Error: Redefinition of field

When you are working on a LookML file, you might come across an error in the form Redefinition of field 'view_name.field_name' after you validate your code with the Content Validator.

The error will appear under LookML Errors in the Project Health Panel after the LookmL validator is run.

This page will help you understand the error's meaning, common causes, and how to troubleshoot.

Common causes of Error: Redefinition of field

The error Redefinition of field 'view_name.field_name' means that Looker has identified two fields with exactly the same combination of view and field names.

There are several common causes of the error:

  • You have accidentally named two fields with the same name in the same view. This could be:
    • Two dimensions with the same name
    • Two measures with the same name
    • One dimension and one measure with the same name
  • You copied and pasted a field in a view and forgot to change the name.
  • You joined a view to your Explore a second time but forgot to give the join a different name.
  • You used the LookML generator to create your LookML project and created duplicate fields.

    For example, you use the LookmL generator and your data table has a column named count. In this case, Looker will create a dimension named count, which references the column in your table. By default, Looker will also create a measure named count (which is the only default measure that Looker creates). Since the two fields are both named count, the error occurs.

The next section of this page will help you identify the view in your LookML project that is the source of the error.

Finding the view mentioned in the error

Keep in mind that the view name that is mentioned in the error will be the view name as it is defined in the explore parameter where the view is joined.

For the typical case, the view name is easy to understand. For example, you could have the following join: 

join: address
foreign_key: order.billing_id

In this example, the view name that is mentioned in the error is address, as specified in the join parameter.

Finding the source view when a view name is aliased in a join

If you are using an alias to change the way a view name is displayed in a join, the alias name will be mentioned in the error message. For example, suppose you have a join using the from parameter. The from parameter lets you give the join a different name than the underlying view, which is useful when you want to join the same view a second time. 

join: billing_address
from: address
foreign_key: order.billing_id

In this example, the view name that is mentioned in the error from the LookML view file will be billing_address and not address.