如何使用官方的Mongo驱动程序在MongoDB中查找嵌套文档。

huangapple
go评论115阅读模式
英文:

How to find nested documents mongodb using the official mongo driver

问题

我有这个文档，并希望对其进行过滤，以获取 Content 数组内的文档：

  1. [
  2.     {
  3.         "ID": "61f1244daeaea5f165851fc9",
  4.         "name": "Mulandi",
  5.         "author": "Owayo",
  6.         "description": "dnjsfnvlksfnvls",
  7.         "created_at": "2022-01-26T10:37:01.558Z",
  8.         "Section": [
  9.             {
  10.                 "ID": "61f557213fd9b086c3a422c5",
  11.                 "Title": "Weee",
  12.                 "Content": [
  13.                     {
  14.                         "ID": "61f5586e3fd9b086c3a422dc",
  15.                         "Subsection_Title": "Idk",
  16.                         "Content": "Something"
  17.                     }
  18.                 ]
  19.             }
  20.         ]
  21.     }
  22. ]

我应该如何过滤这个文档？我尝试了以下方法，但没有成功：

  1. pipeline := []bson.M{
  2.     {"$match": bson.M{"Name": name}},
  3.     {"$unwind": "$Section"},
  4.     {"$unwind": "$Section.Content"},
  5.     {"$project": bson.M{
  6.         "Section.Title":                sectiontitle,
  7.         "Section.Content.subsectionid": iuud,
  8.     }},
  9. }
  10. iter, err := collection.Aggregate(ctx, pipeline)
  11. if err != nil {
  12.     return nil, err
  13. }
  14. var elem models.Course
  15. for iter.Next(ctx) {
  16.     var elem models.Section
  17.     err = iter.Decode(&elem)
  18.     if err != nil {
  19.         log.Fatal(err)
  20.     }
  21. }

请注意，我只是将代码部分翻译成了中文，其他部分保持原样。

英文:

I have this document and would like to filter it to get and document inside the Content array :

  1. [
  2. {
  3.     "ID": "61f1244daeaea5f165851fc9",
  4.     "name": "Mulandi",
  5.     "author": "Owayo",
  6.     "description": "dnjsfnvlksfnvls",
  7.     "created_at": "2022-01-26T10:37:01.558Z",
  9.     "Section": [
  10.         {
  11.             "ID": "61f557213fd9b086c3a422c5",
  12.             "Title": "Weee",
  13.             "Content": [
  14.                 {
  15.                     "ID": "61f5586e3fd9b086c3a422dc",
  16.                     "Subsection_Title": "Idk",
  17.                     "Content": "Something"
  18.                 }
  19.             ]
  20.         }
  21.     ],
  22. }

]

how should i go about so as to filter this document i tried this but it didn't work :

  1. pipeline := []bson.M{
  2. 		{"$match": bson.M{"Name": name}},
  3. 		{"$unwind": "$Section"},
  4. 		{"$unwind": "$Section.Content"},
  5. 		{"$project": bson.M{
  6. 			"Section.Title":                sectiontitle,
  7. 			"Section.Content.subsectionid": iuud,
  8. 		}},
  9. 	}
  10. 	iter, err := collection.Aggregate(ctx, pipeline)
  11. 	if err != nil {
  12. 		return nil, err
  13. 	}
  14. 	var elem models.Course
  15. 	for iter.Next(ctx) {
  16. 		var elem models.Section
  17. 		err = iter.Decode(&elem)
  18. 		if err != nil {
  19. 			log.Fatal(err)
  20. 		}
  21. 	}

答案1

得分: 2

  1. db.collection.aggregate([
  2.   {
  3.     "$match": {
  4.       "name": "Mulandi"
  5.     }
  6.   },
  7.   {
  8.     "$unwind": "$Section"
  9.   },
  10.   {
  11.     "$unwind": "$Section.Content"
  12.   },
  13.   {
  14.     "$match": {
  15.       "Section.Content.ID": "61f5586e3fd9b086c3a422dc"
  16.     }
  17.   },
  18.   {
  19.     "$project": {
  20.       "Subsection_Title": "$Section.Content.Subsection_Title",
  21.       "Content": "$Section.Content.Content",
  22.       "_id": "$Section.Content.ID"
  23.     }
  24.   }
  25. ])

mongoplayground

  2. <details>
  3. <summary>英文:</summary>

db.collection.aggregate([
{
"$match": {
"name": "Mulandi"
}
},
{
"$unwind": "$Section"
},
{
"$unwind": "$Section.Content"
},
{
"$match": {
"Section.Content.ID": "61f5586e3fd9b086c3a422dc"
}
},
{
"$project": {
"Subsection_Title": "$Section.Content.Subsection_Title",
"Content": "$Section.Content.Content",
"_id": "$Section.Content.ID"
}
}
])

  2. [mongoplayground][1]
  5.   [1]: https://mongoplayground.net/p/gQyDOIuqtnF
  7. </details>
  11. # 答案2
  12. **得分**: 0
  14. iuud, _ := primitive.ObjectIDFromHex(subsectionid)
  15. pipeline := []bson.M{
  16.     {"$match": bson.M{"Name": name}},
  17.     {"$unwind": "$Section"},
  18.     {"$unwind": "$Section.Content"},
  19.     {"$match": bson.M{"Section.Content.ID": iuud}},
  20.     {"$project": bson.M{
  21.         "Subsection_Title": "$Section.Content.Subsection_Title",
  22.         "Content":         "$Section.Content.Content",
  23.         "_id": "$Section.Content.ID",
  24.     }},
  25. }
  26. iter, err := collection.Aggregate(ctx, pipeline)
  27. if err != nil {
  28.     return nil, err
  29. }
  30. var results []bson.M
  31. if err = iter.All(context.TODO(), &results); err != nil {
  32.     log.Fatal(err)
  33. }
  35. 这段代码帮助我找到了嵌套的文档，感谢 @YuTing 的帮助。
  37. <details>
  38. <summary>英文:</summary>
  40.     iuud, _ := primitive.ObjectIDFromHex(subsectionid)
  41.     pipeline := []bson.M{
  42. 		{&quot;$match&quot;: bson.M{&quot;Name&quot;: name}},
  43. 		{&quot;$unwind&quot;: &quot;$Section&quot;},
  44. 		{&quot;$unwind&quot;: &quot;$Section.Content&quot;},
  45. 		{&quot;$match&quot;: bson.M{&quot;Section.Content.ID&quot;: iuud}},
  46. 		{&quot;$project&quot;: bson.M{
  47. 			&quot;Subsection_Title&quot;: &quot;$Section.Content.Subsection_Title&quot;,
  48. 			&quot;Content&quot;:       &quot;$Section.Content.Content&quot;,
  49.             &quot;_id&quot;: &quot;$Section.Content.ID&quot;,
  50. 		}},
  51. 	} 
  52. 	iter, err := collection.Aggregate(ctx, pipeline)
  53. 	if err != nil {
  54. 		return nil, err
  55. 	}
  56. 	var results []bson.M
  57. 	if err = iter.All(context.TODO(), &amp;results); err != nil {
  58. 		log.Fatal(err)
  59. 	}
  61. This helped me finding the nested documents Thanks @YuTing 
  63. </details>

huangapple
  • 本文由 发表于 2022年1月30日 14:32:12
  • 转载请务必保留本文链接：https://go.coder-hub.com/70912402.html
  • go
  • mongodb
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定