You can control how to access a field of a maintenance view with the maintenance attribute. There are the following maintenance attributes:

• R : Only pure read accesses are allowed for such fields. You cannot maintain such fields with Transaction SM30.
• S : These fields are used to create subsets when maintaining view data. Only a subset of the data is displayed. This subset is defined by entering a suitable value in this field.
• H : These fields are hidden from the user in the maintenance dialog. The field does not appear in the maintenance screen. You have to ensure that such fields have the correct contents. By default they are left empty.
• : There are no restrictions for the field maintenance.