Oracle

DG is divided into the master database and the slave database. We also guess that it belongs to the interaction between primary and standby, so the switchover between primary and standby: However, switching is divided into switchover and failovers.

After I restart my computer recently, I open two oracle-related services but cannot connect to them. Sometimes open Z producer? Http://www.bkjia.com/kf/ware/vc/ "target =" _ blank "class =" keylink "> vcmFjbGW3/release + zvHXtMysyLTP1Mq + release +

Statistical information is very useful. Without it, the SQL optimizer is like a clever man! A good and efficient SQL Execution Plan depends on real statistics. However, in some cases, for example, to compare the execution plans of the production

In Windows, Oracle backs up data every night through EXP and retains the backup data for ten days. 1. Create the backup script oraclebackup. bat Contents: @ Echo offEcho deletes the backup file and log 10 days ago. Forfiles/p "E: \ oraclebackup"/

  Processing certain data requires reading data from Oracle Because there is not much Data, it is simple and convenient to directly use System. Data. OracleClient Add references, write SQL statements in one breath, and report an error immediately

Indexes are common database objects. The purpose of creating indexes is to increase the record retrieval speed. Whether or not it is set properly affects the performance of Database applications and databases. Although there are a lot of materials

Oracle and firewall settings To access the windows oracle database after the firewall, simply open the fixed TCP port. The root cause of this problem is the BT design of the windows oracle Database (this problem is not found in unix/linux ).I.

LPAD (c1, n [, c2]) [function] fill string c2 on the left of string c1, until the length is n, [parameter] C1 string n append total length c2 append string, default is space [Return] character type [description] If c1 length is greater than n,

Generally, rownum, that is, pseudo columns, is used to specify multiple data entries to be displayed, For example Select linename from aced where rownum However, you should note that if the retrieved data contains duplicate data, rownum cannot

Adding virtual memory in linux solves the problem of insufficient swap space Add a SWAP file: 1. view the current virtual memory [Root @ ora11gr2 ~] # Free-mTotal used free shared buffers cached Mem: 2026 217 1809 0 11 126 -/+ Buffers/cache: 78 1947

Oracleinitialization Solve the Initialization error cocould not load problem. Another problem occurs when the login interface is complete with information for logon.ORA-12154:TNS: cocould not resolve the connect identifier specified, that isThe

Oracle packages are divided into package specifications and packages I. Create a package specification first Create or replace package p_pagewithgroup is-- Author: Xiao Wei-- Created: 2014/3/18-- Purpose: group paging ProcessTYPE type_cur is ref

Check whether the tablespace in the database is idle and used to add data files to the tablespace. View the percentage of tablespaces used Code   Select. tablespace_name,. bytes/1024/1024 "Sum MB", (. bytes-b.bytes)/1024/1024 "used MB", B. bytes/102

The original understanding of the index only knows that the index can be based on one or more columns. The B-Tree index does not contain null, however, in some cases, we need to use the where column name is null to find some data. At this time, the

1. Oracle users addedCopy codeThe Code is as follows:Create user lisi identified by lisi; Note: create user is the database user created, followed by the user name, and identified by is the user password set 2. Grant the "connection" database

Oracle Move command Summary Starting from 8i,OracleStart to provide the Move command. We usually use this command to move a table segment from one tablespace to another. Moving is actually a physical copy of data between blocks, so we can reduce the

--- Indicates flashing back to the database --- Use a flashback table to restore the table content to a specific time point in the past --- Restore from the deleted table --- Use the flashback query to view the database content at any point in time -

Create a tablespace: Create tablespace nameLoggingDatafile 'd: \ oracle \ product \ 10.2.0 \ oradata \ orcl \ tablespace name. dbf'Size 100 mAutoextend onNext 2 mExtent management local; Create a user: Create user Login Name Identified by

(1) view character sets (all three are equivalent)Copy codeThe Code is as follows:Select * from v $ nls_parameters where parameter = 'nls _ CHARACTERSET'Select * from nls_database_parameters where parameter = 'nls _ CHARACTERSET'Select * from props $

1. Copy the table structure and data:Copy codeThe Code is as follows:Create table table_name_new as select * from table_name_old2. copy only the table structure:Copy codeThe Code is as follows:Create table table_name_new as select * from