tk.mybatis之批量更新修改数据，foreach和case when then实现笔记

目录

批量更新描述

foreach写法：

case when then写法：  when后面的条件必须能确定一条数据，即id

case when then 的mapper接口方式实现动态sql批量插入

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批量更新描述

tk.mybatis没有带批量更新的功能，批量更新却是经常使用

实现批量更新主要有两种方式：

case when then方式：一条sql实现多条数据多个字段数据更新。

foreach方式：生成多条数据更新数据库。

 

foreach写法：

这种方式效率非常低下，比较普通的写法，是通过循环，依次执行update语句。

xml配置写法如下：

  
    
        update course
        
            name=${item.name}
        
        where id = ${item.id}
          

结果：一条记录update一次，性能比较差，容易造成阻塞。

 

 

case when then写法：  when后面的条件必须能确定一条数据，即id

表结构：

sql写法1 ：  case  后接主键

UPDATE stream_box SET
	capability  = CASE stream_box_id 
			WHEN 'sboxbatchInsertTKMybatis1' THEN 1001
			WHEN 'sboxbatchInsertTKMybatis2' THEN 1001
			WHEN 'sboxbatchInsertTKMybatis3' THEN 1001
			WHEN 'sboxbatchInsertTKMybatis4' THEN 1001
			WHEN 'sboxbatchInsertTKMybatis5' THEN 1001
	END,
	use_state  = CASE stream_box_id 
			WHEN 'sboxbatchInsertTKMybatis1' THEN 0
			WHEN 'sboxbatchInsertTKMybatis2' THEN 0
			WHEN 'sboxbatchInsertTKMybatis3' THEN 0
			WHEN 'sboxbatchInsertTKMybatis4' THEN 0
			WHEN 'sboxbatchInsertTKMybatis5' THEN 0
	END 
	 WHERE op_state=1;

 

sql写法2  ： when后面接主键

UPDATE stream_box SET
	capability  = CASE 
			WHEN stream_box_id ='sboxbatchInsertTKMybatis1' AND  stream_line_id ='slineid1'  THEN 3333
			WHEN stream_box_id ='sboxbatchInsertTKMybatis2' AND  stream_line_id ='slineid2'  THEN 3333
			WHEN stream_box_id ='sboxbatchInsertTKMybatis3' AND  stream_line_id ='slineid3'  THEN 3333
			WHEN stream_box_id ='sboxbatchInsertTKMybatis4' AND  stream_line_id ='slineid4'  THEN 3333
			WHEN stream_box_id ='sboxbatchInsertTKMybatis5' AND  stream_line_id ='slineid5'  THEN 3333
	END,
	use_state  = CASE  
			WHEN stream_box_id ='sboxbatchInsertTKMybatis1' AND  stream_line_id ='slineid1'   THEN 0
			WHEN stream_box_id ='sboxbatchInsertTKMybatis2' AND  stream_line_id ='slineid2'   THEN 0
			WHEN stream_box_id ='sboxbatchInsertTKMybatis3' AND  stream_line_id ='slineid3'   THEN 0
			WHEN stream_box_id ='sboxbatchInsertTKMybatis4' AND  stream_line_id ='slineid4'   THEN 0
			WHEN stream_box_id ='sboxbatchInsertTKMybatis5' AND  stream_line_id ='slineid5'   THEN 0
	END 
	 WHERE op_state=1;

 

 

dao层接口：

 int updateSboxByPrimaryKeySelective(@Param("list") List list);

xml配置文件写法：

 
    
         UPDATE stream_box
         
             
                
                    when stream_box_id = #{item.streamBoxId} then #{item.capability}
                
             
             
                 
                     when stream_box_id = #{item.streamBoxId} then #{item.useState}
                 
             
         
         where
         
             stream_box_id =#{item.streamBoxId}
         
    

 

测试代码

  @Test
    public void caseWhenThenTest(){
        List sBoxes = getSboxes("batchInsertTKMybatis");
        sBoxes.forEach(sBox -> {
            sBox.setUseState((byte)0);
            sBox.setCapability(10000d);

        });
        int i = streamBoxDao.updateSboxByPrimaryKeySelective(sBoxes);
        System.out.println("成功更改：\t" + i +  "条数据");
    }

控制台日志：

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@386d41cb] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@5da41d02] will not be managed by Spring
==>  Preparing: UPDATE stream_box set capability = CASE when stream_box_id = ? then ? when stream_box_id = ? then ? when stream_box_id = ? then ? when stream_box_id = ? then ? when stream_box_id = ? then ? END, use_state = CASE when stream_box_id = ? then ? when stream_box_id = ? then ? when stream_box_id = ? then ? when stream_box_id = ? then ? when stream_box_id = ? then ? END where stream_box_id =? or stream_box_id =? or stream_box_id =? or stream_box_id =? or stream_box_id =? 
==> Parameters: sboxbatchInsertTKMybatis1(String), 10000.0(Double), sboxbatchInsertTKMybatis2(String), 10000.0(Double), sboxbatchInsertTKMybatis3(String), 10000.0(Double), sboxbatchInsertTKMybatis4(String), 10000.0(Double), sboxbatchInsertTKMybatis5(String), 10000.0(Double), sboxbatchInsertTKMybatis1(String), 0(Byte), sboxbatchInsertTKMybatis2(String), 0(Byte), sboxbatchInsertTKMybatis3(String), 0(Byte), sboxbatchInsertTKMybatis4(String), 0(Byte), sboxbatchInsertTKMybatis5(String), 0(Byte), sboxbatchInsertTKMybatis1(String), sboxbatchInsertTKMybatis2(String), sboxbatchInsertTKMybatis3(String), sboxbatchInsertTKMybatis4(String), sboxbatchInsertTKMybatis5(String)
<==    Updates: 5
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@386d41cb]
成功更改：	5条数据

 

以上参考：https://www.cnblogs.com/exmyth/p/5757137.html

 

 

case when then 的mapper接口方式实现动态sql批量插入

可参考：https://blog.csdn.net/sunct/article/details/90146681