使用NHibernate的深层复制实体

Question

I am currently starting a new ASP.NET MVC Project at work where we need to generate a project cost estimate.

We are using NHibernate, ASP.NET MVC 1.0 and StructureMap.

The client wants to be able to fill all the information about the project, the information is in different pages and we need to persist in between each post back.

The client does not want to have the option to Save it under a name when it is completed, but we want to persist it in the database even when he did not save it yet. So we had the idea to create a "Draft mode", so the user will start working on his project, will fill all the pages, and it will be persisted in the database with the "Draft mode" on.

But we need to manage the drafts, I mean, when the user will start editing an existing project, we will need to create a copy of it, set the object and all its childs to Draft mode and create a copy of it in our database. We will need to alter all the references from the childs.

So, I am trying to find the best way to deep copy the objects and alter all the references, I would prefer to do not have to create a copying class for every entity that I will have to copy, maybe something more generic if this is possible.

Please let me know if you need more details or if something is unclear.

Thanks,

Charles

Answer 1

I would try to have my domain solve this issue and leave NHibernate to just saving the data instead of copying it. I would create an IDeepCopy interface that defines a DeepCopy() method. And then in each of these method you would create a new object and just copy the values yourself and control how you want to handle children or parent objects correctly.

Answer 2

这可能是个坏主意，我不确定它是否会起作用，但是如果你只是通过对象图并将所有必需的id设置为默认的未保存值然后让级联保存将所有引用拼接回来的工作怎么办？在数据库中。

Answer 3

I recommend to use SharpArchitecture for your project. It'll save you a lot of time and money.
There are no easy way to do a deep copy of data because it's very specific to a case. So you have to create all copies manually.
I also recommend to use different tables for draft entities and not draft ones. IMO in this case it'll be much more easier to implement and it doesn't violates with SRP . As it was said, divide and rule.

Answer 4

I use this function:

    public static T DeepClone<T>(T obj)
    {
        using (var ms = new MemoryStream())
        {
            var formatter = new BinaryFormatter();
            formatter.Serialize(ms, obj);
            ms.Position = 0;

            return (T)formatter.Deserialize(ms);
        }
    }