Add data to database adding data to join tables - jpa

Question

I'm working in a project and I'm looking to add data to the database, to two join tables.
My parent:
package entity;
import java.io.Serializable;
import javax.persistence.*;
/**
* The persistent class for the artiste database table.
*
*/
#Entity
#NamedQuery(name="Artiste.findAll", query="SELECT a FROM Artiste a")
public class Artiste implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name="id_artiste")
private int idArtiste;
#Column(name="a_category")
private String aCategory;
#Column(name="a_name")
private String aName;
private String date;
//bi-directional many-to-one association to Seat
#ManyToOne
#JoinColumn(name="id_seat")
private Seat seat;
public Artiste() {
}
public int getIdArtiste() {
return this.idArtiste;
}
public void setIdArtiste(int idArtiste) {
this.idArtiste = idArtiste;
}
public String getACategory() {
return this.aCategory;
}
public void setACategory(String aCategory) {
this.aCategory = aCategory;
}
public String getAName() {
return this.aName;
}
public void setAName(String aName) {
this.aName = aName;
}
public String getDate() {
return this.date;
}
public void setDate(String date) {
this.date = date;
}
public Seat getSeat() {
return this.seat;
}
public void setSeat(Seat seat) {
this.seat = seat;
}
}
My child:
package entity;
import java.io.Serializable;
import javax.persistence.*;
import java.util.List;
/**
* The persistent class for the seat database table.
*
*/
#Entity
#NamedQuery(name="Seat.findAll", query="SELECT s FROM Seat s")
public class Seat implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name="id_seat")
private int idSeat;
private String seat_CA;
private String seat_CB;
private String seat_CC;
private String seat_CD;
//bi-directional many-to-one association to Artiste
#OneToMany(mappedBy="seat")
private List<Artiste> artistes;
public Seat() {
}
public int getIdSeat() {
return this.idSeat;
}
public void setIdSeat(int idSeat) {
this.idSeat = idSeat;
}
public String getSeat_CA() {
return this.seat_CA;
}
public void setSeat_CA(String seat_CA) {
this.seat_CA = seat_CA;
}
public String getSeat_CB() {
return this.seat_CB;
}
public void setSeat_CB(String seat_CB) {
this.seat_CB = seat_CB;
}
public String getSeat_CC() {
return this.seat_CC;
}
public void setSeat_CC(String seat_CC) {
this.seat_CC = seat_CC;
}
public String getSeat_CD() {
return this.seat_CD;
}
public void setSeat_CD(String seat_CD) {
this.seat_CD = seat_CD;
}
public List<Artiste> getArtistes() {
return this.artistes;
}
public void setArtistes(List<Artiste> artistes) {
this.artistes = artistes;
}
public Artiste addArtiste(Artiste artiste) {
getArtistes().add(artiste);
artiste.setSeat(this);
return artiste;
}
public Artiste removeArtiste(Artiste artiste) {
getArtistes().remove(artiste);
artiste.setSeat(null);
return artiste;
}
}
My client:
Artiste a= new Artiste();
Seat b = new Seat();
b.setSeat_CA(request.getParameter("w"));
b.setSeat_CB(request.getParameter("x"));
b.setSeat_CD(request.getParameter("y"));
b.setSeat_CC(request.getParameter("z"));
a.setIdArtiste(b.getIdSeat());
seatFacade.create(b);
a.setAName(request.getParameter("a_name"));
a.setACategory(request.getParameter("a_category"));
a.setDate(request.getParameter("date"));
artisteFacade.create(a);
And I create the FACADE for each one.
Now I can add data but i need also the program add the FOREIGN KEY.

Answer 1

You don't need to get the foreign key, JPA is do every thing, so you should just make it in the right way, so you entities should look like this:
Artiste Entity
#ManyToOne
#JoinColumn(name="id_seat")
private Seat seat;
Seat Entity
#OneToMany(mappedBy="seat", cascade = CascadeType.ALL)
private List<Artiste> artistes = new ArrayList<>();
Your code should look like this:
Artiste a= new Artiste();
Seat b = new Seat();
b.setSeat_CA(request.getParameter("w"));
b.setSeat_CB(request.getParameter("x"));
b.setSeat_CD(request.getParameter("y"));
b.setSeat_CC(request.getParameter("z"));
a.setAName(request.getParameter("a_name"));
a.setACategory(request.getParameter("a_category"));
a.setDate(request.getParameter("date"));
//add this the Article to the list of Seat like this.
b.getArtistes().add(a);
//a.setIdArtiste(b.getIdSeat()); you don't need this
//artisteFacade.create(a); you dont need this also
//set the Seal to your article
a.setSeat(b);
seatFacade.create(b);
So when you persist the Seat the list of articles will persist automaticlly.
This will help you.
You can learn more here : JPA #ManyToOne with CascadeType.ALL