Question

我有一个小问题如何存储包含另一个对象的对象？例如

对象人物

Person { Name, Mother }

其中母亲是同一类人物的另一个对象

希望得到帮助 lczernik

Answer 1

class Person
{
    public string Name;
    public Person Mother;
    Person (string name, Person mother)
    {
        Name = name;
        Mother = mother;
    }
}

像

一样使用它

Person me = new Person("user2069747", new Person("user2069747's mom name", null));
// null was used because you may not know the name of your grand mom;
Console.WriteLine(me.Name) // prints your name
Console.WriteLine(me.Mother.Name) // prints your mom's name

Answer 2

db4o将自动为您存储整个对象图，但是，由于性能优化，您需要注意以下场景：

对象检索
对象更新

在这两种情况下，db4o都会执行请求某些深度的操作，通过以下配置参数进行设置：

因此，给定以下模型，您可以将对象图存储在一次调用中：

using System;
using Db4objects.Db4o;

namespace Db4oSample
{
    class Person
    {
        public string Name { get; set; }
        public Person Mother { get; set; }

        public override string ToString()
        {
            return Name + (Mother != null ? "(" + Mother + ")" : "");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var grandMother = new Person {Name = "grandma"};
            var mother = new Person {Name = "mother", Mother = grandMother };
            var son = new Person {Name = "son", Mother = mother};

            using(var db = Db4oEmbedded.OpenFile("database.odb")) // Closes the db after storing the object graph
            {
                db.Store(son);
            }

            using(var db = Db4oEmbedded.OpenFile("database.odb"))
            {
                var result = db.Query<Person>(p => p.Name == "son");
                if (result.Count != 1)
                {
                    throw new Exception("Expected 1 Person, got " + result.Count);
                }

                Console.WriteLine(result[0]);
            }
        }
    }
}

希望这有帮助

如何存储包含对象的对象

2 个答案: