How can I mark a foreign key constraint using Hibernate annotations

Question

I am trying to use Hibernate annotation for writing a model class for my database tables   I have two tables  each having a primary key User and Question    Entity  Table name  USER   public class User        Id      Column name  user id        GeneratedValue strategy GenerationType AUTO      private Long id        Column name  username       private String username          Getter and setter     Question Table    Entity  Table name  QUESTION   public class Questions extends BaseEntity        Id      Column name  question id        GeneratedValue strategy GenerationType AUTO      private int id        Column name  question text       private String question text          Getter and setter     And I have one more table  UserAnswer  which has userId and questionId as foreign keys from the above two tables   But I am unable to find how I can reference these constraints in the UserAnswer table    Entity  Table name  UserAnswer    public class UserAnswer        Column name  user id       private User user          ManyToMany      Column name  question id       private Questions questions         Column name  response       private String response          Getter and setter     How can I achieve this

User · Answer

JoinColumn name  reference column name   annotation can be used above that property or field  of class that is being referenced from some other entity

User · Answer

There are many answers and all are correct as well  But unfortunately none of them have a clear explanation   The following works for a non-primary key mapping as well   Let s say we have parent table A with column 1 and another table  B  with column 2 which references column 1    ManyToOne  JoinColumn name    TableBColumn   referencedColumnName    TableAColumn   private TableA session UserName       ManyToOne  JoinColumn name    bok aut id   referencedColumnName    aut id   private Author bok aut id

User · Answer

Column is not the appropriate annotation  You don t want to store a whole User or Question in a column  You want to create an association between the entities  Start by renaming Questions to Question  since an instance represents a single question  and not several ones  Then create the association    Entity  Table name    UserAnswer   public class UserAnswer           this entity needs an ID       Id      Column name  useranswer id        GeneratedValue strategy   GenerationType AUTO      private Long id        ManyToOne      JoinColumn name    user id       private User user        ManyToOne      JoinColumn name    question id       private Question question        Column name    response       private String response         getter and setter      The Hibernate documentation explains that  Read it  And also read the javadoc of the annotations

[java] How can I mark a foreign key constraint using Hibernate annotations?

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