Overview of Architectural Thinking and Layered Architecture Models

Architectural thinking combines system thinking, structured thinking, and programming thinking, serving as a bridge between real‑world business and abstract IT implementations; its core is to let business drive technology and ensure technology ultimately serves the business.

The two key focuses in architecture are decomposition and integration: decomposition breaks complex problems into cohesive, loosely‑coupled parts while clearly defining requirements, and integration connects these parts through appropriate interfaces to form a complete whole.

When planning a large‑scale architecture, the cloud computing three‑layer model (IaaS, PaaS, SaaS) is often referenced: the IaaS layer handles physical and virtual infrastructure, the PaaS layer provides platform services (including emerging business platforms or middle‑office layers), and the SaaS layer delivers specific applications.

In addition to the cloud model, a service‑oriented architecture (SOA) introduces a three‑layer view of resources, services, and applications, highlighting an independent service layer that exposes capabilities via APIs and can be further divided into component, service, and process layers.

Application architecture commonly follows the classic three‑tier pattern—User Interface, Business Logic, and Data Access—while domain‑driven design adds an Application layer and renames Business Logic to Domain layer and Data Access to Infrastructure layer, enabling clearer separation of concerns.

Various architectural diagrams illustrate how these layers can be combined, such as the cloud‑SOA hybrid model where resource, service, and application layers are nested, and the detailed breakdown of technical stacks for big‑data platforms or micro‑service ecosystems.

Finally, the article outlines practical guidance for constructing architecture diagrams, recommending the use of consistent layering standards (cloud three‑layer, SOA three‑layer) and separating concerns like security, quality, and standards into peripheral sections while focusing the central view on resource, platform, and application layers.