MyBatis Plus Mapper CRUD接口测试

插入

        插入一条记录

int insert(T entity);

删除 

        根据主键ID删除，主键ID支持String、Number类型

int deleteById(Serializable id);

        根据主键ID批量删除

int deleteBatchIds(Collection<? extends Serializable> idList);

        根据条件进行删除。原理为SQL语句拼接，因此Map中需要传输数据库字段列  
        实质为 delete from 表 where 【key1 = value1】 AND 【key2 = value2】
      【key1-value1】【key2-value2】为Map的键值对

int deleteByMap(Map<String, Object> columnMap);

更新

        根据ID更新。null值忽略。

        Employee employee = new Employee();
        employee.setId(7);
        employee.setLastName("a");
        employee.setAge(23);
        employee.setEmail(null);
        employee.setGender(null);
        mapper.updateById(employee);

 UPDATE tb_employee SET last_name='a', age=23
 WHERE id=7;

        根据条件更新，null值忽略。

        Employee employee = new Employee();
        employee.setId(7L);
        employee.setLastName("c");
        //这里设置的null，就是说不操作email字段
        employee.setEmail(null);
        employee.setGender(null);
        employee.setAge(23);
        mapper.update(employee, new UpdateWrapper<Employee>().lambda()
                .eq(Employee::getId, 7)
        );

 UPDATE tb_employee SET last_name='c', age=23
 WHERE (id = 7);

        定制置空。

        Employee employee = new Employee();
        employee.setId(7L);
        employee.setLastName("c");
        //这里设置的null，就是说不操作email字段
        employee.setEmail(null);
        employee.setGender(null);
        employee.setAge(23);
        mapper.update(employee, new UpdateWrapper<Employee>().lambda()
                .eq(Employee::getId, 7)
                //这里可以定制置空SQL
                .set(Employee::getEmail,null)
                .set(Employee::getGender,"")
        );

 UPDATE tb_employee SET last_name='c', age=23, email=null,gender=''
 WHERE (id = 7);