Hibernate. Return incomplete Object. Mapping issue

Question

maybe the title is not very self-explanatory but I going to describe the scenario as best as I can. I have a class called Hotel, and I want to return an object I take from the database, but there is one field that is not in the database and I don't know how to handle this cause I got an error. I show you, this is the Hotel class:

@Entity(name="Hotels")
public class Hotel {
    @Id @GeneratedValue
    private int id;
    @Column(name="name")
    private String name;
    @Column(name="category")
    private int category;
    @Column(name="base_price")
    private int base_price;
    @Column(name="region_id")
    private int region_id;
    @Column(name="adress")
    private String address;
    @Column(name="phone")
    private int phone;
    @Column(name="description")
    private String description;
    private Rate rate;

//SETTERS and GETTERS

public int getId() {
    return id;
}
public void setId(int id){
    this.id=id;
}
public String getName() {
    return name;
}

public void setName(String nombre) {
    this.name = nombre;
}
public int getBase_price() {
    return base_price;
}
public void setBase_price(int base_price) {
    this.base_price = base_price;
}
public int getRegion_id() {
    return region_id;
}
public void setRegion_id(int region_id) {
    this.region_id = region_id;
}
public int getCategory() {
    return category;
}
public void setCategory(int category) {
    this.category = category;
}
public String getDescription() {
    return description;
}
public void setDescription(String description) {
    this.description = description;
}
public int getPhone() {
    return phone;
}
public void setPhone(int phone) {
    this.phone = phone;
}
public String getAddress() {
    return address;
}
public void setAddress(String address) {
    this.address = address;
}
public Rate getRate() {
    return rate;
}
public void setRate(Rate rate) {
    this.rate = rate;
}

}

This is my database structure:

mysql> describe Hotels;
+-------------+--------------+------+-----+---------+----------------+
| Field       | Type         | Null | Key | Default | Extra          |
+-------------+--------------+------+-----+---------+----------------+
| id          | int(11)      | NO   | PRI | NULL    | auto_increment |
| name        | varchar(255) | NO   |     | NULL    |                |
| category    | int(11)      | NO   |     | NULL    |                |
| base_price  | int(11)      | NO   |     | NULL    |                |
| region_id   | int(11)      | NO   |     | NULL    |                |
| adress      | varchar(255) | NO   |     | NULL    |                |
| phone       | int(11)      | NO   |     | NULL    |                |
| photo_id    | int(11)      | NO   |     | NULL    |                |
| description | varchar(255) | NO   |     | NULL    |                |
+-------------+--------------+------+-----+---------+----------------+

And I want to return an Hotel object with these fields taken from the database: name,phone,address,base_price,category,description and region_id. I don't care about Rate, I want to return it with Rate=null. This is my function, where I have the problem:

public Hotel buscaHotel(int id) {

        Hotel nuevoHotel = new Hotel();

        SessionFactory sf = open();
        Session ss = sf.openSession();
        ss.beginTransaction();
        Query query = ss.createQuery("select u from Hotels u where id = :id ");
        query.setParameter("id", id);
        List<Hotel> list = query.list();
        if (list.size() != 0) {

            nuevoHotel = list.get(0);
            ss.getTransaction().commit();
            ss.close();
            return nuevoHotel;
        } else {
            ss.getTransaction().commit();
            ss.close();
            return nuevoHotel;

        }

    }

The error I got is this one:

org.hibernate.MappingException: Could not determine type for: manager.Rate, at table: Hotels, for columns: [org.hibernate.mapping.Column(rate)]

Just in case, on my hibernate.cfg.xml I have:

<mapping class="manager.Hotel"></mapping>

Answer 1

Field Rate rate is unmapped for Hibernate, so it doesn't know how to handle it when serializing/deserializing the data from the database.

Add the relevant association (@ManyToOne maybe) in your class and in your hibernate.cfg.xml file for Rate class.

In case you don't have the current mapping for Rate class ready, mark is with @Transient so Hibernate will ignore it.

@Transient
private Rate rate;