Oracle

Aggregation functions------------------------------------------aggregate function-----------------------------------------------1:avg (distinct| All)All means that all values are averaged, and distinct only averages the different values.SELECT AVG

The Execute shutdown immediate command does not respond when you restart the Oracle database server on the server[[email protected] ~]$ sqlplus/nologsql*plus:release 11.2.0.1.0 Production on Thu December 7 22:16:31 2017Copyright (c) 1982, Oracle.

Rest a day, finally can catch breath, usually teacher teach very good but progress also pretty fast, a wandering almost can't keep up with, so Sunday rest basically also can only use to sleep 23333 ....This week, I told you something new, a

--StartWe all know that numbers can be added, minus, multiply, divide, and so on. So, could the date be? The answer is that the date can only be added, minus operations.Before starting the operation date, let's look at what date data types are

Component Data Dictionary tables and viewsDatabaseV$database, V$version, v$instanceShared ServerV$queue, V$dispatcher, V$shared_serverConnection PoolingDba_cpool_info, V$cpool_stat, V$cpool_cc_statstablespacesUser_free_space, Dba_free_space,

When you create the database, the SYS login in the Oracle database is unlocked with the following SQL Sql*plus tool.1, through the data dictionary dba_users, check the lock status of the Oracle account, as follows: (v wherein, open indicates that

Query and delete duplicate records of the SQL statement  1, find redundant records in the table, duplicate records are based on a single field (ID) to determine the  select * from table where Id in (select ID from table group Byid have COUNT (ID) > 1

First, Oracle downloadOfficial Next AddressHttp://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html Win 32-bit operating system:/HTTP

Method One:1, set/etc/grub.conf file, add Transparent_hugepage=never, in system boot is disabled[Email protected] ~]# cat/etc/grub.conf# grub.conf generated by Anaconda## Note that you don't have the to rerun grub after making changes to the This

"Bo Main Note: Database aspects itpub website and blog content is very rich and informative"Reprint Source Itpub BlogOften people will ask: the original data in the Users table space, I want to put it into the app table space, I have modified the

I. Installation of the Oracle database (installed in the XP system of the virtual machine)1. Install the virtual machine2. Install the XP system inside the virtual machine, the following steps are made within the virtual machine3. Double-click Setup.

Installing virtual machines Reference: https://opensourcedbms.com/dbms/installing-cent-os-6-3-linux-in-oracle-virtual-box-ssh-access/To set up network port forwarding:Note: If the port mapping does not take effect, the executable command

It is easy to understand that a company is likened to a server, and the database is a department in the company.1.SID: A database can have multiple instances (such as RAC), and the SID is used to identify the name of each instance within the

Common functions: Substr and InStr1.SUBSTR (String,start_position,[length]) to substring, return stringExplanation: String meta stringsStart_position start position (starting from 0)Length optional, number of substringsFor example:substr ("ABCDEFG",

ORA-01578 is a block of physical bad blocks/corruption, different from the logical corruption/bad block, usually accompanied by ORA-1110 appear, once Oracle read to the existence of a corrupted block will be reported caused By:java.sql.SQLException:

The difference between Oracle and MySQL primary key, index and paging, learning Oracle's friends can refer to the followingDifference:1, primary key, Oracle can not achieve self-increment, MySQL can achieve self-increment.Oracle new sequence,

Recently, there is a task to modify an older project, the branch does not have this project database-related backup, so you need to export the database from the formal environment backup out of the local deployment installation, before the other

2017-05-10First, configure the ORACLE_UNQNAME environment variableIi. reconstruction of the EM database: Emca-repos recreateThird, configure the EM account password: DBSNMP, SysmanIv. Configuring the EM Database: Emca-config Dbcontrol dbV. Solve the

Oracle database startup failure due to time reversal of VM virtual machineThis article is an original article. If reproduced please specify the source:http://blog.csdn.net/msdnchina/article/details/38782163Alert logs directly on the database:Fri APR

1. On page 3rd of the directory, "What does the 6.4.1 prompt action do" changes to "what the commit operation did".The following is an erratum to the text1, P35 the first line of the first paragraph, modify the "previous line" to "next line."2. P49