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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

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.

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