Hi,
I am new to hibernate, I am trying to learn it and I have run into a problem trying to make one to many relationship's work. I have tried several examples but none seem to be working.
Can someone have a look at the below code and tell me where I have gone wrong. I have tried many different tutorials but it always doesn't work, so I must be missing something.
There are two classes: MovieDb and Genre. For each movie there will be many Genre's.
@Column(name = "movieId", insertable = true, updatable = true)If I set this line to false, there are no error messages but movieId on moviesGenre table is blank, everything else inserts correctly.
If I set this line to true, I get the following error:
Repeated column in mapping for entity: com.medialibrary.api.model.Genre column: movieId (should be mapped with insert="false" update="false")I believe I have included all the files and information needed, if not let me know.
Thanks for the help.
MovieDb.javaCode:
@Entity
@Table(name = "movies")
public class MovieDb extends IdElement {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;
@JsonProperty("id")
@Column(name = "movieId")
private int movieId;
@JsonProperty("title")
@Column(name = "title")
private String title;
@JsonProperty("genres")
@OneToMany(mappedBy="movie", cascade = CascadeType.ALL)
private List<Genre> genres;
public int getMovieId() { return movieId; }
public String getTitle() { return title; }
public List<Genre> getGenres() { return genres; }
public void setMovieId(int movieId) { this.movieId = movieId; }
public void setTitle(String title) { this.title = title; }
public void setGenres(List<Genre> genres) { this.genres = genres; }
}
Genre.javaCode:
@JsonRootName("genre")
@Entity
@Table(name = "moviesGenre")
public class Genre implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name="id")
private int id;
@Column(name = "movieId", insertable = true, updatable = true)
private int movieId;
@JsonProperty("name")
@Column(name = "name")
private String name;
@ManyToOne
@JoinColumn(name="movieId")
private MovieDb movie;
public int getMovieId() { return movieId; }
public String getName() { return name; }
public MovieDb getMovie() { return movie; }
public void setMovieId(int movieId) { this.movieId = movieId; }
public void setName(String name) { this.name = name; }
public void setMovie(MovieDb movie) { this.movie = movie; }
}
Main.javaCode:
public MovieDb getMovie(int movieId) {
Session s = HibernateUtil.getSessionFactory().openSession();
Transaction tx = s.beginTransaction();
MovieDb movie = null;
try {
String hql = "FROM MovieDb E WHERE E.movieId = " + movieId;
Query query = s.createQuery(hql);
List movies = query.list();
movie = (MovieDb)movies.get(0);
tx.commit();
}catch (HibernateException ex) {
if (tx != null)
tx.rollback();
}finally {
s.close();
}
return movie;
}
public void saveMovie(MovieDb movie) {
Session s = HibernateUtil.getSessionFactory().openSession();
Transaction tx = s.beginTransaction();
try {
s.save(movie);
s.flush();
tx.commit();
} catch (HibernateException ex) {
if (tx != null)
tx.rollback();
} finally {
s.close();
}
}
My database is setup like this:
moviesCode:
id int (primary)
movieId int
title varchar
moviesGenreCode:
id int (primary)
movieId int
name varchar
My Hibernate.cfg.xml file showing mapping is below:
Hibernate.cfg.xmlCode:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
...
...
...
<mapping class="com.medialibrary.api.model.MovieDb"/>
<mapping class="com.medialibrary.api.model.Genre"/>
</session-factory>
</hibernate-configuration>
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