NoSQL started off in 2006-2007 as an edgy, against-the-mainstream name, a counterpoint to the complete dependence on the SQL access language that relational database systems had at the time.
The pioneers of NoSQL systems never said it was their goal to replace SQL systems, which have been the foundation of venerable relational databases for the last 30 years, such as Oracle, DB2, and PostgreSQL. Rather, NoSQL developers wanted to be freed from the restrictions and preoccupation with precision that marked SQL systems. They were driven by the new demands the Internet was placing on how databases operated in the real world.
Here are the key differences between SQL and NoSQL systems:
Where SQL relational databases were concerned only with data integrity, NoSQL is concerned with data immediacy and relevancy.
Where a SQL relational system employs the unforgiving ACID test, NoSQL invokes "eventual consistency."
Where a SQL system dictates a particular data type, NoSQL allows a loosey-goosey tolerance of many data types -- and still comes up with workable intelligence.
Instead of precision with defined schemas, NoSQL pioneers sought an ability to handle information at high volume and high speed. Instead of getting one transaction exactly right, they wanted to deal with a million users at once. View more