A brief history of databases
Relational databases have been around for over 50 years. The first database was created by Edgar F. Codd in 1970. The main feature of a relational database is that data is arranged in rows and columns, and rows in tables are associated with other rows in other tables by using the column values in each row as relationship keys. Another important feature of relational databases is that they normally use Structured Query Language (SQL) to access, insert, update, and delete records. SQL was created by IBM researchers Raymond Boyce and Donald Chamberlin in the 1970s. Relational databases and SQL have served us well for decades.
With the increase in the popularity of the internet in the 1990s, we started hitting scalability limits with relational databases. Additionally, a larger variety of data types started cropping up. RDBMSes were simply not enough anymore. This led to the development of new designs. And with this, we got the fuzzy and confusing term...