Joins/Field Calcs question... and Export/import Metadata question

[JoshuaDamron]

Background:
When we hire an intern to update feature class data we typically set the intern up with a copy of the data so as to protect the original.  Sometimes the interns work lasts for a few months mean while the original data is otherwise updated by staff.  (An example of this is we had an intern add elevation attributes to sewer manholes and mains in a new field.)  Once the intern is finished, it is necessary to add the new attribute field data to the original feature class. 

The problem at hand:
In my current work flow I am working with an interns point file which has identical geometry to the original, the only area which the intern updated was to add a new attribute field and populate its data.  This is where I'm hoping that I'm missing something simple. 

My understanding of the required workflow:

1) To combine the data I perform a join between the orignal and intern feature classes. I thought I could then create a new field and field calculate the data over via the join.  However I'm realizing this was an incorrect assumption.  Field calculations cannot be performed with joined data.

2) I export the joined data to a new feature class.  This new feature class can now replace the original feature class as it is the final result.

The problem is that when an export is performed the metadata is lost...  to get the metadata:

3) I export the metada from the original feature class

4) Import the metadata into the new feature class. 

5) Not all of the metadata carries over in the export (i.e. Tags, Summary (Purpose), Description (Abstract)).  I now have to either re-create the data missing from the original export or cut & paste it from teh original feature class into another document then cut & paste again into the metada of the new feature class.

My questions:
Am I totally missing something here?  Why do field calculations not work between joins?  Why do these metadata fields not export?  Is there a simpler method to this workflow?

[PaulKroseman · Accepted solution]

You can certainly use field calculator over a join.

Create the field in the main feature class, join the intern's table on your key field, start editing on the main feature class, use field calculator on the new field, select the field from the interns table.

Can't help on the metadata stuff though.

[JoshuaDamron]

Paul,
  Thanks for a solution, I knew there was a simple method I just couldn't think of it at the time...

I'm fairly certain that there is no answer to my metadata question.