I am trying to set up a quick model that:

  1. Takes a point feature layer of development projets (a table in an access database with xy coordinates),
  2. Spatially joins polygon neighborhood designations to the feature layer,
  3. Join the output of 2 to the source feature layer (sitting as a table in access)
  4. Updates the neighborhood field based on the neighborhood field from the attributes from the spatial join

The point is that I really don't want to create a new file every time I do this, but maintain and add to the existing table of development projects.

My question is how to properly qualify field names in the field calculator so I can update values in the source table (1) based on the values of the spatial join featureclass with the neighborhood designation (2). I join the output of (2) to (1) so the attributes should all be in the same name space, I imagine.

I currently use this as my update expression (VB parser):


A field name was not found or there were unbalanced quotation marks.
ERROR 999999: Error executing function.
Item not found in this collection.
Failed to execute (Calculate Field).

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1 Answer 1


In your expression, just use:


It is incorrect to specify an assignment in the expression. You specify which field you are calculating in the 2nd parameter of the Calculate Field tool.

On another note I would suggest moving over to Python as it is better documented in the help and supports geoprocessing functions and objects which VBScript doesn't.

Rewritten in Python:


See Using the Calculate Field Tool in the documentation.

  • Of course. Thanks for pointing out the assignment issue.
    – ako
    Commented Aug 12, 2011 at 6:46

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