The Logical Data Model -

- Is a generic relational schema (in at least 1NF) which -

Propagation of foreign keys may be explicit or implied in a logical data model. As long as the resulting physical schema includes the necessary foreign key columns and joins, the representation of foreign keys in the logical model is a matter of convenience and taste.

Replacing many-to-many relationships with associative entities is necessary to model 1st normal form, support internal attributes and secondary relationships, and enable alternate identifiers.