What is the difference between criteria and DetachedCriteria?
Using a DetachedCriteria is exactly the same as a Criteria except you can do the initial creation and setup of your query without having access to the session.
What is criteria Distinct_root_entity?
setResultTransformer(Criteria. DISTINCT_ROOT_ENTITY); This statement is executed ex-post. Once the SQL query from DB engine is returned and Hibernate iterates the result set to convert that into list of our entities.
How do you put restrictions in criteria query?
Restrictions with Criteria Criteria cr = session. createCriteria(Employee. class); Criterion salary = Restrictions.gt(“salary”, 2000); Criterion name = Restrictions. ilike(“firstNname”,”zara%”); // To get records matching with OR conditions LogicalExpression orExp = Restrictions.or(salary, name); cr.
What is hibernate template in spring?
Spring’s HibernateTemplate provides an abstract layer over a Hibernate Session. It converts Hibernate-specific exceptions to one of the Spring’s unchecked data-access exception. It also provides many convenience methods that help you in querying and persisting objects.
How projection is used in hibernate criteria?
To put it simple, Hibernate Projections are used in order to query only a subset of the attributes of an entity or group of entities you’re querying with Criteria. You can also use Projections to specify distinct clauses and aggregate functions like max , sum and so on.
How do I select distinct rows in HQL?
You can use *SELECT DISTINCT(TO_CITY) FROM FLIGHT_ROUTE*. If you use SQL query, it return String List. You can’t use it return value by Entity Class.
What do you mean by HCQL?
The Hibernate Criteria Query Language (HCQL) is used to fetch the records based on the specific criteria. The Criteria interface provides methods to apply criteria such as retreiving all the records of table whose salary is greater than 50000 etc.
What is HibernateDaoSupport in Spring?
public abstract class HibernateDaoSupport extends DaoSupport. Convenient super class for Hibernate-based data access objects. Requires a SessionFactory to be set, providing a HibernateTemplate based on it to subclasses through the getHibernateTemplate() method.
What is Cascade in Hibernate?
Hibernate – Cascade example (save, update, delete and delete-orphan) Cascade is a convenient feature to save the lines of code needed to manage the state of the other side manually. The “Cascade” keyword is often appear on the collection mapping to manage the state of the collection automatically.
What is projection criteria?
Projections are generally used in the context of some Criteria. To put it simple, Hibernate Projections are used in order to query only a subset of the attributes of an entity or group of entities you’re querying with Criteria.
What is DTO projection?
You define a DTO projection in a CriteriaQuery in a pretty similar way as you do in JPQL. But instead of using the new keyword to specify the constructor call in a query String, you call the construct method on the CriteriaBuilder with a reference to the DTO class and a List of constructor parameters.