C# mongodb 从双重嵌套数组中删除文档

Question

首先，我找到了python和mongo shell的很多解决方案，但是C#没有，这就是我创建这个线程的原因。

数据库有一个项目列表，项目有一个文件列表，文件列表有一个翻译列表。 任务是从翻译数组中删除具有给定 ID 的翻译文档。 我们知道所有信息来查找文档，例如项目的_id、文件的_id和翻译的ID。

这是它的外观：

[{
  "_id": "62e237a1d866d82c881629a1",
  "Name": "test92",
  "PrimarySourceLanguage": "eng",
  "PivotSourceLanguage": "hun",
  "TargetLanguages": [
    "prs",
    "fre-BE",
    "fre-CH"
  ],
  "Files": [
    {
      "segments": [
        
      ],
      "Name": "smallBatch_test.json",
      "_id": "f7b02afb-ec62-439b-be6d-403b8f1434ff",
      "ImportDate": {
        "$date": {
          "$numberLong": "1658992556090"
        }
      },
      "TargetLanguages": null,
      "Translation": [
        {
          "ID": "e5e09f84-64d7-40a4-87f7-a90f5a956c32",
          "SourceLanguage": "eng",
          "TargetLanguage": "prs",
          "TranslatedString": null,
          "ProjectGuid": "62e237a1d866d82c881629a1",
          "FileGuid": "f7b02afb-ec62-439b-be6d-403b8f1434ff",
          "Status": "Translation deleted"
        },
        {
          "ID": "8d4ca52c-0063-474a-94db-fd2d8b1f2cee",
          "SourceLanguage": "eng",
          "TargetLanguage": "prs",
          "TranslatedString": "Boci múú",
          "ProjectGuid": "62e237a1d866d82c881629a1",
          "FileGuid": "f7b02afb-ec62-439b-be6d-403b8f1434ff",
          "Status": null
        },
        {
          "ID": "2929dc9e-5254-4093-93bc-fbcdcb265ea7",
          "SourceLanguage": "eng",
          "TargetLanguage": "prs",
          "TranslatedString": "Bocikaaa",
          "ProjectGuid": "62e237a1d866d82c881629a1",
          "FileGuid": "f7b02afb-ec62-439b-be6d-403b8f1434ff",
          "Status": "Translated"
        }
      ]
    }
  ],
  "TemplateGuid": {
    "$binary": {
      "base64": "AAAAAAAAAAAAAAAAAAAAAA==",
      "subType": "03"
    }
  },
  "Deadline": {
    "$date": {
      "$numberLong": "1659165300000"
    }
  },
  "TMs": [
    null
  ],
  "TBs": [
    null
  ],
  "Domain": null,
  "Client": null
}]

我尝试使用 pullfilter 或使用带有 Pull 命令的更新，但它们都不起作用:(

Answer 1

以下实现假设翻译 id 是全局唯一的，因此没有两个文件具有相同 id 的翻译。 它使用带有映射文件的聚合管道的更新，以便只有翻译包含在 ID 中，而不是要删除的 ID：

db.collection.update({
  _id: "62e237a1d866d82c881629a1"
},
[
  {
    "$set": {
      "Files": {
        "$map": {
          "input": "$Files",
          "as": "file",
          "in": {
            "$mergeObjects": [
              "$$file",
              {
                Translation: {
                  "$filter": {
                    "input": "$$file.Translation",
                    "as": "translation",
                    "cond": {
                      "$ne": [
                        "$$translation.ID",
                        "e5e09f84-64d7-40a4-87f7-a90f5a956c32"
                      ]
                    }
                  }
                }
              }
            ]
          }
        }
      }
    }
  }
])

此Playground包含示例数据的简化版本并包含普通更新。

缺点是 C# 中对聚合管道更新的支持并未涵盖 MongoDB 提供的所有选项。 但是您可以使用BsonDocument来定义管道（我假设 model class 称为Project ）：

var filter = Builders<Project>.Filter
  .Eq(x => x.Id, "62e237a1d866d82c881629a1");
var pipeline = new EmptyPipelineDefinition<Project>()
  .AppendStage(new BsonDocument("$set", 
    new BsonDocument("Files", 
    new BsonDocument("$map", 
    new BsonDocument
                {
                    { "input", "$Files" }, 
                    { "as", "file" }, 
                    { "in", 
                        new BsonDocument("$mergeObjects", 
                        new BsonArray
                        {
                            "$$file",
                            new BsonDocument("Translation", 
                            new BsonDocument("$filter", 
                            new BsonDocument
                                    {
                                        { "input", "$$file.Translation" }, 
                                        { "as", "translation" }, 
                                        { "cond", 
                                          new BsonDocument("$ne", 
                                          new BsonArray
                                            {
                                                "$$translation.ID",
                                                "e5e09f84-64d7-40a4-87f7-a90f5a956c32"
                                            }) }
                                    }))
                        }) }
                }))),
                BsonDocumentSerializer.Instance)
  .As<Project, BsonDocument, Project>();
var update = Builders<Project>.Update.Pipeline(pipeline);
var result = await coll.UpdateOneAsync(filter, update);