NoSQL is going to replace the need of RDBMS completely.
MongoDB is going to get support of ACID compliance on multi-documents. While NoSQL out-weighs traditional RDBMS in terms of performance and scalability, ACID compliance on multi-document was a feature lacking in NoSQL and was long awaited.
As NoSQL will introduce ACID compliance on multi-document then there will be no reason left to run an RDBMS in parallel to No-SQL.
Based on premise above, we can foresee the technology shift from RDBMS (Relational Database Management System) to NoSQL.
On the other hand, NoSQL databases also provide advance features like memcache-compatible in-memory (RAM) cache with Skip-list and hash-table data structures to look up the data with sequential-keys. Couchbase also provides specialized Data Query Language like N1QL (dialect of SQL), MapReduce Programming (Views), and Fuzzy Search. It leverages scalability and reliability automatically and seamlessly through Nodes and Virtual-Buckets. This saves cost of explicit Database Clustering and Data Replication required in traditional RDBMS.
As NoSQL uses JSON data format therefore it will be wise for application architects to use a thin infrastructure layer of ODM over lightening fast NoSQL, instead of using a thick layer of ORM / Entity Framework on badly performing RDBMS.
RDBMS always come with their limitations due to storing BTrees on non-volatile Disks. BTrees have their own constraints specially when they grow large with ever expanding data volume.
In addition to performance, other benefits of using NoSQL is that JSON-based document can be integrated readily with Elastic Search, and other big data technologies like APACHE Hadoop.
Therefore, it is high time for the application architects to transform existing relational data to NoSQL in order to gain full benefit of Analytical Processing, MapReduce programming, Decision Support, Scalability, Reliability and high Performance.
Note: I would like to join Toptal Web Developers Network so as to implement the state-of-the-art solution-architectures by using advance technologies.
Article Written By: Fakhar Anwar Khan