When should I use a NoSQL database instead of a relational database? Is it okay to use both on the same site?

Question

What are the advantages of using NoSQL databases? I\'ve read a lot about them lately, but I\'m still unsure why I would want to implement one, and under what circumstances I

Answer 1

Relational databases enforces ACID. So, you will have schema based transaction oriented data stores. It's proven and suitable for 99% of the real world applications. You can practically do anything with relational databases.

But, there are limitations on speed and scaling when it comes to massive high availability data stores. For example, Google and Amazon have terabytes of data stored in big data centers. Querying and inserting is not performant in these scenarios because of the blocking/schema/transaction nature of the RDBMs. That's the reason they have implemented their own databases (actually, key-value stores) for massive performance gain and scalability.

NoSQL databases have been around for a long time - just the term is new. Some examples are graph, object, column, XML and document databases.

For your 2nd question: Is it okay to use both on the same site?

Why not? Both serves different purposes right?