Subrecords Do Not Have to Be Explicitly Saved
In SuiteScript 1.0, you had to explicitly save a subrecord prior to saving the record. However, in SuiteScript 2.0, after you create a subrecord or make changes to one, you are not required to explicitly save the subrecord (and no methods exist for that purpose). Your new subrecord is saved at the time you save the record. The same rule applies if you make changes to an existing subrecord. Your updates are saved at the time you save the record.