Tuesday, June 26, 2012

Understanding NOSQL through Cassandra I

Though Cassandra has been having lot of attention these days, I was trying to get hold of some example which could be real eye opener who are very much accustomed with traditional SQL Type databases. I have tried to come across some fundamentals of NOSQL which I came across during this evaluation process of exploring Cassandra.

“Key value stores allow the application developer to store schema-less data. This data is usually consisting of a string which represents the key and the actual data which is considered to be the value in the "key - value" relationship

Key-Value Model:
Key-Value store is one of the key elements of non-relational database systems. Cassandra is based on Key-Value Model.

We can even say it as data store of key-value pairs. If you are familiar with programming constructs in languages such as Java, C# you will understand more on Key-value models. These programming languages use the key-value model with Hashtable, Map, Hash, etc.,

Example of key-value model can be given as below:

Name: Siva
Age: 32
Location: India

On the left hand side what you have is the key and on the right hand side what you have is the value. The combination becomes Key-value pair.

Keys: Name, Age, Location
Values: Siva, 32, India

In general terminology it’s called KVP (Key-Value Pairs). So it becomes easy to query the key and retrieve the respective value. This is the reason the distributed systems use this kind of mechanism for quick retrieval of data irrespective of the data type they handle.

We will see more in the next post.

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