Friday 10 February 2012

NoSQL

I have hearing a lot about NoSQL these days. The first important thing to know about NoSQL is that NoSQL do not use SQL as the query language.  These data stores may not require fixed length table schemas. As the need to analyze unstructured data web data grows, NoSQL grows. With the rise of real time web, there is a need to analyze this huge amount of data. Companies realized that performance and real time nature was more important than consistency, which traditional databases were spending a lot of processing time to achieve. As such, NoSQL databases are highly optimized for retrieve and append operations and offer little functionality beyond record storage. The reduced run time flexibility compared to full SQL systems is compensated by significant gains in scalability and performance.

Traditional RDBMS are characterized by the transactional ACID properties of Atomicity, Consistency, Isolation and Durability. In contrast, NoSQL is characterized by BASE acronym :
1) Basically Available: It means we replicate the data among many different storage servers to make the failures partial.
2) Soft state: While the database which follows ACID properties make sure that the data is always in a consistent state, NoSQL allows data to be inconsistent. So, we need not refresh the database time and again since data can be inconsistent in a NoSQL database.
3) Eventually consistent: In contrast to ACID systems that enforce consistency at transaction commit, NoSQL guarantees consistency only at some undefined time in future. It means that data may not consistent at any given time, but it will eventually be consistent.

NoSQL emerged as companies struggled to deal with unprecedented data under tight latency constraints. This unstructured and semi-structured data provides a rich information source which can be harnessed to add more value to the business. Organizations which have massive data storage needs are looking forward to NoSQL. What the future holds for NoSQL remains to be seen.

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