domain-driven-design - CQRS 中的聚合

Question

什么是聚合以及它们如何在 CQRS(命令-查询-责任-隔离)和 ES(事件溯源)中使用？我是这种架构的新手，如果有人可以向我解释这一点，我会非常高兴。谢谢!

Answer 1

首先我想引用 Martin Fowler's blog post on CQRS并注意 聚合与领域驱动设计相关，然后与 CQRS 相关。 .

CQRS naturally fits with some other architectural patterns.

• As we move away from a single representation that we interact with via CRUD, we can easily move to a task-based UI.
• Interacting with the command-model naturally falls into commands or events, which meshes well with Event Sourcing.
• Having separate models raises questions about how hard to keep those models consistent, which raises the likelihood of using eventual consistency.
• For many domains, much of the logic is needed when you're updating, so it may make sense to use EagerReadDerivation to simplify your query-side models.
• CQRS is suited to complex domains, the kind that also benefit from Domain-Driven Design.

就领域驱动设计而言，聚合是实体和值对象的逻辑组，它们被视为单个单元 ( OOP, Composition)。聚合根是所有其他实体都绑定(bind)到的单个实体。