Apply DQ rule on a boolean type

Not sure if I understand the question properly @Gerson, however:

1. If you are trying to check if the values of the column contains only either “Ja” or “Nee”, then this Advanced Expression should work for you:

   (INPUT is in {"Ja", "Nee"})

   

2. If the column doesn’t contain strings “Ja” or “Nee”, but rather values expressing logical TRUE and FALSE (column of a boolean type), then this should work for you:

   (INPUT is in {TRUE, FALSE})

   

You can see more in the documentation:

1. Data Quality rules
2. ONE Expressions (Advanced Expressions)