Well @barbarasmith , the article mentioned by @sandeep is clear enough I guess... What are you looking for exactly? Depending on that you can search for tech blog articles aimed to reach CIOs and managers, like this one for example: http://webcreek.com/2016/03/22/open-source-database-engines-mysql-vs-mongodb/ It's the tech blog of a web design company called Webcreek. The articles are serious but very easy to read. Take a look! Cheers!