ManyToMany mapping describes a relationship between to entities where both can be related to more than one instance of each other, and is defined by the
@OneToMany where a foreign key column in the table of the entity can be used,
ManyToMany requires a join table, which maps the entities to each other.
The topic discusses how you can map one-to-many and many-to-many relationships using Entity Framework Code First.
Most of this documentation implicitly or explicitly applies to GNU Emacs. This may be the most well known variant of Emacs, as well as the source of several forks, and the target of some merges.
This topic discusses some of the variants of Emacs one may encounter, and their primary differences from GNU Emacs.
The idea of one to many (1:M) concerns the joining of rows to each other, specifically cases where a single row in one table corresponds to many rows in another.
1:M is one-directional, that is, any time you query a 1:M relationship, you can use the 'one' row to select 'many' rows in another table, but you cannot use a single 'many' row to select more than a single 'one' row.