Certain transforms have multiple datasets as their output instead of a single dataset,
for example, SplitFields. The SelectFromCollection
transform selects one dataset (DynamicFrame) from a collection of datasets (an
array of DynamicFrames). The output for the transform is the selected
DynamicFrame.
You must use this transform after you use a transform that creates a collection of
DynamicFrames, such as:
-
Custom code transforms
-
SplitFields
If you don't add a SelectFromCollection transform node to your job diagram after any of these transforms, you will get an error for your job.
The parent node for this transform must be a node that returns a collection of
DynamicFrames. If you choose a parent for this transform node that returns a
single DynamicFrame, such as a Join transform, your job
returns an error.
Similarly, if you use a SelectFromCollection node in your job
diagram as the parent for a transform that expects a single DynamicFrame as
input, your job returns an error.
