在MongoDB的聚合管道中，如何重复所有字段键并设置新值在$project阶段？

huangapple
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英文:

How to repeat all fields key and set the new value in $project stage in aggregate mongodb?

问题

我有一个模式模型，其中有许多字段，就像下面的示例一样，我想将suggest_foo中的根字段克隆到聚合的$project阶段，而不必手动重写这些字段，然后根据我的逻辑设置这些字段的新值。

示例：

  • 模式模型：
  1. const fooSchema = new Schema({
  2.    suggest_foo: {
  3.        foo1: String,
  4.        foo2: String,
  5.        foo3: String,
  6.        foo4: String,
  7.        foo5: String,
  8.    }
  9.    // ...
  10. })
  • 种子数据：
  1. {
  2.    suggest_foo: {
  3.        foo1: 'Foo1',
  4.        foo2: 'Foo2',
  5.        foo3: 'Foo3',
  6.        foo4: 'Foo4',
  7.        foo5: 'Foo5',
  8.    }
  9. }
  • 聚合查询代码：
  1. fooSchema.aggregate([
  2.    // ...
  3.    {
  4.        $project: {
  5.            // 我想要克隆suggest_foo中的根字段（例如：foo1、foo2、foo(n)）到这里。
  6.        }
  7.    }
  8. ])

我期望的输出结果如下：

  1. {
  2.    foo1: 'Foo1 maybe you like',
  3.    foo2: 'Foo2 maybe you like',
  4.    foo3: 'Foo3 maybe you like',
  5.    foo4: 'Foo4 maybe you like',
  6.    foo5: 'Foo5 maybe you like',
  7. }
英文:

I have a schema model with so many fields like below example, I want to clone root field in suggest_foo to $project stage of aggregation without having to manually rewrite those fields and then set those fields with new value as my logic.

Example:

  • schema model:

    1. const fooSchema = new Schema({
    2.    suggest_foo: 
    3.      foo1: String,
    4.      foo2: String,
    5.      foo3: String,
    6.      foo4: String,
    7.      foo5: String,
    8.    }
    9.    ...
    10. })

  • seeds data:

    1. {
    2.    suggest_foo: {
    3.      foo1: 'Foo1',
    4.      foo2: 'Foo2',
    5.      foo3: 'Foo3',
    6.      foo4: 'Foo4',
    7.      foo5: 'Foo5',
    8.    }
    9. }

  • aggregate query code:

    1. fooSchema.aggregate([
    2.    ...
    3.    {
    4.      $project: {
    5.         // I want to clone root in suggest_foo (eg: foo1, foo2, foo(n)...) to be here.
    6.      }
    7.    }
    8. ])

My output result that I expected look like:

  1.   {
  2.      foo1: 'Foo1 maybe you like',
  3.      foo2: 'Foo2 maybe you like',
  4.      foo3: 'Foo3 maybe you like',
  5.      foo4: 'Foo4 maybe you like',
  6.      foo5: 'Foo5 maybe you like',
  7.   }

答案1

得分: 1

一种选择是使用$replaceRoot与$arrayToObject和$objectToArray，因为这将允许您在循环中操作数组：

  1. db.collection.aggregate([
  2.   {$replaceRoot: {
  3.       newRoot: {
  4.         $arrayToObject: {
  5.           $map: {
  6.             input: {$objectToArray: "$suggest_foo"},
  7.             in: {
  8.               v: {$concat: ["$$this.v", "也许你会喜欢"]},
  9.               k: "$$this.k"
  10.             }
  11.           }
  12.         }
  13.       }
  14.   }}
  15. ])

在播放示例上查看它是如何工作的。

英文:

One option is to use $replaceRoot with $arrayToObject and $objectToArray as this will allow you to manipulate array in a loop:

  1. db.collection.aggregate([
  2.   {$replaceRoot: {
  3.       newRoot: {
  4.         $arrayToObject: {
  5.           $map: {
  6.             input: {$objectToArray: "$suggest_foo"},
  7.             in: {
  8.               v: {$concat: ["$$this.v", " maybe you like"]},
  9.               k: "$$this.k"
  10.             }
  11.           }
  12.         }
  13.       }
  14.   }}
  15. ])

See how it works on the playground example

huangapple
  • 本文由 发表于 2023年1月8日 01:27:45
  • 转载请务必保留本文链接：https://go.coder-hub.com/75042377.html
  • mongodb
  • mongoose
  • node.js
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