Which transformers can set an attribute value only if that attribute does not already exist?

• A. AttributeCopier only
• B. AttributeRenamer only
• C. Both AttributeCopier and AttributeRenamer
• D. Neither

Answer: (C)

The idea being tested is non-destructive attribute creation: setting a value only when that attribute isn’t already present. In FME, both the AttributeCopier and the AttributeRenamer can be configured to avoid overwriting existing attributes, so they can establish a value only if the attribute does not yet exist.

With the AttributeCopier, you map a source attribute to a destination name in a way that creates the destination attribute when it’s missing, and you can ensure that you don’t overwrite an existing destination attribute. This lets you supply a default or fallback value only when the attribute isn’t already defined.

With the AttributeRenamer, you move or promote a value to a new attribute name. If the target name doesn’t exist, the operation creates that attribute; if the target already exists, you can choose to skip or avoid overwriting, effectively setting the value only when the attribute is not present.

So both transformers can achieve the behavior of setting an attribute value only if that attribute does not exist.