org.hibernate.query.criteria.internal.BasicPathUsageException
The org.hibernate.query.criteria.internal.BasicPathUsageException is an exception that occurs when trying to perform a join operation on an attribute of basic type in Hibernate.
In Hibernate, there are two types of attributes: basic attributes and association attributes. Basic attributes refer to simple data types such as strings, numbers, or dates. Association attributes refer to other entities or collections.
When using Hibernate Criteria API to perform a join operation, it is important to use association attributes for joining tables instead of basic attributes. If you try to join a table using a basic attribute, the BasicPathUsageException will be thrown.
Example:
Let’s consider a simple example where we have two entities: Order and Customer. The Order entity has a basic attribute called customerId, which stores the ID of the customer who placed the order.
@Entity
public class Order {
@Id
private Long id;
private Long customerId;
// Other attributes and relationships
}
@Entity
public class Customer {
@Id
private Long id;
// Other attributes and relationships
}
If we want to perform a join operation between the Order and Customer entities using their IDs, we should define an association attribute between them, such as a ManyToOne relationship:
@Entity
public class Order {
@Id
private Long id;
@ManyToOne
@JoinColumn(name = "customer_id")
private Customer customer;
// Other attributes and relationships
}
@Entity
public class Customer {
@Id
private Long id;
// Other attributes and relationships
}
Now, we can use the association attribute customer to perform the join operation:
CriteriaBuilder criteriaBuilder = session.getCriteriaBuilder();
CriteriaQuery<Order> criteriaQuery = criteriaBuilder.createQuery(Order.class);
Root<Order> orderRoot = criteriaQuery.from(Order.class);
Join<Order, Customer> customerJoin = orderRoot.join("customer", JoinType.INNER);
criteriaQuery.select(orderRoot);
criteriaQuery.where(criteriaBuilder.equal(customerJoin.get("id"), 1L));
List<Order> orders = session.createQuery(criteriaQuery).getResultList();
In this example, we create a join between the Order and Customer entities using customer association attribute. We then filter the orders based on the customer ID.
By using the correct association attribute, we prevent the occurrence of the BasicPathUsageException when performing the join operation in Hibernate.