Comparing executable and functional maps

There are two kinds of maps: executable maps and functional maps.
Executable Map
An executable map is a map responsible for the totality of your inputs and outputs. The sources and targets of an executable map are entire files, database tables, messages, applications, and so on. Think of an executable map as the main map, the top-level map. Executable maps are compiled and run.
Functional Map

A functional map is referenced by another map through a map rule. A functional map maps just a portion of the entire data. Data sources and targets are not specified in the cards of functional maps. Functional maps are not compiled and run.

Note: A given map can be used both as an executable and as a functional map. You may want to test small portions of your data and temporarily use a map you created as a functional map as an executable map on that portion of the data.

If a map is used as a functional map, the input data and output data settings specified in that map are ignored.