Database Administrator

The following two system tables are used to query the table where a constraint is located. User_constraints constraints table, which records all constraints of the user. Such as non-null and index. User_cons_columns constraint field table, which

Kfed and kfod in CRS_HOME/bin are very useful tools for checking ASM disk. -Bash-2.05b $ kfed-helpAs/mlib ASM Library [asmlib = 'lib']Aun/um AU number to examine or update [AUNUM = number]Aus/z Allocation Unit size in bytes [AUSZ = number]Blkn/um

Usage conditions:For Linux or Solaris machines, we recommend doule buffer cache in AWR, and db file sequential read is the top wait event. Size:2-10 times the buffer cache. It cannot be less than 2 times. If ASMM is used, 2-10 times the

Environment:The MySQL database version on the master and slave servers is 5.1.34.Host IP: 192.168.0.1Slave IP Address: 192.168.0.2 1. MySQL master server configuration1. Edit the configuration file/etc/my. cnf# Make sure it is as downstreamServer-id

Introduction: We may not be familiar with the range, hash, and list partitions of Oracle, but there may be many questions about what scenarios each partition applies, so what should we pay attention to when selecting different partitions? Why? What

You must use the TO_DATE function.SQL codeTO_DATE ('2017-08-24 00:00:00 ', 'yyyy-MM-DD HH: mm: ss ') The results reported two errors in the ORA-01810 format code. after an online query, it was found that there was a problem with formatting the

In general, the following two methods are used to perform a fuzzy query on the name field of the tb table in the Oracle database:1. select * from tb where name like '% XX % ';2. select * from tb where instr (name, 'xx')> 0; If no index is added to

Today, I was about to leave after work. As a result, the developers said that the data in a test table suddenly disappeared and that no one should delete the table, ask me if it is an Oracle Bug (this is a bit of a problem, I can think of it all,

Flashback is a technology applied from Oracle10g. It can be used to view the data of a database at a time point in the past, restore the database to a State at a time point in time, and restore tables that have been accidentally deleted. Use it to

[Root @ localhost home] # vi test. sh#! /Bin/shOracle_HOME =/oracle/ora10/productExport ORACLE_HOMEUserpwd = test/test@10.11.0.235: 1521/ora10g$ ORACLE_HOME/bin/sqlplus-S $ userpwd Alter session set nls_date_format = 'yyyy-mm-dd hh24: mi: ss

1. Create a connection userMkuser id = 1028 pgrp = db2user1 groups = db2user1 home =/home/fmusx core =-1 data = 491519 stack = 32767 rss =-1 fsize =-1 fmusx 2. Create a Development DatabaseDb2 create database SX3 automatic storage yes

Today, we tested the restoration method for Oracle after deleting table data. There is a table in the maintenance test of the oracle production system. The data in the table is deleted and commit. The service cannot be interrupted (the database

An article library contains two tables: category and article. There are 10 classified data entries in category. There are 0.2 million articles in articles. There is a "article_category" field in article that corresponds to the "category_id" field in

Oracle does not have auto-incrementing primary keys like Mysql and SQLSERVERHowever, you can use other methods to replace the automatic primary key method, including sequence creation and trigger creation.Here we will focus on sequence

After Oracle is installed, there is a default database. In addition to this default database, we can also create our own database. For beginners, you can use the 'database Configuration asmap' Wizard to create a Database to avoid troubles. After

A service has been installed.MysqlInstance.Mysqld_multiCommand to add an instance 1. Assume that there is an existingMysqlInstance, itsBasedirIs/Usr/local/mysql,The data directory is/Usr/local/mysql/data,The configuration file is/Etc/my. cnf # Mkdir/

Wmsys. the function of wm_concat is to merge multiple rows into one row. For example, if A person buys three stocks A, B, and C, we will record three data records normally, now we want to display the stock of this person with a piece of data. This

The front-end can select multiple different conditions under the same field, which involves the problem of SQL statement concatenation. The following is a method for processing query conditions using regular expressions. It is the simplest method I

Install postgresql on openSUSE and record the steps below. Read more: Install Mono on openSUSE and release ASP. Net programs Environment I tested the installation of postgresql 8.4.6 on openSUSE 11.3, and the installation of postgresql 9.0.3 on

Enable memory allocation for Oracle databasesTotal System Global Area 389189632 bytesFixed Size 1345156 bytesVariable Size 243272060 bytes 4194304 + 4194304 + 159383552 = 75497472 java_pool large_pool pga_aggregate_target shared_pool_size 243272060-2