MyBatis逆向工程生成dao层增删改查方法解释使用(转载)
作者:互联网
int countByExample(BUserExample example); //根据条件查询数量 /** * 示例 * public int countByExample() { * BUserExample userExample = new BUserExample(); * BUserExample.Criteria criteria = userExample.createCriteria(); * criteria.andUsernameEqualTo("fan"); * int count = userMapper.countByExample(userExample); * return count; * } * 相当于:select count(*) from user where username = 'fan' */ int deleteByExample(BUserExample example); //根据条件删除数据(一条或多条) /** * 示例 * public int deleteByExample() { * BUserExample userExample = new BUserExample(); * BUserExample.Criteria criteria = userExample.createCriteria(); * criteria.andUsernameEqualTo("fan"); * int count = userMapper.deleteByExample(userExample); * return count; * } * 相当于:delete from user where username = 'fan' */ int deleteByPrimaryKey(Integer id); //根据主键删除数据 int insert(BUser record); //插入数据(插入一条数据) int insertSelective(BUser record); //插入数据(插入一条数据,只插入不为null的字段,不会影响有默认值的字段) List<BUser> selectByExample(BUserExample example); //根据条件查询数据 /** * 示例: * public List<BUser> getList() { * BUserExample userExample = new BUserExample(); * BUserExample.Criteria criteria = userExample.createCriteria(); * criteria.andUsernameEqualTo("fan"); * userExample.setOrderByClause("username desc"); * List<BUser> users = userMapper.selectByExample(userExample); * return users; * } * 相当于:select * from user where username = 'fan' order by username desc */ BUser selectByPrimaryKey(Integer id); //根据主键查询 int updateByExampleSelective(@Param("record") BUser record, @Param("example") BUserExample example); //按条件更新值不为null的字段 /** * 示例: * public int updateByParam(String username) { * BUserExample userExample = new BUserExample(); * BUserExample.Criteria criteria = userExample.createCriteria(); * criteria.andUsernameEqualTo(username); * BUser user = new BUser(); * user.setNickname("jdk"); * int update = userMapper.updateByExampleSelective(user, userExample); * return update; * } * 相当于:update user set nickname = 'jdk' where username = #{username} */ int updateByExample(@Param("record") BUser record, @Param("example") BUserExample example); //按条件更新 int updateByPrimaryKeySelective(BUser record); //根据主键与条件更新 /** * 示例: * public int updateByIdAndParam(String username) { * BUser user = new BUser(); * user.setId(101); * user.setUsername(username); * int update = userMapper.updateByPrimaryKeySelective(user); * return update; * } * 相当于:update user set username = #{username} where id = 101 */ int updateByPrimaryKey(BUser record); //根据主键更新
原文链接:https://blog.csdn.net/feidao0/article/details/80731824
标签:username,BUser,int,dao,改查,BUserExample,user,MyBatis,userExample 来源: https://www.cnblogs.com/qfdy123/p/11565207.html