Database Administrator

Notes for setting the target database to archive in Oracle 1. Connect to sysdba SQL> conn/as sysdba 2. Check whether the instance is archived. SQL> select dbid, name, log_mode from v $ database; 3. Set archiving Parameters SQL> alter system

MySQL dual-host hot backup is often used in Linux Server lvs load balancing and dual-host hot backup applications. The installation and configuration process is as follows: 1. Install MySQL # Cp

The VM for Linux prefers system cache over application memory. What does this mean? The best way I can explain is by example. Imagine you have 32 GB of RAM MySQL is set to take 20 GB of RAM for a process based buffer and up to 6 M for the varous

1. type conversion functions: decimal, double, Integer, smallint, real, Hex (arg ), Date, time, timestamp, char, varchar Common examples: -- Convert to string type Oracle: select to_char (15.5000) from dual; DB2: select char (15.5000) from sysibm.

Use Rails in Ubuntu to connect to Oracle: 1. Instant Client Package-Basic "and" Instant Client Package-SDK 2 mkdir/usr/local/share/oracle Mkdir/usr/local/share/oracle Cd/usr/local/share/oracle Unzip path/to/instantclient-basic-XXXX-10.1.0.X.zip

After Oracle successfully acquires Sun, it will have two ides: NetBeans and JDeveloper. In the long run, Oracle is likely to support only one of them. Which one should it be? Adam Bien, a professional consultant, lecturer, and software architect,

Copyright statement: original works can be reproduced. During reprinting, you must mark the original source, author information, and this statement in hyperlink form. Otherwise, legal liability will be held.Http://tianzt.blog.51cto.com/459544/212606

I. experiment environment: Virtual machine version: Workstation 6.5-7.0 virtual machine RedHat version: Red Hat Enterprise Linux Server release 5.4 (Tikanga) Kernel version: 2.6.18-164. el5 Log on to linux as a root user. The default language is

1. Connection The default mongodb port is 27017. Therefore, we can connect to mongodb: $ mongodb = new Mongo ('localhost') or specify the IP address and port $ mongodb = new Mongo ('192. 168.127.1: 27017 ') the port can be changed. If mongodb

Nulls first and nulls last are syntaxes supported by Oracle Order. If the expression Nulls first is specified in Order by, the null value of the record is ranked first (whether asc or desc) If the expression Nulls last is specified in Order by,

Use the built-in functions of mysql: INET_ATON (expr)Given the dotted-quad representation of a network address as a string, returns an integer that represents the numeric value of the address. Addresses may be 4-or 8-byte addresses.Mysql> SELECT

Resolving Oracle listener startup errors 1, TNS-12547: TNS-12547: TNS: lost contactTNS-12560: TNS: protocol adapter errorTNS-00517: Lost contactLinux Error: 104: Connection reset by peer No 127.0.0.1 localhost is found in/etc/hosts. Modify/etc/hosts

First, let's look at an Oracle 10g table to create an SQL statement, which is the default value:Create table sys. QS(USERNAME VARCHAR2 (30 BYTE) not null,USER_ID number not null,CREATED DATE NOT NULL)TABLESPACE SYSTEMPCTUSED 40PCTFREE 10INITRANS

The mysql configuration file is my. cnf, which is located according to the settings during installation.When the mysqld service is started, the configuration file is read in a certain order by default. [Root @ zhu2 ~] #/Opt/mysql/libexec/mysqld --

For SQL optimization, you can use SQL tuning advisor to achieve automatic SQL optimization and adjustment. For PL/SQL code, there are both SQL code and PL/SQL code. It is far from enough to use only 10046 events, because the SQL time may be very

Usage: Require_once ("backdata. class. php ");$ Link = @ mysql_connect ("localhost", "Database Name", "password") or die ('could not connect to server .');Mysql_query ("use cms", $ link );Mysql_query ("set names utf8", $ link ); $ Dbbck = new

Today, we found that the Oracle database is very slow. We can see that a large number of processes are waiting for the log file switch (checkpoint incomplete). The usage of log files is as follows: SYS @ TEST15> select group #, sequence #, bytes/1024

These three table join methods are the most basic connection methods for Oracle:Principle of nested loop joinHash join Principle Sort merge join) Number of visits: both tables can only be accessed 0 times or 1 time.Whether the driver table is

An error is reported when srvctl is executed. [Oracle @ rac01 bin] $ srvctl /U01/app/oracle/product/10.2.0/db_1/jdk/jre/bin/java: error while loading shared libraries: libpthread. so.0: cannot open shared object file: No such file or directorySrvctl

1. Install redis -------------------------------------------------------------------------------- Home: http://redis.io/: Http://download.redis.io/download the latest source package (current latest stable version 2.6.16)# Wget