Generally a many-to-many relation between two data tables forms a third table which contains the primary key of both tables. For instance, if there are two table or data entity, named “Person” and “Address”, and if there is a relation between these entities is “many to many”, there would be another table, which will keep this relation in the table, which could be named as “Person-Address”. Some logical model supports to create a separate logical entity in application layered components (DAL, BLL, BE etc) for the many-to-many table, and some application embeds the operations in the logical entity of any of the two primary tables.