Oracle

The most recent deletion of users in Oracle is always an error, and the message is: ORA-00604: Recursive SQL Layer 1 error occurred ORA-00942: Table or view does not exist According to the online solution found that the following test method is

Common functions: Substr and InStr 1.SUBSTR (string,start_position,[length]) to substring, return string Explanation: String Meta string Start_position starting position (starting from 0) Length optional, number of substrings For example:substr

Sql> Select COUNT (*) from V$session #当前的连接数Sql> Select Count (*) from v$session where status= ' ACTIVE ' #并发连接数Sql> Select value from v$parameter where name = ' processes '--maximum number of connections allowed by databaseSql> Show parameter

--Lists the number of employees and departmental numbers for which wages are higher than the average wage in each department, and the select * from EMP E1 by department number, (select round avg (SAL), 2) Sal,deptno from EMP Group by Deptno) E2

Oralce automatically backs up and deletes 5 days before backup in Linux Export script: Export oracle_base=/opt/oracle                  ---Installation path Export oracle_home=/opt/oracle/920              ---Products catalog Export path=/ora/bin:$

Oracle 11g The solution for the locked problem   Why users are locked down may be the following several reasons.  www.2cto.com   1. 　　The attempt to log on more than once was unsuccessful (possibly incorrect password); 　　2. This user is manually

The background: My new entry company less than two months, our project using the Tomcat Profile link Project WebApp, while the Tomcat management data source (that is, in the Tomcat directory Conf\catalina\localhost configuration project path and

My present date format is, to be changed into English needs to enter the command: ALTER session SET Nls_date_language=american;Changed to: If you want to change English to Chinese, you can use the command: Alter session set nls_date_language= '

One 1. Start: The fields in the SQL code exported through Powderdesiger are lowercase and are then imported directly into Oracle. 2.bug: Unable to modify the table structure (in PL/SQL developer)---include adding delete modifications

Steps: (1) Create job (2) Create job Dbms_job.submit (); Submit (Jobno out Binary_ineger,What in Varchar2,Next_date in Date,Interval in varchar2,No_parse in Booean:=false)　　The Jobno parameter is the Binary_ineger returned by the submit () procedure.

How do I see the current number of connections to Oracle? Just use the following SQL statement to query. SELECT * FROM v$session where username Is isn't null Select Username,count (username) from V$session where username is isn't null GROUP by

T_medflow table has 10 million data flowid is primary key has primary key index Total number of statistics Select COUNT (flowid) from T_medflow t Spents: 1.5 seconds Select COUNT (*) from T_medflow t Spents: 1.46 seconds Multiple test efficiency is

Guide: I haven't seen much of Oracle's technical documentation for a long time, and today I read an Oracle Response time optimization and method R. This is the classic book of Optimizing Oracle Performance Classics. The main idea. R represents

  CREATE OR REPLACE FUNCTION f_pinyin (p_name in VARCHAR2) return VARCHAR2 as V_compare VARCHAR2 (100); V_return VARCHAR2 (4000); FUNCTION F_nlssort (P_word in VARCHAR2) return VARCHAR2 as BEGIN return Nlssort (P_word, '

When you use GROUP by Cratetime, but one day there is no data, there will be no data one day. So using the following SQL, you can count out every day. Select To_date (' 2015-06-01 ', ' yyyy-mm-dd ') +level-1 as time

Several ways to migrate Oracle databases We often need to migrate data, migrate to more performance-configurable host OS, migrate to remote rooms, migrate to different platforms, the following describes several Oracle database migration scenarios:

Use of the--oracle trunc () function /************** Date ********************/ 1.select trunc (sysdate) from dual--2011-3-18 today's date is 2011-3-18 2.select trunc (sysdate, ' mm ') from dual--2011-3-1 returns the first day of the month. 3.select

OracelAnalysis function: You can remove the first (last) data in the group First_value () over (partition by ...) Last_value () over (partition by ...) Create TableAtem ( CO1 VARCHAR2(10), CO2 INTEGER ) Insert intoAtem (CO1,CO2) Values(' A ', 1);

1.TRUNC (for dates)The date value that the Trunc function truncates for the specified element.Its specific syntax format is as follows:TRUNC (Date[,fmt]) which Date value FMT date format, which is truncated by the specified element format.

Turn from: http://xo-tobacoo.iteye.com/blog/182791 Summarized below. Using the merge is much faster than the traditional judgment before choosing to insert or update. 1) Main functionProvides conditional updating and inserting of data into a