Database Administrator

In some cases, the or condition can avoid full table scan. 1. If the where statement contains the or condition, the myisam table can use indexes, but innodb does not. 1) myisam table: Create table if not exists 'A '( 'Id' int (1) not null

[Oracle @ bi11g bin] $./sqlplus/nolog SQL * Plus: Release 11.2.0.1.0 Production on Fri Dec 1618: 39: 36 2011   Copyright (c) 1982,200 9, Oracle. All rights reserved.   SQL> conn/as sysdba Connected. SQL> show parameter memory   NAME TYPE VALUE ------

[Root @ localhost libs] # wget http://pear.php.net/get/oci8-1.4.5.tgz[Root @ localhost libs] # tar zxvf./PDO_OCI-1.0.tgz[Root @ localhost libs] # cd PDO_OCI-1.0[Root @ localhost PDO_OCI-1.0] #/usr/local/php/bin/phpize[Root @ localhost PDO_OCI-1.0] #.

1. When writing a query statement, make sure that the Java type matches the database type. If not matched, the query efficiency may be affected. For example: 2 when writing an insert statement, if the target field may be blank, you can use the

The OS version used is CentOS 5.7, and the original Oracle version is 10.2.0.1.0. When upgrading Oracle to 10.2.0.4, the system always prompts that the operating system fails to be checked. Change the/etc/RedHat-release content to Red Hat Enterprise

There are two ways to store files in Mongodb in the GridFSB mode: 1. Command Line program files 2. client-side driver programming (using Java as an example) Related reading: MongoDB cluster configuration (sharding with replica set) Add a shard

The following error is reported when the standby uard standby database starts a recover:ORA-16014: log 4 sequence #1 not archived, no available destinations Solution:First lookSQL> show parameter db_recovery NAME TYPE VALUE---------------------------

When you use impdp, you will find that many Parameter options are different from imp. For example, you cannot find the fromuser and touser parameters, you cannot find the ignore parameters, and parameters such as indexes no longer exist.Of course,

First, the experiment environmentTwo Linux servers with MySQL installed can be YUM installed, Binary packages installed, or source code packages compiled. Then, the master-slave synchronization of the two MySQL servers is realized, how to Implement

Steps 1-7 below are for the root user 1. hardware environment requirementsCheck content minimum value check command referencePhysical memory 512 M # grep MemTotal/proc/meminfoSwap space 1.0 GB or 2 times memory size # grep SwapTotal/proc/meminfo/Tmp

1. Use stored procedures (1) create a packageSQL code CREATEORREPLACEPACKAGE TESTPACKAGEAS TYPE Test_CURSORISREFCURSOR; EndTESTPACKAGE; (2) create a Stored Procedure SQL code CREATEORREPLACEPROCEDURETESTC (p_CURSOROutTESTPACKAGE.

PairMongoDBEveryone who knows about MongoDB has a headache.Global lock(Read/write lockAnd allow concurrent reads, while writing will block all reads and writes. The worst thing is that this lock is not at the table level, not at the database level,

1. Unzip the shortcut key installation package: Root@www.bkjia.com ~ # Tar-zxvf rlwap-0.30.tar.gz Root@www.bkjia.com ~ # Cd rlwap-0.30 2. Perform the Configuration: Root@www.bkjia.com ~ #./Configure Root@www.bkjia.com ~ # Make

I. EM (Enterprise Manager)9I provides Images Written by oem java, Which is ugly and can be renamed EM after 10 Gb.Em web-Based Enterprise Manager provided by Oracle10GPowerful functions, but not the main interface for DBA routine maintenanceAfter

In Oracle databases, Oracle Auto-increment fields are not supported, but can be implemented through triggers and sequence. Assume that the [Table test] keyword segment is id and a sequence is created. The code is:[Html] Create sequence seq_test

When installing with mysql-5.0.51a-linux-i686-glibc23 today, a little bit of problem occurs All programs have been completedHowever, when mysqld_safe is started, it is proposed as follows: [Mysql @ cyou-inc ~] $ Mysql_bin/bin/mysqld_safe: line 199:

Just now, another careless operation was executed on the Slave to change the database schema. The result is that the status of this server in mmm_control has changed to: REPLICATION_FAIL. First, use writer to perform the same operation to ensure the

I tried phpMyAdmin a few days ago. It is fully functional and easy to use. I have seen some MongoDB management tools before, so I want to give it a try. Rock_mongo has been selected, and it turns out that the selection is correct. There are also

The method for starting Scott user in Oracle. In Oracle10g, (g stands for 'network') the Scott user in the database is locked during installation. When installing Oracle, you can directly unlock the user. If you forget to unlock the user, you can

In general, the foreign key of the Oracle sub-table needs to be indexed, If no index is added to the foreign key, modifying the parent table will lock the child table. 1. Update the primary key of the parent table, and the child table will be