The following four layers are the most common layers in a logical multilayered architecture for an information system with an object-oriented design:
- Presentation Layer (a.k.a. UI Layer, View Layer, Presentation Tier.)
- Application Layer (a.k.a. Service Layer or GRASP Controller Layer )
- Business Layer (a.k.a Business logic layer (BLL))
- Infrastructure Layer (Data access layer, Persistence layer, Logging, Networking, and other Services which are required to support a particular Business Layer.)
Some common purposes of the above four layers are for example described in the book about domain-driven design at page 68-74, which is a book that otherwise is focused on describing the Domain layer
Sometimes there is no explicit distinction between the Business Layer and the Application Layer, e.g. the Application Layer is considered as being a part of the Business Layer. On the other hand, it is also possible to even further divide the Application/Business Layers into more layers. For example, if the Model View Presenter pattern is used, then you can consider the Presenter Layer as being a layer between the User Interface Layer and the Application Layer.
The Business Layer can also use a Business Infrastructure Layer (aka low-level business 'services' layer) logically positioned between Business Layer(s) and Infrastructure Layer(s). That layer (BI) is very general and can be used in several application tiers, e.g. a CurrencyConverter.
The Infrastructure Layer may be partitioned into different levels (high-level or low-level technical services). Though, it is not unusual that developers only consider the persistence (data access) and therefore only talk about the Persistence Layer or the Data Access Layer (instead of an Infrastructure Layer or Technical services Layer). In other words, the other kind of technical services are not always being explicitly thought of as being part of any particular layer.
Regarding that all types are not always considered as belonging to one particular layer, according to the "POSA book" (Pattern-Oriented Software Architecture A System of Patterns, page 39) a relaxed layered system (as opposed to a strict layered system) can use so called "shared data definition modules" which are types not belonging in a particular layer.
Famous quotes containing the words common, layers, information, system, logical and/or architecture:
“The difference between human vision and the image perceived by the faceted eye of an insect may be compared with the difference between a half-tone block made with the very finest screen and the corresponding picture as represented by the very coarse screening used in common newspaper pictorial reproduction. The same comparison holds good between the way Gogol saw things and the way average readers and average writers see things.”
—Vladimir Nabokov (1899–1977)
“The force of a death should be enormous but how can you know what kind of man you’ve killed or who was the braver and stronger if you have to peer through layers of glass that deliver the image but obscure the meaning of the act? War has a conscience or it’s ordinary murder.”
—Don Delillo (b. 1926)
“Phenomenal nature shadows him wherever he goes. Clouds in the staring sky transmit to one another, by means of slow signs, incredibly detailed information regarding him. His inmost thoughts are discussed at nightfall, in manual alphabet, by darkly gesticulating trees. Pebbles or stains or sunflecks form patterns representing in some awful way messages which he must intercept. Everything is a cipher and of everything he is the theme.”
—Vladimir Nabokov (1899–1977)
“The twentieth-century artist who uses symbols is alienated because the system of symbols is a private one. After you have dealt with the symbols you are still private, you are still lonely, because you are not sure anyone will understand it except yourself. The ransom of privacy is that you are alone.”
—Louise Bourgeois (b. 1911)
“It was at that moment, just after Krug had fallen through the bottom of a confused dream and sat up on the straw with a gasp—and just before his reality, his remembered hideous misfortune could pounce upon him—it was then that I felt a pang of pity for Adam and slid towards him along an inclined beam of pale light—causing instantaneous madness, but at least saving him from the senseless agony of his logical fate.”
—Vladimir Nabokov (1899–1977)
“I don’t think of form as a kind of architecture. The architecture is the result of the forming. It is the kinesthetic and visual sense of position and wholeness that puts the thing into the realm of art.”
—Roy Lichtenstein (b. 1923)