Software Architecture Patterns, 2nd Edition

Chapter 3. Layered Architecture

The most common architecture style is the layered architecture, otherwise known as the n-tier architecture. This style is the de facto standard for most applications because it aligns with traditional IT team structures where teams are organized by technical domains (such as presentation teams, backend development teams, database teams, and so on). Because it is so widely known by most architects, designers, and developers, the layered architecture is a natural choice for most business application development efforts. However, like all architecture styles, it has its strengths and weaknesses and is not always suitable for some systems.

Description

Components within the layered architecture style are organized into horizontal layers, each performing a specific role within the application (such as presentation logic, business logic, persistence logic, and so on). Although the number of layers may vary, most layered architectures consist of four standard layers: presentation, business, persistence, and database (see Figure 3-1). In some cases, the business layer and persistence layer are combined into a single business layer, particularly when the persistence logic (such as SQL) is embedded within the business layer components. Thus, smaller applications may have only three layers, whereas larger and more complex business applications may contain five or more layers.

Figure 3-1. The layered architecture style is a technically partitioned architecture ...