Oracle

--To view the maximum number of connections to a databaseSelectValue fromV$parameterwhereName ='Processes';--change the number of database connectionsAlter systemSetprocesses = theScope =SPFile;--to view locked

------------------------------------------type conversion function------------------------------------------------Automatic type conversion, ORACLE can automatically change the following according to the specific situation:* String to Numeric*

-----------------------------------------------character function-----------------------------------------------1:asciiReturns the ASCII value of a string　　SELECT ASCII (' A ') from DUAL;SELECT ASCII (' a ') from DUAL;--2:chrReturns the ASCII

The following garbled behavior occurs because Oracle does not support the Chinese character setResolution Steps　　1. Open the registry to find the Oracle---"Key_oraclient11g_home---" NLS. LANG modifies the value to simplified Chinese_china. ZHS16GBK,

--Each month in the time period, {0}: Start date, {1}: End Date Select To_char (Add_months (To_date ('{0}','yyyy-mm'), ROWNUM-1), 'yyyymm'As monthlist from DUAL CONNECT by ROWNUMMonths_between (To_date ('{1}','yyyy-mm'), To_

The dump function is used to determine whether a character type in a string belongs to number or stringStored ProceduresCreate or Replace procedurePro_isnum (i_stringinch varchar2, O_note outvarchar2) asstring1varchar2( +);--after the field is

SQL Duplicate Record Query methodAugust 14, 2008 Thursday 21:01 SQL Duplicate record query1, look for redundant records in the table, duplicate records are based on a single field (Peopleid) to determineSELECT * from Peoplewhere

One, sys users and system usersThe Oracle installation automatically generates SYS users and system users(1), sys user is superuser, has the highest privileges, has the SYSDBA role, has the rights to create database, the user's default password is

6 errors and solutions most frequently encountered by Oracle installations[ take 8.1.6 as an example]:1 , Ora-12541:tns: No listenercause: There is no boot listener or the listener is corrupted. If the former, use the command net start

1. Querying the character set of the Oracle server sideSql> select userenv (' language ')  from dual; USERENV (' LANGUAGE ')----------------------------------------------------American_america. zhs16gbksql>  or

Tag: Group does not produce order by STS first syntax value OraSub-query:A definition is a query that is nested within a query.Subqueries can be present in many places, such as columns, tables, conditions, etc.Grammar:SELECT (sub-query)From

　　Other database objects:Sequence (SEQUENCE)Indexing (Index)Views (view)1. Sequence (SEQUENCE)Corresponding Database dictionary: user_sequences　　　　Role: A database special object used to produce a unique valueTo create a sequence syntax:Create

One, sys users and system usersThe Oracle installation automatically generates SYS users and system users(1), sys user is superuser, has the highest privileges, has the SYSDBA role, has the rights to create database, the user's default password is

Conversion Functionsstring , values and dates can be converted between three types of data . No. Name of function Meaning 1 String To_char ( column | date, format ) Convert a date or number to a

YUM Script#!/bin/bashrm -rf/etc/yumrepos.d/*echo "[yum]name=yumbaseurl=file:/// Mnt/enabled=1gpgcheck=0 ">/etc/yum.repos.d/yum.repomount/dev/cdrom/mnt &>/dev/nullyum clean Allyum MakecacheOracle Script#!/bin/bash# Configure

Create a new TXT fileThe contents are as follows@echo off sqlplus abc/[email protected] @c:\users\administrator\desktop\abc.sql exitWhen you are finished, change the file suffix to. bat, and the abc.sql is executed when you

Oracle Start with keyword prefaceDesigned to document a variety of issues encountered in Oracle usage. I also hope to help people who have the same problems as me.Start with (tree query)Problem Description:In the database, there is a more common

SELECT * from Sh_gonghuo_renyuan as of timestamp to_timestamp (' 2017-11-17 16:00:00 ', ' yyyy-mm-dd hh24:mi:ss ');--3, recovering deleted and committed dataALTER TABLE Sh_gonghuo_renyuan enable row movement;--flashback table Sh_gonghuo_renyuan to

1.create user username identified by password;//username and password Oracle, Oracle2.grant CONNECT,RESOURCE,DBA to username;//authorized Grant CONNECT,RESOURCE,DBA,SYSDBA to username;3.connect username/password//entry.4.select

Methods and precautions for using forced indexes in Oracle, oracle Indexes Oracle forced Index In some scenarios, ORACLE may not automatically take the index. In this case, if the business is clear, you can try to use a forced index to test the