Data Transformation Engine Map Designer Reference Guide

Chapter 8 - Functional Map Basics Syntax of a Functional Map Expression
Map Designer Reference Guide
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Each of these expressions evaluates to data. For example, the following
expression evaluates to the data object FixedRecord:
FixedRecord:Input
The following expression evaluates to StoreInfo data objects:
EXTRACT (StoreInfo:Inventory, StoreName:Inventory = “Lee
Furniture”)
The INDEX (Record:File) expression evaluates to an integer.
The
“Mercator” expression evaluates to text.
For a detailed discussion of functions and expressions, see the Functions and
Expressions Reference Guide.
Determining the Arguments of a Functional Map
The input arguments of a functional map are the objects necessary to create one
occurrence of the output object where the map rule is.
To determine what the input argument(s) of a functional map should be, ask
yourself, “What do I need to create this output?” Whatever is necessary in a
functional map must be passed to it as an argument. There may be one or more
input arguments. The arguments of a functional map can be thought of as
triggers. The number of times a functional map is triggered depends on the
number of occurrences of the input arguments in the data and the expressions
used for each argument.
Note To determine the input arguments of a functional map, ask yourself what objects
are necessary to create one occurrence of the output object.
If an Input Argument to a Functional Map Evaluates to NONE
If an occurrence of input argument is missing, the functional map is not evaluated.
A file that has no content will still allow the functional map to execute.
For example, in the following functional map expression:
MakeForm (EntryForm:Input, GroupInfo:Input)
the GroupInfo object is optional with a component range of (0:3).
If there are no occurrences of GroupInfo in the source data object, the specified
MakeForm functional map is not evaluated.