[GIS] Appending field from file geodatabase table to polygon feature class

Question

I have an existing polygon feature class with about 30 attribute fields. I would like to append another 20 fields from an existing table in the same file geodatabase. Can this be done using an out-of-the-box tool? This is not a problem when creating a new feature class; in this case I would use the Import button on the Feature Class Properties:Fields tab. Now that my feature class contains records (as well as a subtype field with subtypes, in case this makes a difference) the Import button is unavailable (dimmed).

Answer 1

If you want both the fields and their values, you can use Join Field to accomplish this:

Joins the contents of a table to another table based on a common attribute field. The input table is updated to contain the fields from the join table. You can select which fields from the join table will be added to the input table.

_{(source: arcgis.com)}

If you just want the field definitions and no values to be added to an existing feature class, as far as I can tell no out-of-the-box tools will handle this.

However you might be interested in X-Ray for ArcCatalog. It might be able to do what you're looking for ("Merge two different designs in to a new consolidated geodatabase design"), but haven't used it enough myself to say for sure.