javahurdles

In database we have a foreign key.  In simple foreign key establish the relationship between two database tables. Primary key of one table is placed into another table.  That key is called  foreign key. Here can have a book table and author table . Every author is linked with those books which are written by him.  So inside the book there is author name. that reflect the relation.  In relationship database model. Author is identified by his unique identification, This is the primary key of author table.  Book table will contain the identification of author. Book table have author id and this foreign key is not unique in book table. One single author can write multiple books, @JoinColumn specifies the foreign key column is the Book table that links to the Author entity. In this case, it's author_id. A n example of how to use @JoinColumn annotation with @ManyToOne and @OneToMany relationships in JPA. Consider two entities Author and Book , where an author...