Function Points FAQs

Handling Shared Files

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Issue Description

General Discussion and Resolution


ISSUE

What factors should be considered when multiple applications share the same logical files?

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GENERAL DISCUSSION AND RESOLUTION

Logical files may be shared between applications. Conceptually, where one application references an ILF owned/maintained by another application, the amount of data being referenced is either:

  • the complete record or
  • a subset of the record

Therefore, the complexity of the EIF cannot be greater than the complexity of the ILF being referenced.

When many projects are being counted, each of which may have different FP Analysts, documentation sets, and application experts, it is possible that files common to more than one application may be inconsistently counted for these applications. A file counted as an EIF should be of the same or lower complexity than the ILF from which it is derived.

FP Analysts are usually aware when the file that they are referencing is maintained by another application. It is recommended that, prior to including the file in their count file list, the file list of the ‘parent’ application be reviewed to determine the System File Id, System File Name and file complexity rating. Where both applications reside in the same FPW database, a ‘Dummy’ transaction can be created in the ‘parent’ application and then copied to the project count in the ‘target’ application. This will ensure that shared files are counted consistently. The System File Name can also be prefixed by the system id of the parent application, if sufficient characters are available within the File Name field. The complexity rating of the file within the ‘target’ application must be reviewed and assessed from the perspective of that application.

Note: 1.When copying the "Dummy’ transaction, don’t forget to "Copy with File Links"

2.Remember to remove the ‘Dummy’ transaction from both the ‘parent’ and ‘target’ function point counts.

The approach is illustrated in the following table:

Application Name

ID

Name

Type

Complexity

Application Alpha

FILE_B

Beta Customer Account

EIF

Avg or Low

Application Beta

FILE_B

Customer Account

ILF

Avg


If the shared file does not currently exist in the ‘parent’ count file list, whenever possible seek the advice of an application expert from the ‘parent’ application before adding the file to your ‘target’ application count.

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Issue Description

General Discussion and Resolution