设置 TTL 在 Mongodb c# 中不起作用 [英] Set TTL doesnt work in Mongodb c#

问题描述

我在 c# 中使用 MongoDb.我插入一个像下面这样的学生

I am using MongoDb in c# . I insert a Student Like below

 _client = new MongoClient(new MongoClientSettings
        {
            Server = new MongoServerAddress("172.1.9.8", 27017)
        });
        _database = _client.GetDatabase("MongoSample");

        Student st=new Student()
        {
            Name = "Ali",
            Family = "Valid",
            Age = 25,
            expireAt = DateTime.Now.AddSeconds(30)
        };
  var collection = _database.GetCollection<Student>("Students");
     collection.InsertOne(st);

我想设置一个 TTL 以在几秒钟后删除数据，我尝试这样做:

I want to set a TTL to Remove data after some seconds , I try to do that like this :

 var collection = _database.GetCollection<Student>("Students");
        var indexs = collection.Indexes.CreateOne(Builders<Student>.IndexKeys.Ascending("Name"),
            new CreateIndexOptions { ExpireAfter = new TimeSpan(0, 0, 10) });

        collection.InsertOne(st);

但它不起作用.我的模型是:

but it does not work . my model is :

 public class Student
{
    public string Name { get; set; }
    public string Family { get; set; }
    public int Age { get; set; }
    [BsonElement("expireAt")]
    public DateTime expireAt { get; set; }
}

注意:我对 DateTime 有问题，db 中存储的数据与 Visual Studio 中的 Set Date 不同

Note : and I have problem with DateTime , stored data in db is different with Set Date in Visual Studio

推荐答案

再次阅读 Mongodb 文档后，我的代码有错误添加了 Index .TTL 有一些限制.

After reading Mongodb documents again , there was a mistake in my code to add Index . there some restriction to work TTL .

如果文档中的索引字段不是日期或保存日期值的数组，则文档不会过期.

我尝试在 Name 上设置索引，但它不包含 Date.

I'v tried to set Index on Name and it does not contain Date.

下面的代码工作正常.

var indexKeysDefinition = Builders<Student>.IndexKeys.Ascending("expireAt");
var indexOptions = new CreateIndexOptions { ExpireAfter = new TimeSpan(0, 0, 60) };
var indexModel = new CreateIndexModel<Student>(indexKeysDefinition, indexOptions);
collection.Indexes.CreateOne(indexModel);

感谢 @NeilLunn.

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