How to detect and add a missing columns?

Hello @Daniel_Weikert,

domain is the “list of possible values” for a column. If you click the “Spec” tab in an output table, you’ll see the data types of the columns and the domain of the values in the columns. For numerical values, only the range of the values in the data is shown. For string values, the different values appearing in the data are shown (by default up to 60 values but this can be changed; see here how).

This forum topic regarding domain and it’s refreshing is also useful: