Hibernate-4

6.Query languages

Q-A)Why we need a query language in hibernate.

• for join quires.
• for update PK.

• JPQL queries can use in HQL,But HQL queries cant use JPQL.
• SQL queries cant use in JPQL & JPQL  queries cant use in SQL.

1. SQL include all DDL,DML quires.
2. But JPQL & HQL include DML quires.
3. JPQL include UPDATE,DELETE,SELECT quires.
4. HQL include UPDATE,DELETE,SELECT,INSERT INTO... SELECT quires. 

NH Vs JPAH differences in session vs entity manager

                Should be considered:-(R):return type

                                                   :-(Q):query language

1.Get data

CreateQuery vs CreateQuery

(R)Query/TypeQuery vs Query/TypeQuery

(Q)JPQL/HQL vs JPQL(Cant use for the SQL)

2.List of data

list() vs getResultList()

3.UniqueResult(0 vs getSingleResult()

4.addEntity vs <not define>

5.getNameQuery  vs createNamedQuery

6.getNamedNativeQuery Vs CreateNameQuery

Parameters

Using mixture of these parameters is no not a good practice

a)Positional Parameters

use number as parameter

use "?" to represent

Must be positive integer

Gap between 2 parameters should be always 1

Do not want to start 1 (can start like 50,51,52)

b)Named Parameters

use text for represent  parameters.

use ":" to represent