You’ve probably heard the word Oracle mentioned in discussions about databases, but you possibly do not know that Oracle is a corporation. It makes software to create and manage databases – so-called Database Management Systems. That’s the DBMS acronym from way back in paragraph 1; and an RDBMS is, of course, a Relational Database Management System.
Oracle began making RDBMS in the 70s. Today, the Oracle database is, by most metrics, the most popular in the world (it does have some strong competition; we’ll talk about them later. This isn’t like football; now you’re part of Team Oracle, it doesn’t mean you have to hate the opposition. Not much, at least). The latest version of the database is Oracle 12c. You don’t particularly need to remember that now – in fact, you don’t particularly need to remember anything from this section. We’re just painting in the background; the juicy stuff is what comes next.
It’s time to roll up our sleeves and get our hands dirty. Go get your address book again.
Remember I’d said the data in databases is organised in groups – all the names over here, the phone numbers over there, the addresses over in that other place? Well, those groupings are called tables.
So in our little database we have a FRIEND_NAME table, a PHONE_NUMBER table, and an ADDRESS table. Got that? Cool.
Tables are made up of vertical columns and horizontal rows. The columns contain data of the same type; while rows contain the data that makes up an item. In our example FRIEND_NAME table, the Last_Name column contains all the surnames – Geller, Bing, Tribiani, Geller-Bing, Green and Buffay – while the rows contain the full names, such as Ross Geller.