MongoDB：自动生成的 ID 为零

发布于 2024-10-10 03:48:25 字数 1172 浏览 0 评论 0原文

我正在使用 MongoDB 和官方 C# 驱动程序 0.9

我只是检查嵌入简单文档的工作原理。

有 2 个简单的类：

public class User
{
    public ObjectId _id { get; set; }
    public string Name { get; set; }
    public IEnumerable<Address> Addresses { get;set; }
}

public class Address
{
    public ObjectId _id { get; set; }
    public string Street { get; set; }
    public string House { get; set; }
}

我创建一个新用户：

var user = new User
{
    Name = "Sam",
    Addresses = (new Address[] { new Address { House = "BIGHOUSE", Street = "BIGSTREET" } })
};

collection.Insert(user.ToBsonDocument());

用户已成功保存，他的地址也是如此。

在 MongoDB shell 中输入后

db.users.find()

，我得到以下结果：

{ "_id" : ObjectId("4e572f2a3a6c471d3868b81d"), "Name" : "Sam",  "Addresses" : [
        {
                "_id" : ObjectId("000000000000000000000000"),
                "Street" : "BIGSTREET",
                "House" : "BIGHOUSE"
        }
] }

为什么地址'对象 id 为 0？

不过，使用地址进行查询是有效的：

collection.FindOne(Query.EQ("Addresses.Street", streetName));

它返回用户“Sam”。

原文

I'm using MongoDB and official C# driver 0.9

I'm just checking how embedding simple documents works.

There are 2 easy classes:

public class User
{
    public ObjectId _id { get; set; }
    public string Name { get; set; }
    public IEnumerable<Address> Addresses { get;set; }
}

public class Address
{
    public ObjectId _id { get; set; }
    public string Street { get; set; }
    public string House { get; set; }
}

I create a new user:

var user = new User
{
    Name = "Sam",
    Addresses = (new Address[] { new Address { House = "BIGHOUSE", Street = "BIGSTREET" } })
};

collection.Insert(user.ToBsonDocument());

The user is successfully saved, so is his address.

After typing

db.users.find()

in MongoDB shell, I got the following result:

{ "_id" : ObjectId("4e572f2a3a6c471d3868b81d"), "Name" : "Sam",  "Addresses" : [
        {
                "_id" : ObjectId("000000000000000000000000"),
                "Street" : "BIGSTREET",
                "House" : "BIGHOUSE"
        }
] }

Why is address' object id 0?

Doing queries with the address works though:

collection.FindOne(Query.EQ("Addresses.Street", streetName));

It returns the user "Sam".

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半葬歌 2024-10-17 03:48:25

与其说这是一个错误，不如说这是一个未满足期望的情况。只有顶层 _id 会自动分配一个值。任何嵌入的 _ids 都应由客户端代码分配值（使用 ObjectId.GenerateNewId）。也有可能您甚至不需要 Address 类中的 ObjectId（它的目的是什么？）。

回复收藏 0 原文

泡沫很甜 2024-10-17 03:48:25

使用 BsonId 属性：

public class Address
{
    [BsonId]
    public string _id { get; set; }
    public string Street { get; set; }
    public string House { get; set; }
}

识别 Id 字段或属性
识别哪个字段或属性
类是你可以写的Id：
公共类 MyClass {
    [BsonId]
    公共字符串 SomeProperty { 获取；放; }
}

驱动程序教程

编辑

它实际上不起作用。我稍后会检查原因。
如果您需要让它工作，请使用以下命令：

    [Test]
   public void Test()
    {
        var collection = Read.Database.GetCollection("test");

        var user = new User
        {
            Name = "Sam",
            Addresses = (new Address[] { new Address { House = "BIGHOUSE", Street = "BIGSTREET", _id = ObjectId.GenerateNewId().ToString() } })
        };

        collection.Insert(user.ToBsonDocument());
    }

Use BsonId attribute:

public class Address
{
    [BsonId]
    public string _id { get; set; }
    public string Street { get; set; }
    public string House { get; set; }
}

Identifying the Id field or property
To identify which field or property of
a class is the Id you can write:
public class MyClass {
    [BsonId]
    public string SomeProperty { get; set; }
}

Driver Tutorial

Edit

It's actually not working. I will check later why.
If you need get it work use following:

    [Test]
   public void Test()
    {
        var collection = Read.Database.GetCollection("test");

        var user = new User
        {
            Name = "Sam",
            Addresses = (new Address[] { new Address { House = "BIGHOUSE", Street = "BIGSTREET", _id = ObjectId.GenerateNewId().ToString() } })
        };

        collection.Insert(user.ToBsonDocument());
    }

回复收藏 0 原文

水水月牙 2024-10-17 03:48:25

获取用户类型的集合：

var collection = db.GetCollection<User>("users");

如下初始化字段 _id：

var user = new User
{
   _id = ObjectId.Empty,
   Name = "Sam",
   Addresses = (new Address[] { new Address { House = "BIGHOUSE", Street = "BIGSTREET" } })
};

然后插入对象：

collection.InsertOne(user);

_id 字段将自动生成。

在此链接中，您将找到自定义的替代方法自动生成的 ID。

Get the collection as User type:

var collection = db.GetCollection<User>("users");

Initialize the field _id as follows:

var user = new User
{
   _id = ObjectId.Empty,
   Name = "Sam",
   Addresses = (new Address[] { new Address { House = "BIGHOUSE", Street = "BIGSTREET" } })
};

Then you insert the object: