Question

阅读CLCS时,有很多人谈到电子邮件通知,想从哪里获得数据。 Imagine a senario, 一名用户邀请其他用户参加一次活动。为了通知用户他已被邀请参加某项活动,他收到电子邮件。

具体步骤可能类似:

A CreateEvent command with an associated collection of users to invite, is received by the server.
A new Meeting aggregate is created and a method InviteUser is called for each user that is to be invited.
Each time a user is invited to an event, a domain event UserWasInvitedToEvent is raised.
An email notification sender picks up the domain event and sends out the notification email.

现在我的问题是: 我在什么地方要把信息列入电子邮件?

Say,我想介绍活动以及用户名称。既然是CQRS,我就能够 t弄我的领域模式;所有领域物体的特性都是私人的! 那么,我是否应该问一下: 或者将电子邮件通知完全转移到另一个部门?

Answer 1

在CLCS,你将指挥与盘问方面重新分开。你们总是想去问答,以便获得某个活动手的数据。书面数据库将是一个单独的数据库,其中包含建立您域名所需的数据,不会优化成文,而是书面数据。

The domain should register and send an EventCreated event to the event handlers / processors. This could be raised from the constructor of the Meeting aggregate.
The event processing component would pick up the EventCreated event, and update the query database with the data contained in the event (ie, the Id of the event and its name).
The domain could register and send a UserWasInvitedToEvent event to the event processors.
The event processors would pick up the UserWasInvitedToEvent and update the query store with any reporting data necessary.
Another event processing component would also pick up the UserWasInvitedToEvent event. This process could have access to the query database and pull back all of the data necessary for sending the email.

查询数据库只不过是一个报告数据库,因此,你甚至可以有一个具体表格,储存电子邮件所需的全部数据。