replace into 、INSERT IGNORE INTO

CREATE TABLE `file_monitors` (
   id int NOT NULL AUTO_INCREMENT,  # id 或 `id` 均可;
  `file_name` varchar(255) COLLATE utf8mb4_bin NOT NULL COMMENT '被处理的文件名称',
  `process_lines` int DEFAULT NULL COMMENT '本文中有多少条数据被处理',
  `process_time` timestamp NULL DEFAULT CURRENT_TIMESTAMP COMMENT '处理时间',
  PRIMARY KEY (`id`),
  UNIQUE KEY `file_name` (`file_name`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;



-- DROP TABLE file_monitors;

use metadata;
INSERT INTO file_monitors(file_name,process_lines)VALUES("x08",20);
INSERT IGNORE INTO file_monitors(file_name,process_lines)VALUES("x08",20); #  Affected rows: 0 尽管重复插入也不报错

replace into file_monitors(file_name,process_lines)VALUES("x08",20);

select * from file_monitors;


SHOW CREATE TABLE file_monitors;