Essentially, in a relational data model, a unidirectional @OneToMany relationship is a type of relationship between two tables where one table has multiple related records in another table. Still, the second table doesn’t directly relate to the first table. This means that the relationship flows in only one direction.

Consider moving into the JPA, a unidirectional @OneToMany relationship can be established between two entities when one entity has a reference to the collection of related entities. Still, you cannot traverse back from the related entities to the first entity.

Generally, the entity containing the reference is called the parent entity, and the referenced entity is called the child entity.