本部份內容,代碼戳這裏java
insert into `employee` (`id`, `age`, `name`) values('1','13','zhangsan'); insert into `employee` (`id`, `age`, `name`) values('2','20','test1'); insert into `employee` (`id`, `age`, `name`) values('3','21','test2'); insert into `employee` (`id`, `age`, `name`) values('4','22','test3'); insert into `employee` (`id`, `age`, `name`) values('5','20','test4'); insert into `employee` (`id`, `age`, `name`) values('6','21','test5'); insert into `employee` (`id`, `age`, `name`) values('7','22','test6'); insert into `employee` (`id`, `age`, `name`) values('8','22','test16');
更新和刪除操做用到了一個新的註解@Modifying
spring
通常狀況下,咱們須要使用@Modifying
和@Query
註解執行更新和刪除sql
若是隻使用@Query
註解,如:數據庫
@Query("update Employee o set o.age = ?2 where o.id = ?1") public void update(Integer id, Integer age);
會拋出下面異常ui
org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [update com.dotleo.entity.Employee o set o.age = ?2 where o.id = ?1]; nested exception is java.lang.IllegalStateException: org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [update com.dotleo.entity.Employee o set o.age = ?2 where o.id = ?1] ... Caused by: java.lang.IllegalStateException: org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [update com.dotleo.entity.Employee o set o.age = ?2 where o.id = ?1] ... 37 more Caused by: org.hibernate.hql.internal.QueryExecutionRequestException: Not supported for DML operations [update com.dotleo.entity.Employee o set o.age = ?2 where o.id = ?1] ... 57 more
咱們爲它加上@Modifying
註解,如:hibernate
@Modifying @Query("update Employee o set o.age = ?2 where o.id = ?1") public void update(Integer id, Integer age);
運行後會發現,仍是報錯code
org.springframework.dao.InvalidDataAccessApiUsageException: Executing an update/delete query; nested exception is javax.persistence.TransactionRequiredException: Executing an update/delete query ... Caused by: javax.persistence.TransactionRequiredException: Executing an update/delete query ...
這又是爲何呢?事務
其實,若是是查詢操做,咱們沒有必要事務。可是更新操做,咱們要求數據的完整性,因此必須爲操做添加事務。開發
有Java EE開發經驗的人確定知道,若是一次須要操做多張表(執行多個DAO),業務邏輯會寫在Service裏,這樣一個Service方法中調用的全部DAO層方法都被集合到一個事務中,保證了數據的完整性。get
所以,須要先創建EmployeeService
,而後再調用EmployeeRepository
中的方法。
注意,在Service的方法中,咱們必須爲之添加@Transactional
註解,讓它支持事務,才能運行成功。
package com.dotleo.service; import com.dotleo.repository.EmployeeRepository; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; /** * @author LiuFei * @create 2017-11-10 22:57 */ @Service public class EmployeeService { @Autowired private EmployeeRepository employeeRepository; @Transactional public void update(Integer id, Integer age) { employeeRepository.update(id, age); } }
刪除操做不過是sql語句的變化,其餘更爲複雜的更新操做也不過是sql語句的變化,請加練習有助於記憶。
最終源代碼:戳這裏