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Showing posts from November, 2012

Oracle Analytic Functions

AVG(expression) : Returns average value of expression
CORR(expression1, expression2) : Returns the coefficient of correlation of a set of number pairs
COVAR_POP(expression1, expression2) : Returns the population covariance of a set of number pairs
COVAR_SAMP(expression1, expression2) : Returns the sample covariance of a set of number pairs
COUNT(expression) : Returns the number of rows returned by the query

Oracle Aggregate Functions

COUNT(*) : Returns the number of rows returned by the query.
MAX(expression) : Returns maximum value of expression.
MEDIAN(expression) : Returns the middle value or an interpolated value that would be the middle value once the values are sorted.
MIN(expression) : Returns minimum value of expression.
STDDEV(expression) : Returns the sample standard deviation of expression, a set of numbers.
SUM(expression) : Returns the sum of values of expression.
VARIANCE(expression) : Returns the variance of expression.

Using dig tool on windows

dig is one of the finest dns tools for unix and linux admins. ISC (Internet Systems Consortium) provides windows binary for the dig tool. In order to use it from windows machine, download bind zip file from downloads site. Then extract following files to your local folder that is already in your %PATH% environment variable or create a folder in the program files folder and add it to the %PATH% environment variable so you can use it from command line without writing the full path.

Google Cloud SQL

If you are in the IT business you probably know about the Cloud services. Google has Cloud services as well. Nowadays Google introduces a new six month trial at no charge until June 1, 2013. You can sign up here and start experiencing Cloud SQL.

ORA-39083 and ORA-02298

ORA-39083: Object type REF_CONSTRAINT failed to create with error: ORA-02298: cannot validate <constraint_name> - parent keys not found Failing sql is: ALTER TABLE <detail_table_name> ADD CONSTRAINT <constraint_name> FOREIGN KEY <detail_table_column_name> REFERENCES <master_table_name> <master_table_column_name> ENABLE

Kinit failed

winbindd[2753] libsmb/cliconnect.c:1052(cli_session_setup_spnego)
Kinit failed: Clock skew too great

if you encounter this message and can not login via ssh using AD account. This is most probably because server's date and time are not set correctly.

Jboss installation script for Redhat Enterprise linux

First, prepare following files under the Jboss installation folder. Jboss AS zip packages are availeble at and java jdk packages are available at

JUDCon India 2013

JUDCon India is Back - Bigger and Even Better!

JUDCon, the premier developer event "By Developers, For Developers" is happening again from January 17-18 2013 in Bangalore.
The first JUDCon India held early this year was a huge success, and is still the world’s biggest JUDCon to-date. More than 800 attended to hear from the best and brightest developers, and to exchange ideas on JBoss technology, and JUDCon2013:India is going to be even bigger and better!

The JUDCon call for papers is open now through Nov 23, and session tracks will include:
App Servers and App Development
Cloud, NoSQL and Big Data
Rules, Workflow, SOA and EAI
Cool Stuff (that we just can't leave out)

JUDCon2013:India Call for Papers