JPA one-to-many entity relationships can be bidirectional (one entity contains a many-to-one relationship and the corresponding entity contains an inverse one-to-many relationship).
With SQL, one-to-many relationships are defined by foreign keys in one of the tables. The many part of the relationship is the one containing a foreign key to the one part of the relationship. One-to-many relationships defined in an RDBMS are typically unidirectional, since making them bidirectional usually results in denormalized data.
Just like when defining a unidirectional one-to-many relationship in an RDBMS, in JPA the many part of the relationship is the one that has a reference to the one part of the relationship, therefore the ...
