如何使用条件在休眠模式下编写“ where”查询

Question

Let me consider one simple sql query

select username from tbl_customer where username="user" and password="12345";

How can i write this query in hibernate using criteria

Thanks. Hoping for positive response..

Answer 1

first you have to create the Criteria object, then you need to pass the where clause condition to the criteria object as well you have to set the projection property for selecting particular column data.

By seeing your SQL query,

select username from tbl_customer where username="user" and password="12345";

I believe you want to fetch the particular column username from the table tbl_customer . This can be done using Projections . You have to set the projection property for which column data you want.

Criteria criteria = session.createCriteria(MyClass.class)
  criteria.setProjection(Projections.property("username"));
  criteria.add(Restrictions.and(Restrictions.eq("username", user),Restrictions.eq("password", 12345))
);
List<String> userNames = criteria.list();

This will return only the username column data from that table.

Answer 2

Criteria criteria = session.createCriteria(Customer.class) 
.add(Restrictions.eq("username", 
"user").add(Restrictions.eq("password","12345")); 

Please note that, I do consider entity name as Customer for tbl_customer and you created session correctly.