Question

Im moving to java from C#, this is my frist try at actually writting something and I’m trying to setup my data layer, but I think I’m missing something like DataContext in LINQ to SQL in .NET

Im trying to query database using Hibernate but it seems like I’m missing something, I downloaded Hibernate 4 and QueryDSL for type safe queries.

Next I connected to my postgreSQL database and generated DAO objects using Dali(I think? in menu I selected JPA enteties from tables), written queries that I need but I am unsure which object I have to execute my query on (something like connection manager or something?)

Im missing something here I think:

EmployeesRepository repo = new EmployeesRepository();
List<Employees> employees = repo.GetByName("Steve");
Employees s = employees.get(0);
String g = s.getName();

My entity repository:

public class EmployeesRepository {

    public List<Employees> GetByName(String ename)
    {
        HibernateQuery qry = createQuery(employees);
        qry.where(employees.name.like(ename));
        return qry.list(employees);
    }

    private HibernateQuery createQuery(QEmployees employee)
    {
        return new HibernateQuery().from(employee);
    }
}

Im getting:

java.lang.UnsupportedOperationException: No session in detached Query available

Answer 1

You need to create/open a hibernate session before executing query.

Example:

Session session = HibernateUtil.getSessionFactory().openSession();

When you are done with query execution, you need to close.

session.close();

Here is step by step example.

Note: There may be a hibernate version mismatch between what you are using and the one described in above example, you may need to just tweek it.