Database Administrator

When I look at the program, I find that as long as it is a piece of SQL statement, it is basically written like this:Where 1 = 1I checked the reason online: I cannot determine whether there is a statement after where. I need to add 1 = 1. If there

Today, when I sorted out the data, I found that the Postgre version was used directly to understand compression, and The for expert only.For the purpose of testing, a copy of sql-8.3.3-1-binaries-no-installer.zip is directly downloaded from the

Server. ScriptTimeout = 1000000'Xtype = 99 ntext is similar to text. The difference is that the ntext type adopts the unicode standard character set.'Xtype = 35 text is used to store a large amount of text data.'Xtype = 231 nvarchar is used to

Today, due to work needs, we need to find different record values under a certain field in the database. The very simple problem is too complicated and depressing, the reason is that a command of SQL has been forgotten, and the problem has been

I. mathematical functions 1. Absolute ValueCopy codeThe Code is as follows: S: select abs (-1) valueO: select abs (-1) value from dual 2. INTEGER (large)Copy codeThe Code is as follows: S: select ceiling (-1.001) valueO: select ceil (-1.001) value

Linux database instance startup settings 1. Modify/oratab [Root @ org54 ~] # Vi/etc/oratab -- change N to Y, as shown below: # This file is used by ORACLEutilities. It is created by root. sh # And updated by the Database ConfigurationAssistant when

1: The first method is very simple. c3p0.driverClass=com.mysql.jdbc.Driverc3p0.jdbcUrl=jdbc:mysql://localhost:3308/databasec3p0.user=rootc3p0.password=root File Name: c3p0. properties (put under the src directory) // The program I wrote is

Install: Oracle installation has many tutorials on the Internet, which are explained in detail. I will not go into details here. I only provide two links, which may be helpful: Oracle Installation and simple configuration. free installation of

 Ing a Cluster Node on Linux and UNIX Systems 1. Check whether the node to be deleted is active or pinned.$ Olsnodes-s-t If pinned, crsctl unpin css-n unpinned corresponding node 2. Disable the application resources and processes of the

Test the DG Environment Environment Name Master Database Slave Database Host Name Bjsrv Shsrv Software Version RedHat performanise5.5, Oracle 11g 11.2.0.1 RedHat performanise5.5, Oracle 11g 11.2.0.1

1. sum over usage Sum (col1) over (partition by col2 order by col3) The above function can be understood as: grouping by col2 (partition), sorting by col3 (order), and continuous addition (sum) Table a has the following content:B C D02 02 102 03 202

MongoDB study Note 1: download and install MongoDB Taking advantage of these few days, I am ready to learn about the MongoDB database. Today I have simply learned how to download and install MongoDB and created a data warehouse that stores MongoDB.

Restore database code in Linux: 1. Create an empty database cddlMysql> create database cddl;Query OK, 1 row affected (0.00 sec) 2. Restore the database[Root @ chicago mysqlsoftware] # cd/etc/rc. d/init. d[Root @ chicago mysqlsoftware] # cd/etc/rc.

Zookeeper Method 1:[Root @ vmrac1 ~] # Su-grid[Grid @ vmrac1 ~] $ Sqlplus/as sysasmSQL * Plus: Release 11.2.0.3.0 Production on Thu Jul 3 09:36:27 2014Copyright (c) 1982,201 1, Oracle. All rights reserved.Connected:Oracle Database 11g Enterprise

Select to_char (sysdate, 'yyyy-mm-dd hh24: mi: ss'), to_char (trunc (sysdate), 'yyyy-mm-dd hh24: mi: ss ') from dual t; -- sysdate and trunc (sysdate) are different. sysdate at 00:00:00 of the current day is equal to trunc (sysdate) select trunc

1. Uninstall the old MySql version 1. rpm uninstall: 1> check the installation package: Rpm-qa | grep mysql 2> normal deletion: Rpm e mysql-5.6.16.rpm 3> force Delete. If you are prompted to have other dependent files when you use the preceding

The related steps about how to create a phisical standby database please refer: http://blog.csdn.net/waterxcfg304/article/details/35991771   /* How to create a logical standby database based on a physical standby database */ The following is the

133 export the database elink: dbexport-o/home/ap/dcclink/. shan/194/elink; 132 import the database elink: dpimport-c-ddatadbs-I/home/ap/dcclink/. shan/elinkelink.   The problem is as follows: 1. The type of your terminal is unknownto the

This error often occurs in Oracle data after an illegal shutdown: EXP-00056: ORACLE error 1033 appearsORA-01033: ORACLE initialization or shutdown in progressUser:Password: This is obviously because the database cannot be started, but the database

1. Why do we need to enable the Connection when using jdbc? once it is used up, it is immediately closed. What will happen if my Connection is opened at the beginning and closed at the end of the entire program? 2. Why use the connection pool? When