Databases
A database is nothing more than a collection of data, usually organized in some structured way. We use databases everyday although we might not think of them as databases. Take a phone directory, for instance. It contains a lot of data. The data itself consists of names, addresses, and, of course, phone numbers, typically sorted by last name. This paper database has many disadvantages, though. Once it is printed, it will be incomplete and out of date. And if we want to look up the phone numbers of all the people that live in the same street, we would not know where to start. But it is a database, alright.
Relational databases
The term relational databases dates back to an article written in 1970 by Edgar Frank Codd, working at IBM at the time, called A Relational Model of Data for Large Shared Data Banks.
It presents a model that shows the relationships between the different elements of data and heavily uses tables. In each of those tables, there are several fields or columns that...
