Page 135 - DCAP304_DCAP515_SOFTWARE_PROJECT_MANAGEMENT

Unit 6: Effort Estimation

 External Inquiry (EQ): An elementary process with both input and output components that Notes
result in data retrieval from one or more internal logical files and external interface files. The
input process does not update any Internal Logical Files, and the output side does not contain
derived data. The graphic below represents an EQ with two ILF’s and no derived data.

 Internal Logical Files (ILF’s): A user identifiable group of logically related data that resides
entirely within the applications boundary and is maintained through external inputs.

 External Interface Files (EIF’s): A user identifiable group of logically related data that is
used for reference purposes only. The data resides entirely outside the application and is
maintained by another application. The external interface file is an internal logical file for
another application.

After the components have been classified as one of the five major components (EI’s, EO’s, EQ’s,
ILF’s or EIF’s), a ranking of low, average or high is assigned. For transactions (EI’s, EO’s, EQ’s)
the ranking is based upon the number of files updated or referenced (FTR’s) and the number of
data element types (DET’s). For both ILF’s and EIF’s files the ranking is based upon record
element types (RET’s) and data element types (DET’s). A record element type is a user recognizable
subgroup of data elements within an ILF or EIF. A data element type is a unique user recognizable,
non recursive, field.
Each of the following tables assists in the ranking process (the numerical rating is in parentheses).
For example, an EI that references or updates 2 File Types Referenced (FTR’s) and has 7 data elements
would be assigned a ranking of average and associated rating of 4. Where FTR’s are the combined
number of Internal Logical Files (ILF’s) referenced or updated and External Interface Files referenced.

Did u know? What is Internal Logical Files?
ILF stands for “Internal Logical File”. In my words, ILFs represent data that is stored and
maintained within the boundary of the application you are counting. When counting ILFs
you are basically counting the data functions that your application is being built to maintain.

EI Table

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