: "Squat",
               no: "Knebøy"
            },
            Sets: [
               { _id: "5f60dc1069c27c015ede4e3f", Reps: 10 },
               { _id: "5f60dc1069c27c015ede4e40", Reps: 20 }
            ]
         }
      ]
   }
}

This would be with an example exercise like:

{
   _id: "5f60c3b7f93d8e00a1cdf414",
   Translations: {
      Name: {
         en: "Squat",
         no: "Knebøy"
      }
   }
}

I have tried using a $lookup, like this:

const workout = await WorkoutDetail.aggregate([
        {
            $lookup: {
                from: ExerciseDetail.collection.name,
                localField: "Sets.Exercises.ExerciseId",
                foreignField: "_id",
                as: "ExerciseDetail"
            }
        }
]);

But it is always returning with just: ExerciseDetail: [] for the part that is supposed to be "joined". Can anyone provide any help with how to query this properly?

UPDATE

I have asked in another question here about grouping this data, and received an answer that had done it perfectly. Hopefully it can be helpful to others also: MongoDB $group (mongo playground)

解决方案

Since the Exercises is an array, you need to $unwind to flat the array.

[
  {
    $unwind: "$Sets.Exercises"
  },
  {
    $lookup: {
      from: "exerciseDetailSchema",
      localField: "Sets.Exercises.ExerciseId",
      foreignField: "_id",
      as: "ExerciseDetail"
    }
  }
]

Note : To restructure you need to use $group. I've not shown since you had a problem with lookup

Working Mongo playground

这篇关于$lookup 在对象数组中查找 id的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！