Description

We've noticed that if a holdings record is updated (e.g. add 866 $a summary holdings) in the Metadata Editor (MDE), all of the holding’s linked items also updated with the same modification date, even if untouched. 
We also notcied that this doesn't happen if the holdings record is updated via a job. 
I ran an Analytics report of cases where Item Modification Date is earlier than the Holdings Modification Date (i.e. item didn't update at the same time as the holdings). 
The only time this happened is when the holdings was updated by the System. 
Why does the item modification date change, but the reason for the change doesn't display anywhere (e.g. Item Hisotry, Analytics, etc.)? 

Resolution

Not every change to an item field is reflected on the item history tab, i.e. 866 changes.
When you save a holding record, all the items under this holding will be re-saved. 
In this case there is no change to the item record, but the item re-save is included in the holdings record save process.
When the holding record is saved by the "system" (via a job) the item is not re-saved automatically. 
The holdings modification date is later than the item modification date because it was saved by the system (not manually by a user).
Since the item re-save does not change any item record data, it doesn't appear in the Item History tab.
Note that the Item's modification date will likely be updated if predicted items are opened from the holdings record.

Additional Information

Working with Holdings Records

Working with Items

Create Summary field 866/867/868 

Automatic Generation of the Summary Holdings Statement Based on Items

• Article last edited: 23-July-2021