更新現有的列值

Question

我有一個實體的用戶，併爲用戶我的DB值：

name  totalScore 
-------------------- 
ABC  25 
XYZ  30 

現在我想運行查詢

update user set totalScore=totalScore+ (2*totalScore); 

我們怎樣才能achive它通過JPA 2.1 CriteriaUpdate？

CriteriaBuilder criteriaBuilder = em().getCriteriaBuilder(); 
     //Updates the salary to 90,000 of all Employee's making more than 100,000. 
     CriteriaUpdate update = criteriaBuilder.createCriteriaUpdate(User.class); 
     Root user = update.from(User.class); 
     Expression<Long> abc=user.get("totalScore"); 

     update.set("totalScore", ??); 
// what expression is here to be used to replace old value with new 
     Query query = em().createQuery(update); 
     int rowCount = query.executeUpdate(); 

Answer 1

您可以使用此代碼。它會爲你

// Gives all Employees a 10% raise. 

CriteriaUpdate update = criteriaBuilder.createCriteriaUpdate(Employee.class); 

Root employee = update.from(Employee.class); 

update.set(employee.get("salary"),criteriaBuilder.sum(employee.get("salary"), criteriaBuilder.quot(employee.get("salary"), 10)); 

Query query = entityManager.createQuery(update); 
int rowCount = query.executeUpdate(); 

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