提前感谢您的帮助和关注！
我的项目仅用于学习目的，我对 DDD 完全感到困惑，并且有以下情况：
在我拥有用户和文档的领域中，有一种无处不在的语言。它说：
- A user can create a document. One of the main purpose of my project is to provide users an ability to create different documents. I mean that the documents cannot exist without the users. So,I think that the process of a document creation belongs to my domain.
- A user can send a document for approval. It's one more thing that belongs to the domain. An approval process is one of the most important part of the project. It has its steps that other users must confirm.
- A user can approve a step of approval process.
- A user can reject a step of approval process.
这足以理解和回答我的问题：
用户可以包含以下方法是否正常：CreateDocument(params)、SendDocumentForApproval(docId)、ApproveApprovalStepOfDocument(stepId)？
我对它感到困惑，因为它在代码中看起来有点奇怪。
例如，对于文档创建过程，我们有类似的东西：
public async Task<bool> CreateDocumentCommandHandler(CreateDocumentCommand command)
{
//We have our injected repositories
User user = await _userRepository.UserOfId(command.UserId);
Document document = User.CreateDocoment(command.*[Params for the document]);
_documentRepostiory.Add(document);
// It raises event before it makes a commit to the database
// It gets event from an entity. The entity keeps it as readonly collection.
// Here it raises DocumentCreatedEvent. This event contains logic which concerns
// creation some additional entities for the document and log actions.
await _documentRepository.UnitOfWork.SaveEntitiesAsync();
}
审批流程：
//The first try out to model this process:
public async Task<bool> SendDocumentForApprovalCommandHandler(SendDocumentForApprovalCommand command)
{
//We have our injected repositories
User user = await _userRepository.UserOfId(command.UserId);
//Here I have some problems.
//Is it okay that the method returns the document?
//The method that is placed inside the User has this logic:
//public Document SendDocumentForApproval(int docId)
//{
// Document document = this.GetDocument(docId);
//
// //Inside this method ChangedStatusToApproving is created
// document.SetStatusToApproving();
// return document;
//}
Document document = User.SendDocumentForApproval(command.DocId);
_documentRepostiory.Upadate(document);
// It raises event before it makes a commit to the database
// It gets event from an entity. The entity keeps it as readonly collection.
// Here it raises ChangedStatusToApproving. This event contains logic which concerns
// creation some additional entities for the document and log actions.
await _documentRepository.UnitOfWork.SaveEntitiesAsync();
}
//Is it okay to do something like the command handler above?
//The second one:
public async Task<bool> SendDocumentForApprovalCommandHandler(SendDocumentForApprovalCommand command)
{
//We have our injected repositories
User user = await _userRepository.UserOfId(command.UserId);
//The same one as we have in the previous method.
//But here I don't want to put the logic about the changing status of the doucnent inside it.
Document document = User.SendDocumentForApproval(command.DocId);
//I see that it breaks the method above (SendDocumentForApproval)
//Now It doesn't mean anything for our domain, does it?
//It is only getter like User.GetDocument or we can even do it
//by using repository - documentRepository.DocumentOfId(docId)
document.SetStatusToApproving();
_documentRepostiory.Upadate(document);
await _documentRepository.UnitOfWork.SaveEntitiesAsync();
}
// So, I think the first one is better, isn't it? It follows the ubiquitous language.
//And here is the final question: Why can't I do it like this:
public async Task<bool> SendDocumentForApprovalCommandHandler(SendDocumentForApprovalCommand command)
{
//Here we don't want to use the userRepository. We don't need at all
//Here as a consequence we also don't need a user entity
//Everything what we need is:
Document document = _documentRepository.DocOfId(command.DocId);
document.ForApproval();
_documentRepostiory.Upadate(document);
await _documentRepository.UnitOfWork.SaveEntitiesAsync();
}
//I think that the last approach breaks the ubiquitous language and we're about to having an anemic model.
//But here we have only two queries to the database because we don't need a user.
//Which of the approaches is better? Why? How can I do it more correctly if I want to apply DDD?
我想更详细地解释我的想法。让我们看看用户。他们管理文件。没有用户，文档就无法存在。这是否意味着用户是一个聚合根，我们需要创建、更新、删除它的聚合。
并且该文档也是一个聚合根，因为它包含一个批准过程。没有文档，ApprovalProcess 就不能存在。
这是否意味着我需要做这样的事情：
public async Task<bool> SendDocumentForApprovalCommandHandler(SendDocumentForApprovalCommand command)
{
Document document = _documentRepository.DocumentOfId(command.DocId);
document.SendForApproval();
_documentRepository.SaveChangesAsync();//Raise a domain event - SentDocumentForApprovalEvent
}
// Here we have a handler for the event SentDocumentForApprovalEvent
public async Task SentDocumentForApprovalEventHandler(SentDocumentForApprovalEvent sentDocumentForApprovalEvent)
{
//Now I want to create an approval process for the document
//Can I do the next thing:
ApprovalProcess process = new ApprovalProcess(sentDocumentForApprovalEvent.DocId);
_approvalProcessRepository.Add(process);
_approvalProcessRepository.SaveEntitiesAsync();//Raise a domain event - InitiatedApprovalProcessEvent
//Or Should I create the approval process through Document?
//Looks terrible due to we need to call the repostiory amd
ApprovalProcess process = Document.InitiateApprovalProcess(sentDocumentForApprovalEvent.DocID);//Static method
_approvalProcessRepository.Add(process);
_approvalProcessRepository.SaveEntitiesAsync();
//log
}
// Here we have a handler for the event InitiatedApprovalProcessEvent
public async Task InitiatedApprovalProcesEventHandler(SentDocumentForApprovalEvent sentDocumentForApprovalEvent)
{
//The same question as we have with handler above.
//Should I create steps trough the approval process or just with the help of constructor of the step?
//log
}
非常感谢你，对我糟糕的英语感到抱歉！此致