Monday, August 18, 2014

NoSQL Databases

       NoSQL is next generation DBMS which is used to store and retrieve the data which does not have specific format or table like structure. NoSQL database is also called as “Not only SQL” to emphasize that it does not use SQL language but It uses SQL-like language. The original intension has been modern web scale databases. The movement began in early 2009 and growing rapidly. NoSQL databases are mostly addressing some of the points:-
·         Non-relational
·         Distributed
·         Open source
·         Horizontally scale

          As we Know there are different types of Database Management System and RDBMS is most commonly used database management system. If we go back in history, first flat file systems were created then in 1970's Codd came up with Relational theory and based on that relational databases were developed. The problem was that in flat file system there was no standard way of storing data and no standard way of communicating with data. Everybody has implementing their own protocol and that was creating lots of inefficiency. So relational database standardized the way we communicate with database. Then life moved on and everything was going well and suddenly, we entered into Big data scenario. Relational databases are unable to handle huge amount of data so the answer was “NoSQL”. So NoSQL was created because of limitations of relational databases.
     The data is structured in relational databases. We have to define table structure in advance, we have to tell the system in advance like table will have 10 rows and 10 columns and each column will take particular data type and this would be the maximum value one can enter and so on. This way we can't handle unstructured data where there is no fixed format or format is always changing. So NoSQL handles both structured and unstructured data.
-NoSQL focused to provide:
·         Scalability
·         Performance
·         High Availability
·         Simple API
·         Schema free
·         Ease replication support
·         Eventually consistent(not ACID)
      NoSQL can handle large amount of data.  As data is keep on growing it provides scalability and high availability in terms of hardware failure. Ability of NoSQL is to handle large amount of data with amazing performance with comparison they offers less functionality than RDBMS.

     NoSQL is category which can be commonly further divided into three categories given below with example:
·         Key Value Store : Memcached,Coherence, Redis
·         Tabular : BigTable,Hbase,Accumulo
·         Document oriented : Mango,CouchDB,Cloudant
If you search you will find more categories. Here is the list of some:
·         Column store/Column family
·         Document store
·         Key value store/Tuple sore
·         Graph database
·         Multimodel database
·         Object database
·         Grid and Cloud solution
·         XML database
·         Multidimensional database
·         Event sourcing
·         Network model
·         Other NoSQL related databases
·         Unsolved and uncategorized

      So what is missing from NoSQL databases if you compare them with relational databases? Well Joins are not there because of this joins relational databases are not so scalable. So in NoSQL databases this functionality is not implemented hence scalability and performance comes in. The support for complex transaction is not there for example you can’t not do insert tree records then update two records and check something if it’s not then rollback everything. Again constraint support is not there. Transaction support and constraint support is not there on database level but transaction support and constraint support can be applied on application level.

 What are the situations or scenarios where one can use NoSQL database?
·         The ability to store and retrieve great quantity of data is important.
·         Storing relationship between elements is not important.
·         Dealing with growing list of elements, example: Twitter post, Internet server logs, Blogs.
·         The data is not structured or the structure is changing with the time.
·          Prototype or fast application need to be developed
·         Constraints and validation logic is not required to be implemented in database.
What are the situations or scenarios where not to use NoSQL database?
·         Complex transactions need to be handled
·         Joins must be handled by databases
·         Validations must be handled by databases



Wednesday, August 6, 2014

How to change MAC address of smartphone mobile in Android

How to Change MAC address of Android Smartphone

Hello all readers, this post is related to changing MAC that is Media Access Control Address in smartphone, especially on Android. Well many people say it is not possible, but they are wrong it is actually possible and lets do it....

To do this activity, the Android smartphone must be rooted, that means you must have a Superuser enabled and if you don't know how to root then Google it with your smartphone name and download the root files.

Tuesday, July 22, 2014

Introduction to Hadoop

                    Hadoop is framework of Linux based set of tools. It is not any software that you can download on your computer and say "Hey, I have downloaded Hadoop". It is an open source tool and it is freely distributed under Apache license. It means no company is controlling Hadoop, It is maintain by Apache. The concept behind the Hadoop is big data.

Monday, July 21, 2014

Breakthrough – Converting your Partition from Primary to Logical

In the technological race of Computers, People and Programmers are obsessed with OS (Operating System). At the same time we are unable to loosen the love for our regular OS; since we are so much habitual to it, and we have a solution called DUAL-BOOTING. That’s where your partitioning comes into concern.

Most of the Desktops and Laptops now-a-days that you buy are partitioned as Primary. The Primary partition is mostly seen when you have bought a Windows OS installed machine. But in the craze for other OS you tend to take a risk, but that may be fatal to your system, since your data is on stake. The important part is when you have to dual-boot, that is you want to install another OS, you “should not install” it on “primary partition”, since it is just a partition visible to end user (you), internally it’s your whole Monolithic HDD!

Sunday, July 20, 2014

Problem Step Recorder (PSR) In Windows 7/8

          Problem Step Recorder (PSR) is an in-built step recorder provided in Windows 7 and Windows 8. It maintains a record of steps taken, while doing some sequence of actions on computer. Thus snapshots of screen are recorded in one file once the PSR is enabled. 

Friday, July 18, 2014

New Born Malware

My today's blog is about the newly born malware. Before getting to that newly born malware let me firstly tell you what is the malware.
Malware is malicious software, is any software used to disrupt computer operation, gather sensitive information, or gain access to private computer systems. It can appear in the form of executable code. 

Wednesday, July 16, 2014

How to switch on LED on board using Raspberry pi

Hello folks !
Welcome to raspy tutorial ...

This post is for switching a LED light using terminal in raspberry pi.

To do this activity you need to get Administrative rights first of all. So, type the following commands in your terminal.

$sudo su