Restrictions for Maintenance and Help Views 

There are some restrictions for selecting the secondary tables 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 ensures that there is at most one dependent record in each of the secondary tables for a data record in the primary table. In the example below, you can see an example of N:1 dependencies between the primary and the secondary tables.

A N:1 dependency exists if the secondary table is the check table in the foreign key used. If the secondary table is the foreign key table, the foreign key fields must be key fields of a table or the foreign key must have the cardinality N:1 or N:C

See also:

Semantic Attributes of a Foreign Key