Database Elaborations: Digging Deeper into Many-To-Many Relationships

An inherent awkwardness exists in every many-to-many relationship between entities. Ambiguity causes this persistent awkwardness, primarily because a many-to-many relationship is such a fuzzy thing. In data discovery, encountering many-to-many relationships may actually expose a level of disregard about details by the subject matter experts.

For example, if one must model parents and children, initially a many-to-many relationship exists between a Parent entity and a Child entity. One Parent instance could be "John" and another "Mary." Both "John" and "Mary" are the parents of "Sam," "Suzy," and "Mike," where each represent Child instances. While the possibility to do so does exist, rarely should one find it sufficient to simply make these statements: "John is parent to Sam"; "Mary is parent to Sam"; "John is parent to Suzy"; "Mary is parent to Suzy"; "John is parent to Mike"; and "Mary is parent to Mike." A more nuanced and detailed description of these interrelationships supports informational needs, and how these descriptions evolve affects the manner in which each data model focuses on an organizational set of needs and differs from other such needs.

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