oracle 数据库闪回相关语句介绍
本文将详细介绍oracle 数据库闪回相关语句,需要了解跟多的朋友可以参考下
1\将表闪回到某一时间点:闪回操作前启用行移动功能
Sql代码
alter table emp enable row movement;
执行闪回语句:
Sql代码
flashback table emp to timestamp to_timestamp('20120709195000','YYYYMMDDHH24:MI:SS');
2\闪回回收站:
Java代码
SQL>show recyclebin;
SQL>drop table emp;
SQL>show recyclebin;
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
EMP BIN$b+XkkO1RS5K10uKo9BfmuA==$0 TABLE 2012-11-07:15:30:47
SQL>flashback table emp to before drop;或
SQL>flashback table "BIN$b+XkkO1RS5K10uKo9BfmuA==$0" to before drop;
清理回收站:
清除回收站中的单个表:purge table emp
清除整个回收站:purge recyclebin
清除不同的对象回收站:purge user_recyclebin或purge dba_recyclebin
彻底删除一个table: SQL>drop table emp purge; --表不能被恢复了。
3\闪回事物查询:
Sql代码
select * from flashback_transaction_query where TABLE_NAME= 'EMP'

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

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

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

Hot Topics

The retention period of Oracle database logs depends on the log type and configuration, including: Redo logs: determined by the maximum size configured with the "LOG_ARCHIVE_DEST" parameter. Archived redo logs: Determined by the maximum size configured by the "DB_RECOVERY_FILE_DEST_SIZE" parameter. Online redo logs: not archived, lost when the database is restarted, and the retention period is consistent with the instance running time. Audit log: Configured by the "AUDIT_TRAIL" parameter, retained for 30 days by default.

Oracle database server hardware configuration requirements: Processor: multi-core, with a main frequency of at least 2.5 GHz. For large databases, 32 cores or more are recommended. Memory: At least 8GB for small databases, 16-64GB for medium sizes, up to 512GB or more for large databases or heavy workloads. Storage: SSD or NVMe disks, RAID arrays for redundancy and performance. Network: High-speed network (10GbE or higher), dedicated network card, low-latency network. Others: Stable power supply, redundant components, compatible operating system and software, heat dissipation and cooling system.

The amount of memory required by Oracle depends on database size, activity level, and required performance level: for storing data buffers, index buffers, executing SQL statements, and managing the data dictionary cache. The exact amount is affected by database size, activity level, and required performance level. Best practices include setting the appropriate SGA size, sizing SGA components, using AMM, and monitoring memory usage.

The amount of memory required for an Oracle database depends on the database size, workload type, and number of concurrent users. General recommendations: Small databases: 16-32 GB, Medium databases: 32-64 GB, Large databases: 64 GB or more. Other factors to consider include database version, memory optimization options, virtualization, and best practices (monitor memory usage, adjust allocations).

To create a scheduled task in Oracle that executes once a day, you need to perform the following three steps: Create a job. Add a subjob to the job and set its schedule expression to "INTERVAL 1 DAY". Enable the job.

Oracle Database memory requirements depend on the following factors: database size, number of active users, concurrent queries, enabled features, and system hardware configuration. Steps in determining memory requirements include determining database size, estimating the number of active users, understanding concurrent queries, considering enabled features, and examining system hardware configuration.

Oracle listeners are used to manage client connection requests. Startup steps include: Log in to the Oracle instance. Find the listener configuration. Use the lsnrctl start command to start the listener. Use the lsnrctl status command to verify startup.

How to use MySQLi to establish a database connection in PHP: Include MySQLi extension (require_once) Create connection function (functionconnect_to_db) Call connection function ($conn=connect_to_db()) Execute query ($result=$conn->query()) Close connection ( $conn->close())
