There are some restrictions for selecting the secondary tables and fields of a maintenance view or help view.

• The secondary tables have to be in an n:1 dependency to the primary table or directly preceding secondary table. This is the case if the secondary table is the check table of the base table. If the base table is the check table, then the foreign key fields have to be key fields of a text table or the foreign key must have cardinality n:1 or n:C.

• All key fields of the primary table must be included in a maintenance view. In addition, all key fields from foreign key tables which are not involved in the foreign key (that is, which are not linked via a join condition to a key field already included in the view) must be included in the view.