如何使用 .net core 中的 C# mongo Db 驱动程序将多个文档组合/合并到一个 C# 对象

Question

我在 mongdo DB 上有三个文档，如下例所示（祖文档、父文档和子文档）。我希望使用 C# mondoDB 驱动程序将对象包含在结果中。场景是如果孙子没有属性/值（例如 gprop2,fprop2 ），那么它将从父/子父级获取属性/值，但同时如果所有文档都具有相同的属性（例如“cprop1”） ，那么毕业生孩子将覆盖来自父母和毕业生父母的值。毕业生孩子也可以拥有自己的属性（“sprop2”），该属性应包含在最终结果中。我通过手动检查/复制属性/值给子项获得了最终结果，但我正在寻找有效的解决方案。有没有办法在.NET core中使用C# mongoDb驱动来实现它？

祖父母医生

  {
    "cprop1": "gval1",
    "gprop2": "gval2"
    "gppcrop2": "gpcval22",
    "assets" : [
        {
          "gasset1": "gassetVal1",
          "gcasset1": "gcassetVal1"
        },......
     ]
  }

家长文档

  {
    "cprop1": "fval1",
    "fprop2": "fval2",
    "gppcrop2": "gpcval33",
    "assets" : [
        {
          "passet1": "passetVal1",
          "gcasset1": "gcassetVal2"
        },.......
     ]
  }

儿童医生

  {
    "cprop1": "sval1",
    "sprop2": "sval2",
    "assets" : [
        {
          "sasset1": "sassetVal1",
          "gcasset1": "gcassetVal3"
        },..........
     ]
  }

最终结果

{

    "cprop1": "sval1",
    "gprop2": "gval2",
    "fprop2": "fval2",
    "gppcrop2": "gpcval33",
    "sprop2": "sval2",
    "assets": [
    {
     "gasset1": "gassetVal1",
     "passet1": "passetVal1"
     "sasset1": "sassetVal1",
     "gcasset1": "gcassetVal3"
    },....
  ]

  }

Answer 1

您可以使用合并方法来完成此操作。

static void Main(string[] args)
{
    BsonDocument gp = new BsonDocument("cprop1", "gval1").Add("gprop2", "gval2").Add("gppcrop2", "gpcval22");
    BsonDocument parent = new BsonDocument("cprop1", "fval1").Add("fprop2", "fval2").Add("gppcrop2", "gpcval33");
    BsonDocument child = new BsonDocument("cprop1", "sval1").Add("sprop2", "sval2");

    child.Merge(parent);
    child.Merge(gp);

    Console.WriteLine(child.ToJson(new MongoDB.Bson.IO.JsonWriterSettings() { Indent = true }));

}

你得到了

{
  "cprop1" : "sval1",
  "sprop2" : "sval2",
  "fprop2" : "fval2",
  "gppcrop2" : "gpcval33",
  "gprop2" : "gval2"
}

Answer 2

public async Task<ReplaceOneResult> MergeOneAsync<T>(IClientSessionHandle? session, FilterDefinition<BsonDocument> filter, T replacement, FindOptions<BsonDocument, BsonDocument> findOptions = null, ReplaceOptions replaceOptions = null,  CancellationToken cancellationToken = default) where T : AbstractModel
{
    var collection = GetDatabase().GetCollection<BsonDocument>(Collection);
    IAsyncCursor<BsonDocument> cursor = null;
    ReplaceOneResult result = null;
    if (session != null)
        cursor = await collection.FindAsync(session, filter, findOptions, cancellationToken);
    else
        cursor = await collection.FindAsync(filter, findOptions, cancellationToken);
   
    var list = await cursor.ToListAsync();

    if (list != null && list.Any())
    {
        var foundDoc = list.FirstOrDefault();
        var docAsStr = BsonDocument.Parse(JsonConvert.SerializeObject(replacement));
        foreach (var element in docAsStr) {
            if (element.Name != "_id")
            {
                foundDoc[element.Name] = element.Value;
            }
        }
        if (session != null)
            result = await collection.ReplaceOneAsync(session, filter, foundDoc, replaceOptions, cancellationToken);
        else
            result = await collection.ReplaceOneAsync(filter, foundDoc, replaceOptions, cancellationToken);
    }
    return result;
}