Database Administrator

SQL> select * from t_char;--------------------A_ BAcbA % BA' BA/BA \ B%_ASQL> select * from t_char where a like 'A _ B ';--------------------A_ BAcbA % BA' BA/BA \ bSQL> select * from t_char where a like 'a \ _ B 'escape' \ ';--------------------A_

1. How to check whether a parameter is dynamic or static We can find the parameter in v $ parameter. Column value format a40; Column name format a20;Select name, VALUE, ISSES_MODIFIABLE, ISSYS _ modifiable from v $ SYSTEM_PARAMETER; Here, the

An Oracle archive log is often full, as the file space occupied by/oraarchive is 100%. Everyone must complain about why Oracle does not have an archive maintenance tool. Many people delete the file directly. Wrong, Oracle has, it is intelligent to

Class. forName ("Oracle. jdbc. driver. OracleDriver"); //. newInstance ();String url = "jdbc: oracle: thin: @ FIG: 1521: yyyy ";// Mydb is the SID of the database, and 10.0.1.1 is the IP address of the database server.String user = "sys as sysdba

Customize a mysql close script according to the working environment   --- 1. Save As/usr/local/mysql/scripts/mysql_env.ini # Set mysql init variablesMYSQL_USER = system # mysql UsernameMYSQL_PASS = 'Password' # mysql logon User password # Check

I. Basic Concepts In a database, the two basic operations on a data are write and read. The distribution has two types of lock control: exclusive lock (X lock) and shared lock (S lock ). Exclusive lock (x lock): If transaction T adds X lock to data

Problem description: [Celladmin @ vrh4 ~] $ CellcliCellCLI: Release 11.2.3.2.0-Production on Sat Jun 14 09:11:08 EDT 2014 Copyright (c) 2007,201 2, Oracle. All rights reserved.Cell Efficiency Ratio: 1 CellCLI> create celldisk all CELL-02559: There

Hadoop version: Hadoop 2.2.0.2.0.6.0-0009 Well, We can do this by building Secondary Namenode, Checkpoint node or Backup node. Example: Assuming you have a Secondary Namenode. 1. Check secondary namenode checkpoint status: Dfs. namenode. secondary.

I introduced the use of triggers in my previous blog, and also mentioned that triggers are a special stored procedure. What is a stored procedure? They What are the differences between the two? In fact, the main difference is that the trigger is

Oracle11g RAC construction in linux (9) 8. Create an ASM warehouse Perform operations on the GUI [Root @ node1 ~] #Su-grid [Grid @ node1 ~] $Asmca // Create two disk groups: Data File disk groups and fast recovery disk groups [Grid @ node1 ~]

FeaturesEvery document in the schema-free MongoDB is a JSON object. Therefore, you do not need to predefine the structure of a set. Each document in the set can have a different structure.By default, all write operations for asynchronous writing to

Reprinted please indicate the source: http://blog.csdn.net/guoyjoe/article/details/30839817 ######### Preparations before recovery1. Perform a Hot Backup select 'alter tablespace '||tablespace_name|| ' begin backup;' ||chr(10)|| 'host cp '|

Source: http://blog.csdn.net/dba_huangzj/article/details/31374037 reproduced Please reference I have seen a discussion on in/exists in the forum. I am too lazy to find the original post. Here I will introduce the recent study summary: Not in and

Although online index reconstruction (alter index index_name rebuild online) has extended the index reconstruction time, it has also given us the ability to recreate indexes online to improve data availability. If errors such as user termination or

The local Oracle database version is 10 Gb, and the remote database version is 11 GB. An error occurred while executing the test query statement after the local database connection was created. The user name and password are correct. SQL> create

Dictionary and dynamic view Oracle dictionary and Dynamic View The oracle service displays all the system statistics in the v $ sysstat view. It also uses many views to display oracle performance and problematic snapshot information. You can query

In such a scenario, after multiple agent Systems (each with their own database) perform their own operations, complex operations will be triggered for the stored procedures of their respective databases, after each operation is complete, you need to

Ora-600 (3020) error was encountered today while restoring a set of test LibrariesSQL> recover datafile 6;ORA-00279: change 1981277 generated at 01/03/2014 14:24:15 needed for thread 1ORA-00289: suggestion:/opt/arch/archive_rj45_834576965.arcORA-0028

If you want to update the start with value of a sequence, you cannot directly change it. An error is returned: SQL> alter sequence seq_xxrs start with 1000; Alter sequence seq_xxrs start with 1000. ORA-02283: unable to change startup serial

1. tablespace description In the previous article (RMAN backup and recovery control file loss), we explained how to control file loss and how to deal with backups in RMAN. This article explains how to deal with offline data file loss. A tablespace