Hibernate Named Query Introduction Tutorial

Posted by: Instanceofjava Posted date: 6:14 PM / comment : 0 hibernate interview questions , Hibernate named query , Hibernate Tutorial

• If we are using HQL or Native SQL queries multiple time then it will be code mess because all queries will be scattered throughout the project.
• Hibernate Named Query is a way to use queries by giving a name.
• Hibernate Named Queries will be defined at one place and used anywhere in the project.
• use of named query in hibernate
• Writing HQL query in HBM file is called HQL Named Query.
• Or we can use @NameQuery annotation in entity.
• For writing Hibernate Named Queries we will use <query> tag in Hibernate mapping file Or @NameQuery annotation in the entity.
• If we want to create Named Query using hibernate mapping file then we need to use query element.

Advantages of Named Query in Hibernate 

• Global access
• Easy to maintain.

Hibernate Named Queries by using Annotations:

• If we want to create Named Queries using annotations in entity class then we need to use @NameQueries and @NameQuery annotations
• @NameQuery will be used to create single Query
• @NameQueries annotations will be used to create multiple Queries. When we are using @NameQueries for every query we need to use @NameQuery annotation.

Hibernate Named Query example by using Annotations:

1. Query query = session.getNamedQuery("findDocterById");
2.         query.setInteger("id", 37);
3.        List empList = query.list();

Hibernate Named Queries by using Hibernate mapping file:

• We need to configure Hibernate Named Queries as part of Hibernate mapping file.
• By using <query> element we need to write Hibernate named Queries.

1. <hibernate_mapping>
2.             <class  >
3.             ---------
4.             </class>
5.  
6.  <query name = “findDocterById”>
7.  <![CDATA[from Docter s where s.id = :id]]>
8. </query>  
9. 
   
10.  </hibernate_mapping>     

1. Query query = session.getNamedQuery("findDocterById");
2.         query.setInteger("id", 64);
3.        List empList = query.list();