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Flashback transaction query can obtain the historical information of the specified transaction and undo_ SQL from flashback_transaction_query. Through this undo_ SQL, We can query the operations performed by a specific firm, then we can restore

1. Mount the system packages to MNT and install Readline. [Root @ think MNT] # CD Packages/[root @ think packages] # rpm-IVH -- nodeps Readline * preparing... ######################################## ### [100%] package readline-6.0-3.el6.x86_64

Category: 1) Gains and losses directly included in the equity of the owner 2) Gains and losses directly included in the current equity   However, there is no difference between the two. They will eventually constitute part of the owner's

(I) backup The backup and recovery of control files are critical in the database backup and recovery process.The principle is:Back up the control file after the physical structure of the database changesMethods:① Use the operating system command to

(I) Adequate network bandwidth is the basis for log transmission optimization Experience Value budget formula: Bandwidth demand = log generation/0.7X8 Note: Oracle logs are generated in large bytes (8 bits), while the network bandwidth is small

Environment: SQL> select * from v$version where rownum=1;BANNER----------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - ProdSQL> !uname -aLinux think-V30SA 2.6.35-22-generic

Sequence Design Unique but not continuous When the instance crashes, the sequence part number and transaction rollback occur. The sequence part number and concurrent access may be part of the sequence ...... When seq_name.currval is called, the

We all know that level is a pseudo column that represents the level of the current node. For the root node, level returns 1, 2 to the child node, and so on. With level, we can control the number of table scans. The level of the result set obtained

The last two articles: Date and Time parameters (1) Date and Time parameters (2) Here are a few examples:If your answers differ from me, pay attention to the settings of these parameters.① Nls_date_format② Nls_language③ Nls_territoryThe specified

Definition: Row migration: Because of update, the rows become longer, the original blocks cannot be placed, the rows are moved into the new blocks,Line link: The line is too large at the beginning. For example, if you insert a row of bytes, you must

Oracle has many parameter files, but the most important one is database parameter files. Database parameter files include pfile and spfile. Pfile must be manually modified. It is a text file, and spfile is a binary file, which can be changed

Next article: time and date parameters (1) DL returns the long date format based on the settings in the database nls_date_format parameter and nls_language, and the format in the nls_territory parameter.DS in the same short date format as aboveTs is

Environment: [oracle@localhost ~]$ sqlplus -vSQL*Plus: Release 10.2.0.1.0 - Productionsys@ORCL> alter session set nls_date_format='YYYY-MM-DD HH24:MI:SS';Session altered.sys@ORCL> alter session set nls_language='simplified chinese';Session

Question:There are many different types of guinea pigs in the world, some of which have identifiable characteristics. For example, "Abyssinians" has a pleated garlands on the outer skin.Texels has long curly hair. The white crested guinea pig, a

I wrote a blog titled Oracle PL/SQL "Art Appreciation" from if to then. Address: Click to open the link What should I pay attention to when the range is extended to each parallel if condition? When the condition is parallel, can if be

You can set the default session time zone withORA_SDTZEnvironment variable. When users retrieveTIMESTAMP WITH LOCAL TIME ZONEData, Oracle returns it in the users 'session time zone. The session time zone also takes effect whenTIMESTAMPValue is

Initialization parameters related to the primary role Db_name Db_name must be the same in the same DG Environment Db_unique_name The db_unique_name parameter is an added parameter for the coexistence of multiple instances

Environment: [oracle@localhost ~]$ uname -r2.6.18-308.el5xen[oracle@localhost ~]$ sqlplus -vSQL*Plus: Release 10.2.0.1.0 - Production (I) syntax For example:① Reclaim space immediately:Alter table table_name truncate partition partition_name drop

HighThe water level is the upper limit of data in the record segment. Scan the entire table to read the segment header block first, and then find hwm in the segment header block. The following uses the experiment to understand the hwm of oracle

(I) Common Operations ① Back up all databases Syntax: Mysqldump-H host name-P port-u user name-P password (-database) Database Name> file name. SQL Example: Mysqldump-hlocalhost-p3306-urocky-p123456 db_test> bakfile1. SQL ② Full database backup