Like w3schools

http://www.tutorialspoint.com/index.htm

Database fundamentals

http://crazy4db.blogspot.in/2012/04/overview-of-database-indexes.html?goback=%2Egde_50812_member_108321673

Diff b/w Interface and abstract class

http://widwebway.com/en/blog/?p=30&goback=%2Egde_50812_member_106688011

Joomla Security Tips

http://www.cio.com/article/703841/13_Tips_for_Better_Joomla_CMS_Security?page=2&taxonomyId=3042

http://bodvoc.com/index.php?option=com_content&view=article&id=43:improving-your-joomla-htaccess-file&catid=2:joomla-security&itemid=3