Do you remember the ? I promised you we'd explain how to design tables which have no update anomalies. Today we begin a series of posts on data normalization. We will talk about functional dependencies, a concept that needs to be explained before we dive deeply into database schema normalization.
The subject is rather abstract... Read more
In this article I will show you an example of the table that looks correct at first glance but when you try to modify data in it, several anomalies can occur. We'll discuss insert anomalies, update anomalies and delete anomalies. Read more
The kata This kata was inspired by a truly ugly piece of code we came across in Redgate Towers. It had a whole bouquet of code smells: long methods, a lot of indentation, static variables, inconsistent naming, code that was duplicated with small modifications, and a couple of small bugs. And, gloriously, it was... Read more
The kata You are given a program which is capable of traversing 2D mazes. However, the solution isn’t perfect and fails to find the exit in certain types of mazes. Moreover, the current solution is messy, doesn’t follow any sensible coding principles (e.g. SOLID) and is completely untested. The input to the program is... Read more
So you want to create your first database model but you don't know how to start? Read on!
I assume you already know a little about tables, columns, and relationships. If you don’t, watch our video tutorials before you continue. Read more
It's been already 100 days since we launched Vertabelo. There is already 1000 satisfied Vertabelo users. Thank you for your trust and interaction! Read more
In this third part of our Database Design 101 series you will learn about references – how to create a relationship between the tables, how it affects their structure, and how it looks in the data. Read more
The kata Imagine: it’s 1968 – the Beatles, Carnaby St and Austin Powers – except there’s all the technology of 2013 as well. Including vending machines. But, being 1968, vending machines have to deal with old money. It’s quite simple; I’ll describe it here. Money is made up of pounds (£), shillings (s) and... Read more
Sorry for that tabloid title, but I couldn't resist. I'm going to show you how to view the database design of other people’s systems. It will work for legacy systems as well. Of course, you may call show tables and describe table in the database console but that’s a very rudimentary way to examine the structure. You'll miss... Read more
In this video tutorial for beginners, you will learn about table columns and the most commonly used data types. Read more
