The IT view contains the following model types:

In the context of city planning, the current application system hierarchy of a company is depicted using the application system type diagram or the application system type diagram (column display). The application system type diagram (column display) is a lane diagram (diagram in column or row display) that provides precisely those object types, symbols, and relationship types from the application system type diagram that are required for city planning.

The following levels of an application system type hierarchy can be depicted:

IT system, Subsystem, IT software, and IT block are symbols of the Application system type object type. The hierarchy is built using the encompasses relationship type.

IT systems are at the top level of the application system type hierarchy. An IT system is made up of a structured quantity of IT elements, usually subsystems. Administration and operation of an IT system are the task of a specified organizational unit.

A subsystem is a component of an IT system. The components of a subsystem are called IT software.

IT software supports a homogeneous set of functions. It is user-oriented and supports one or more business processes. IT blocks are components of IT software.

Generally, an IT block includes IT procedures that access the same data (databases, tables, files, etc.).

IT procedures are objects of the IT function type type. Each IT procedure supports a specific function.

A socket corresponds to the IS service, i.e., it is an interface that an IT element provides for other IT elements so that these can access the IT element's data and processing methods.

The following figure shows an example of the subsystem structure of the DATEV system: