Resolve many-to-many relationships.
A many-to-many relationship can be modeled, however, it cannot be implemented in a relational database because it violates data integrity. A many-to-many relationship is reduced to two one-to-many relationships with an intersecting entity. Create a new entity that is positioned between the existing two entities.
Resolution is accomplished by following these steps:
- Determine the name of an intersecting entity (name using a combination of the two many-to-many names if necessary).
- Define the first one-to-many relationship and put the many on the intersecting entity.
- Add the other relationship (which should be the original relationship between the two entities without the cardinality). Define the second one-to-many relationship, again with the many on the intersecting entity.