Introduction Someone asked me to answer the following StackOverflow question, and, because the question is very interesting from an SQL perspective, I decided to turn the answer it into a blog post. In this article, we are going to see how to map a JPA @ManyToOne association to the result of a SQL query using the Hibernate-specific @JoinFormula annotation.
Introduction While answering questions on the Hibernate forum, I stumbled on the following question about using the @ManyToOne annotation when the Foreign Key column on the client side references a non-Primary Key column on the parent side. In this article, you are going to see how to use the @JoinColumn annotation in order to accommodate non-Primary Key many-to-one associations.
Introduction In a relational database system, a one-to-many association between links two tables based on a Foreign Key column so that the child table record references the Primary Key of the parent table row. As straightforward as it might be in a RDBMS, when it comes to JPA, the one-to-many database association can be represented either through a @ManyToOne or a @OneToMany association since the OOP association can be either unidirectional or bidirectional. The @ManyToOne annotation allows you to map the Foreign Key column in the child entity mapping so that the… Read More