What are some examples of Hibernate queries?

Can you provide some examples of Hibernate queries?

Sure! Here are a few examples of Hibernate queries:

1. HQL: FROM Employee WHERE salary > 50000
2. Criteria API: session.createCriteria(Employee.class).add(Restrictions.gt("salary", 50000)).list();
3. Native SQL: SELECT * FROM employees WHERE salary > 50000; Would you like to see more details on any of these?

Yes, can you explain the Criteria API example?

Of course! The Criteria API allows you to create queries programmatically. In the example, session.createCriteria(Employee.class) creates a criteria query for the Employee entity. The add(Restrictions.gt("salary", 50000)) part adds a restriction to filter employees with a salary greater than 50,000. Finally, .list() executes the query and returns the results.

What are the advantages of using HQL over SQL?

HQL is object-oriented and works with entity objects rather than database tables, making it more flexible and easier to maintain. It also supports polymorphic queries and is database-independent, which means you can switch databases without changing your queries.

Can you show me a complex HQL query?

Certainly! Here's a complex HQL query: SELECT e FROM Employee e JOIN e.department d WHERE d.name = 'Sales' AND e.salary > 60000 ORDER BY e.salary DESC. This query retrieves employees from the Sales department with a salary greater than 60,000, ordered by salary in descending order.