Function Points FAQs
Handling Shared Files
What factors should be considered when multiple applications share the same logical files?
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:
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: