关于Component Diagram中同主机内部数据库表示方式的技术咨询

Great question! This is a common point of confusion when building component diagrams, and the answer boils down to two key considerations: the level of detail you need to communicate, and the architectural significance of the database to your system.

When to Represent It as a Separate Component #

• If your application treats the database as a distinct logical service (even if it’s on the same host), go with a separate component. This is especially true if:
  • You might split the database onto its own host in the future (even hypothetically)
  • Other components (even running locally) interact directly with the database
  • You need to make explicit dependencies clear to your audience (developers, architects, stakeholders)
• Label it something like Internal Database and define its interface (e.g., Database CRUD API) to show how your application component interacts with it.

When to Embed It in the Main Application Component #

• If the database is a purely internal implementation detail with no external interactions or future separation plans, you can include it within your main application component. For example:
  • A local SQLite database that only this specific app instance uses
  • A database that’s tightly coupled to the app’s code and can’t function independently
• In this case, you can note the database in the component’s description or interface documentation (e.g., MyApp - Includes embedded SQLite database) instead of drawing a separate box.

Key Takeaway #

The priority is clarity for your audience. If the database’s existence and interactions are relevant to understanding the system’s architecture, make it a separate component. If it’s a hidden detail that doesn’t impact the overall design, embedding it is perfectly acceptable.

内容的提问来源于stack exchange，提问作者Amr Saeed