How does PostgreSQL compare to “NoSQL”?
The term “NoSQL” covers such a diverse array of non-relational database implementations … from tiny embedded databases like TokyoCabinet to massive clustered data processing platforms like Hadoop … that it’s impossible to comment on them as a general class. Non-relational databases preceded relational databases and have existed alongside them for forty years, so choosing between relational and nonrelational databases is nothing new. Users should choose the database whose features, implementation, and community support their current application needs. Further, using multiple different databases for large projects is fast becoming the norm, and PostgreSQL users are no exception.