The Five Major Components - Practices

Function Point Analysis breaks the systems down into smaller components so that users, developers, and managers can easily understand the functionality of a system; the technical knowledge is not required for the same. In the world of function points, systems are divided into components.

Transactional Functions:

The first three components are the systems External Inputs (EI), External Outputs (EO), and External Inquiries (EQ). Each of these components adds, modifies, deletes, retrieves or processes information contained in the files and hence called transactions.

Data Functions:

The other two components are the system’s files viz., Internal Logical Files (ILF) and External Interface Files (EIF).

Transactions in Detail:

External Inputs – This defines those data that interact with the application from the outside. This data from the outside may be used to maintain internal logical files.

External Outputs – Here, the data passes from inside the application to the outside. The derived data may be used to update internal logical files. The data is used to create reports or output files which, in turn, may be used by other applications. These reports are again created from internal logical files or external interface files.

External Inquiry – This contains both input and output components that retrieve data from internal logical files and external interface files. However, the input here does not update the internal logical files or external interface files as in external inputs, and the output does not contain derived data as in external outputs.

Data Functions in Detail:

Internal Logical Files – This contains logically related data that resides entirely within the application’s boundary and is maintained through external inputs.

External Interface Files – This contains logically related data that is used for reference purposes only. The data resides entirely outside the application and is maintained by another application. This means that an external interface file can be an internal logical file of another application.