这里说明因为Update 操作的恢复方法:主要还是通过binlog来进行恢复,前提是binlog_format必须是Row格式,否则只能通过备份来恢复数据了。和上一篇的条件一样。 方法: 条件:开启Binlog,Format为Row。 步骤: 1.通过MySQL自带工具mysqlbinlog 指定导出操作的记录: 表结构和记录数: root@localhost : test10:06:16>select...
/bin/env python # -*- encoding: utf-8 -*- #--- # Name: restore_update.py # Purpose: 通过Binlog恢复Update误操作数据 # Author: zhoujy # Created: 2012-12-26 # update: 2012-12-26 # Copyright: (c) Mablevi 2012 # Licence: zjy # Usage: python restore_update.py binlog.txt tablen...
接收一条Query后,会进行SQL解析,生成语法树,接下来会生成执行计划,选择最优的执行计划进行执行,对于一条SQL,可能有多种执行计划,观察和分析执行计划可以帮助开发人员以及DBA优化SQL. With the help of EXPLAIN, you can see where you should add indexes to tables so that the statement executes faster by usin...
UPDATE student_score SET student_id = 2 WHERE student_id = 1; ERROR 1452 (23000) : Cannot ADD OR UPDATE a child ROW : a FOREIGN KEY CONSTRAINT fails ( `tts`.`student_score`, CONSTRAINT `s_id` FOREIGN KEY (`student_id`) REFERENCES `student` (`id`) ) (3)主表删除行,其主键值在...
for EACH row -- 固定写法 BEGIN update goods set num = num -new.much where id =new.gid; END -- 删除触发器--- drop TRIGGER TG1; 2.更新事件触发器--- update order_table set much = much +2 where oid = 6; update goods set num = num+2 where id = 1; ...
这里如果在stu_scores表中插入insert into stu_scores values(null,'S_1001',88);是可以插入成功的,因为在stu表中是有sid为S_1001的元素;但如果插入insert into stu_scores values(null,'S_1012',99);就会报错,ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (...
create trigger 触发器名 before|after insert|update|deleteon 表名foreach row begin 执行语句 end$$--定义结束符号 delimiter; 触发事件类型 insert:有数据新增时触发 update:有数据被修改时触发 delete:有数据被删除时触发 执行顺序 before:在触发事件前执行语句 ...
更新数据：UPDATE 表名称 SET 列名1=新数据1，列名2=新数据2 WHERE 某列=某数据；4、连接数据库 安...
INSERTINTOtbl_nameVALUES/SET/SELECTONDUPLICATEKEYUPDATE字段=值, …; DELETE DELETEFROMtbl_name [WHEREwhere_definition] [ORDERBY...] [LIMITrow_count] 按照条件删除。where 指定删除的最多记录数。limit 可以通过排序条件删除。orderby+limit 支持多表删除,使用类似连接语法。
row_count (int)– The maximum number of items. Returns: FilterableStatement object. Return type: mysqlx.FilterableStatement Raises: ValueError –If row_count is not a positive integer. Changed in version 8.0.12: The usage of offset was deprecated.offset...