Question

Recently i am started using hibernate. to insert or update i am using saveOrUpdate() function.
If i update an entry i works fine. But, with new entry hibernate generate a Query. Buts nothing gets updated in the table.

My scenario is like this,

i am using Many to One & One to Many relationship between two tables[Expense, Category]
For update or insert, i am creating two objects(Expense expense, Category category) from the
client side. In the server side, i set category object with expense object.

public void upDateExpenseTable(Expens expense, Category category) {

    expense.setCategory(category);
    Session session = Main.getSession();
    try{
        System.out.println("Inside Update Try Block");
        session = Main.getSession();
        Transaction tr = session.beginTransaction();
        session.saveOrUpdate(expense);
        tr.commit();

    }
    finally{
        session.close();
    }
}

Object structure is like, catogery.catId, category.catName &
expense.expnsId, expense.expnsName, expense.amount, expense.status, expense.userName.

But there is another one column in Expense Table cat_id. Its is through mapping annotation. But i dont have any property for that in Expense entity.
When inserting new data, i am not giving any Id.

Any suggestions!!!

public class Expens implements Serializable {
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private int expnsId;
private int amount;
private String date;
private String status;
private String userName;

    @ManyToOne
@JoinColumn(name = "cat_id") 
private Category category;
    //Setter Getter

}

Category Classs

public class Category{
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private int catId;
private String catName;

@OneToMany(targetEntity=Expens.class, mappedBy = "category", cascade = CascadeType.ALL, fetch=FetchType.EAGER)
private List<Expens> expenses;
}//Setters Getters ommited.

Answer 1

I’m not sure I understood everything but I can at least tell you that you’re not building your bi-directional association correctly, you need to set “both sides of the link” when building your object graph:

...
expense.setCategory(category);
category.getExpenses().add(expense);
...
session.saveOrUpdate(category);

And this is usually done in “link management” methods, like this (in Category):

@Entity
public class Category {

    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    private int catId;
    private String catName;

    @OneToMany(targetEntity=Expens.class, mappedBy = "category", cascade = CascadeType.ALL, fetch=FetchType.EAGER)
    private List<Expens> expenses = new ArrayList<Expens>();

    public void addToExpenses(Expense expense) {
        expenses.add(expense);
        expense.setCategory(this);
    }    

    protected List getExpenses() { // protected to prevent direct access from outside the hierarchy
        return expenses;
    }

    protected void setExpenses(List expenses) { // protected to prevent direct access
        this.expenses = expenses;
    }

    //...
}

And the code becomes:

category.addToExpenses(expense);
session.saveOrUpdate(category);

Funnily enough (or not), I’ve written about this three times today.

Resource

• Hibernate Core Documentation
  • 1.2.6. Working bi-directional links