Oracle data recovery methods: 1. Rollback operation: recent deleted changes can be undone; 2. Flashback query: view and access data at a certain point in the past; 3. Data pump export/import: recoverable Accidentally deleted data a long time ago; 4. Restoring backup: Recover data by restoring backup.
How to recover accidentally deleted data in Oracle
Accidental deletion of data is one of the common problems for database administrators . Oracle provides several mechanisms to recover deleted data.
1. Rollback operation
- If you have recently deleted data, you can try the rollback operation.
- Rollback will undo all changes made since the last commit, including data deletions.
- To roll back, use the following command:
ROLLBACK;
2. Flashback Query
- Flashback query allows you to view and Access data from a point in time in the past.
- To use Flashback queries, you need to enable the Flashback feature, which is disabled by default.
Enable Flashback:
ALTER DATABASE FLASHBACK ON;
Execute Flashback query:
SELECT * FROM table_name AS OF TIMESTAMP TO_TIMESTAMP('2023-03-08 10:00:00');
3. Data Pump Export/Import
- If the data has been accidentally deleted for a period of time, you can use Data Pump export/import to recover the data.
- First, export the data:
expdp user/password directory=DIR dumpfile=dumpfile.dmp
- Then, import the export file:
impdp user/password directory=DIR dumpfile=dumpfile.dmp
4. Restore the backup
- Regular backup of the database is the best method for data recovery.
- If you accidentally delete a previous backup, you can restore the backup to recover the data.
- The process of restoring a backup depends on the backup type.
Notes
- Restoring data may affect database performance.
- Before performing any recovery operations on a production database, testing is highly recommended.
- Back up the database regularly to avoid data loss.
The above is the detailed content of How to recover accidentally deleted data in oracle. For more information, please follow other related articles on the PHP Chinese website!

oracle asm指的是“自动存储管理”,是一种卷管理器,可自动管理磁盘组并提供有效的数据冗余功能;它是做为单独的Oracle实例实施和部署。asm的优势:1、配置简单、可最大化推动数据库合并的存储资源利用;2、支持BIGFILE文件等。

方法:1、利用“select*from user_indexes where table_name=表名”语句查询表中索引;2、利用“select*from all_indexes where table_name=表名”语句查询所有索引。

在Oracle中,可利用lsnrctl命令查询端口号,该命令是Oracle的监听命令;在启动、关闭或重启oracle监听器之前可使用该命令检查oracle监听器的状态,语法为“lsnrctl status”,结果PORT后的内容就是端口号。

在oracle中,可以利用“TO_SINGLE_BYTE(String)”将全角转换为半角;“TO_SINGLE_BYTE”函数可以将参数中所有多字节字符都替换为等价的单字节字符,只有当数据库字符集同时包含多字节和单字节字符的时候有效。

在oracle中,可以利用“drop sequence sequence名”来删除sequence;sequence是自动增加数字序列的意思,也就是序列号,序列号自动增加不能重置,因此需要利用drop sequence语句来删除序列。

在oracle中,可以利用“select ... From all_tab_columns where table_name=upper('表名') AND owner=upper('数据库登录用户名');”语句查询数据库表的数据类型。

方法:1、利用“LOWER(字段值)”将字段转为小写,或者利用“UPPER(字段值)”将字段转为大写;2、利用“REGEXP_LIKE(字符串,正则表达式,'i')”,当参数设置为“i”时,说明进行匹配不区分大小写。

方法:1、利用“alter system set sessions=修改后的数值 scope=spfile”语句修改session参数;2、修改参数之后利用“shutdown immediate – startup”语句重启服务器即可生效。


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

SublimeText3 Chinese version
Chinese version, very easy to use

SublimeText3 Mac version
God-level code editing software (SublimeText3)

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver CS6
Visual web development tools

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software
