April 26, 2013

SQL, MY SQL, T-SQL Interview Mostly Asked Question’s

Question (1): simple select query from multiple table using join’s ? The Query is SELECT sg.username,lg.user_id,lg.login_date FROM `sign-up` AS sg LEFT JOIN `log-in` as lg on sg.id=lg.user_id; Question (2): get lasttime login date of each user ? The Query is SELECT sg.username,sg.id, max(lg.login_date) as lastlogin FROM `sign-up` AS sg LEFT JOIN `log-in` as lg on […]

December 21, 2012

MySQL – Sub-query Example, Multiple sub-query, DB De-Normalization, Data Duplication, Data Redundancy

mysql

MySQL – Sub-query Example, Multiple sub-query, DB De-Normalization, Data Duplication, Data Redundancy Example of: Data Redundancy Data Duplication DB De-Normalization Multiple sub-query MySQL – Sub-query Example, Multiple sub-query, DB De-Normalization, Data Duplication, Data Redundancy This post is to show the power of single query which can complete the records by matching and comparing the reference […]

August 1, 2012

Database caching can be a reason of data redundancy

Database caching can be a reason of data redundancy Database caching brings the convenience of result set already fetched and stored in files. I am sharing a situation which i faced twice but still i sometimes forget to avoid. The thing is to validate a record in database that either it exists or not? If […]

Database caching and sql injection prevention

Database caching and sql injection prevention Most probably this term “database caching” will be new for the beginners or the developers who are not using such php frameworks which provide this facility. I am talking about one of those which is codeigniter. Database caching in fact caches those queries which fetch the records from database […]

July 31, 2012

Database Optimization Experience – Rackspace Cloud

Database Optimization Experience – Rackspace Cloud Conversation: Hello, It has come to our attention that the database xyz has been running some queries that take an extremely long time to complete and have started to become detrimental to the shared resource that the database is hosted on. At this time, we have not imposed any […]