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).

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  • Do you just want the field definitions to be added or the data contained within them as well? How are the two tables related (primary/foreign key) and is it a one-to-one, one-to-many, etc. relationship? Have you considered using a join instead of adding the fields permanently?
    – blah238
    Commented Oct 19, 2012 at 18:44
  • This feature class must remain a flat structure. I just want to add the fields from another existing table. Commented Oct 19, 2012 at 18:58
  • "I just want to add the fields from another existing table." That still does not help to clarify my first question. Presumably you want the data contained within the fields as well, no?
    – blah238
    Commented Oct 19, 2012 at 19:02
  • no data, just the fields. Commented Oct 19, 2012 at 19:13
  • AFAICT, no out of the box tools will let you copy just the field definitions to an existing feature class (other than the Import button you mentioned, which only works on empty feature classes). You could use Python to accomplish this pretty easily though if you are interested in such a solution.
    – blah238
    Commented Oct 19, 2012 at 19:24

1 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.

Join Field
(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.

  • Thanks. I have 3 primary ID's (a combination of which is unique, some exist some don't, in some cases there are none if the particular property was not yet processed) I want a flat structure for this particular feature class. Commented Oct 19, 2012 at 18:56
  • That sounds similar to their second example (using Table to Table with a field map to concatenate fields before using Join Field).
    – blah238
    Commented Oct 19, 2012 at 19:04

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