Oracle

Primary and Standby library switching is mainly in two cases, switchover and failover, both of which need to be done manually.One is switchover (planned switchover, no loss of data)The second is failover (the main repository switch role is required

Like whatField A: ' Ab,cd,ef,gh 'Field B: ' Aa,bb,cc,dd ' does not have the same valueField A: ' Ab,cd,ef,gh 'Field B: ' Aa,bb,cd,dd ' has the same value CD1.CREATE OR REPLACE TYPE ty_str_split is TABLE of VARCHAR2 (4000);2.CREATE OR REPLACE

The detailed procedures are listed below:1. Log in to the database via the SQL Plus command.Enter Sqlplus "Login username/password as login type" on the command line to log in, the system built user name commonly used is sys, password is set during

In the update operation for a table, in many cases, you need to refer to data other than the table you want to update in an expression. Like SQL Server provides the FROM clause of the update, you can connect the table you want to update with its

First,Oracle Client-to-server communication mechanism after the Oracle product installation is complete, both the server and the client need network configuration to enable network connectivity, server-side configuration listeners, and the client to

The previous projects were developed using the MySQL database, and are now in the new company, beginning to reach the Oracle database, and have not been contacted before, to squeeze time to learn.I. The concept of a relational databaseThe relational

An index can consist of one, two, or more columns. An index on two or more columns is called a composite index. The first column of a composite index is called a leading column (leading).Reprinted from http://yijiangyanyu.iteye.com/blog/1677694An

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One, virtual table　　Dual, only for operation, no data.Second, String function　　1: string concatenation function concat (P1,P2) or | | ；Eg: concatenation of the string "Hello" and "Kitty"Select concat (' Hello ', ' Kitty ') from dual or select '

1 Common commands 1 Sqlplus Scott/[email PROTECTED]:1521/ORCL The back not add ; Sqlplus sys/oracle as SYSDBA "Password Authentication" Sqlplus User name arbitrary/password any as SYSDBA

Oracle Multi-result set nesting loop processing optimization--Poor performancebegin forAinch(SelectId,name,sex,idcard frompeople) Loop forBinch(SelectId,name,sex,idcard from中文版) LoopifA.idcard=B.idcard Then --Do something End if;

View: A query statement that can correspond to one or more tables-- create a view without querying payroll Create or Replace View V_normal as Select e.empno,e.ename,e.job,e.mgr,e.hiredate from EMP E Order by E.hiredate--Query results as a table

Create the Oracle service file under the/etc/init.d/directory with root user Cd/etc/init.dvi oracle11g Add the following #!/bin/bash# chkconfig:345 10# Description: Startup Script. For Oracle databasesexport oracle_base=/u01/app/oracleexport

First, describeThe execution plan could not be viewed during the review of the execution plan test, and was found to be dbms_xplan.display because a set autot on was turned on during the test, and after it was closed (set Autot off), the Execute

ProfileThere are always problems when Oracle and EF work together, so here's a summary of the solution.Schema schemaPeople who have used Oracle should know that Oracle's user name is typically its schema name, and if you are building an EDMX file in

----Querying the current database for blocking SQLSelect COUNT (*), Sql_id,min (Sql_exec_start), sql_child_number from v$session where status= ' ACTIVE ' GROUP by Sql_id,sql_ Child_number ORDER by 1, 3;---Blocking SQL content based on SQL_ID

Environment: Oracle 11.2.0.4customer Demand: The main background is that there are many business user names in the database, and because some users lack security awareness, and even directly set their own password as the same as the user name, the

1, the server's monitoring configuration: The default port number 1521Start and turn off monitoring: Lsnrctl start|stop [listerer listener name]It is common to start the listener before starting the instance, or you can register statically in the

As shown in the following formula, 2015 to the current year (2018) of the annual range, the current year is obtained by the system, using the sysdate and function to_char,to_date.Of course, the current year can also be replaced by a specified

Null value operation:　　NULL means null.First, the situation: 1: Any field in the table can be a null value by default. 2:NOT NULL means non-null, a field with a constraint set to a non-null constraint, must have a valid value, and cannot be empty.3: