删除mongodb

Question

当我在MongoDB中创建一个新的BsonDocument

时，我有了结构

var doct = new BsonDocument
            {
                { "fbId", "" },
                { "Name", NameTxt.Text.ToString() },
                { "pass", PasswTxt.Text.ToString() },
                { "Watchtbl", new BsonArray
                                {
                                    new BsonDocument
                                    {
                                        { "wid", "" },
                                        { "name", "" },
                                        { "Symboles", new BsonArray
                                                        {
                                                            new BsonDocument
                                                            {
                                                                { "Name", "" }
                                                            }
                                                        }
                                        }
                                    }
                                } 
                }

            };

我想知道如何删除一些空记录，这是我尝试在MongoDB中获取数据时的样子

    { "_id" : ObjectId("582c77454d08e326104879cb"), 
"fbId" : "", 
"Name" : "user", 
"pass" : "user", 
"Watchtbl" : 
[ 
    { "wid" : "", "name" : "", "Symboles" : [ { "Name" : "" } ] }, 
    { "wid" : "0000", "name" : "bought stock2", "Symboles" : [ ] }, 
    { "wid" : "", "name" : "", "Symboles" : [ { "Name" : "" } ] }, 
    { "wid" : "", "name" : "", "Symboles" : [ { "Name" : "" } ] }, 
    { "wid" : "", "name" : "", "Symboles" : [ { "Name" : "" } ] }, 
    { "wid" : "", "name" : "", "Symboles" : [ { "Name" : "" } ] } 
] }

Answer 1

序列化数据后，您可以对POCO类进行任何复杂的更新。请查看以下内容：

// add user into datagridview from MongoDB Colelction Watchtbl
var client = new MongoClient("mongodb://dataservername:27017");

var database = client.GetDatabase("WatchTblDB");
var collectionWatchtbl = database.GetCollection<BsonDocument>("UserWatchtbl");
var filter = new BsonDocument();
var users = new List<UserWatchTblCls>();
var cursor = collectionWatchtbl.FindAsync(filter).Result;
cursor.ForEachAsync(batch =>
{
    users.Add(BsonSerializer.Deserialize<UserWatchTblCls>(batch));
});

foreach (var user in users)
{
    List<WatchTblCls> removables = new List<WatchTblCls>();
    foreach (var watchTbl in user.WatchTbls)
        if (string.IsNullOrEmpty(watchTbl.WID) && string.IsNullOrEmpty(watchTbl.Name) && watchTbl.Symbols.Count == 1 && string.IsNullOrEmpty(watchTbl.Symbols.Single().Name))
            removables.Add(watchTbl);

    foreach (WatchTblCls removable in removables)
        user.WatchTbls.Remove(removable);

    collectionWatchtbl.UpdateOne(Builders<BsonDocument>.Filter.Eq("_id", user.Id), Builders<BsonDocument>.Update.Set("Watchtbl", user.WatchTbls));
}

这些类看起来像这样：

public class UserWatchTblCls
{
    [BsonId]
    [BsonElement("_id")]
    public ObjectId Id { get; set; }

    public string fbId { get; set; }
    public string Name { get; set; }

    [BsonElement("pass")]
    public string Pass { get; set; }

    [BsonElement("Watchtbl")]
    public List<WatchTblCls> WatchTbls { get; set; }
}

public class WatchTblCls
{
    [BsonElement("wid")]
    public string WID { get; set; }

    [BsonElement("name")]
    public string Name { get; set; }

    [BsonElement("Symboles")]
    public List<SymboleCls> Symbols { get; set; }
}

public class SymboleCls
{
    public string Name { get; set; }
}

Answer 2

另一种可能的解决方案是一次性使用pull：

collectionWatchtbl.UpdateMany(
    Builders<BsonDocument>.Filter.Empty,
        Builders<BsonDocument>.Update.PullFilter("Watchtbl",
            Builders<BsonDocument>.Filter.Eq("name", "") &
            Builders<BsonDocument>.Filter.Eq("wid", "") &
            Builders<BsonDocument>.Filter.Size("Symboles", 1) &
            Builders<BsonDocument>.Filter.ElemMatch("Symboles",
                Builders<BsonDocument>.Filter.Eq("Name", ""))));