Specifies the behavior when this attribute is updated as part of an 'update' operation such as UpdateItem. See
documentation of
UpdateBehavior
for details on the different behaviors supported and the default behavior.
For attributes within nested objects, this annotation is only respected when the request uses
IgnoreNullsMode.SCALAR_ONLY
. In
IgnoreNullsMode.MAPS_ONLY
or
IgnoreNullsMode.DEFAULT
,
the annotation has no effect. When applied to a list of nested objects, the annotation is not supported,
as individual elements cannot be updated — the entire list is replaced during an update operation.