How do I find the layer ID for attachment tables

[BrandonGuo]

I have a feature service that I need to edit through ArcGIS Pro. I am trying to overwrite the web layer, and I need to ensure the layer ID is the same as the existing feature service. 

However, the attachment table is only visible through the file geodatabase, and I can't find the original table within ArcGIS online. How do I know if I am assigning the correct layer ID when overwriting? Or the layer ID doesn't matter for attachment tables? 

Also, do I need to include the GDB_ServiceIteams table while overwriting the web layer?

All tables from the downloaded geodatabase.

Layers I need to include when overwriting. 

Layers are visible through ArcGIS online.

[David_Brooks]

@BrandonGuo the attachments are linked to the features using the GLOBALID which is an uneditable system field. So any editing you do to the attributes will not affect attachments. 

If you open the properties of the ATTACHREL file in catalog, you can see that the GLOBALID of each feature is linked to an ID field in the attachment table called RELGLOBALID or something like that. And each attachement then also has its own unique GLOBALID as well. Can be a buit confusing, but it works!

You don't need the GDB_ServiceItems file, just ignore it. If you've downloaded a feature service locally to edit, you can overwrite after with njo issues, but the easiest and safest way to perform offline edits is to download the map using the map download tool within Pro, which you can then sync afterwards:

https://pro.arcgis.com/en/pro-app/latest/help/projects/take-a-map-offline.htm 

[BrandonGuo]

Thank you, @David_Brooks . I'll remove the GDB_ServiceItems file. 

I am trying to add contingent value to the feature service; offline map might not be the right option. 

It seems like the layer ID for attachment tables doesn't matter when uploading. All linked with GLOBALID, the sequence of the layer doesn't impact the link.