Author: Adrian Więch

Technical Writer at Vertabelo.

Vertabelo XML Version 2.3

The XML file format for Vertabelo has changed to version 2.3. Read this article to find out what is new. Vertabelo keeps its models in XML format; if you need, you can download the files and extract information from them. Previously, we used XML version 2.1, as discussed in this article. We’ve switched to XML 2.3, and a couple of changes took place. These changes make no difference for most Vertabelo users.

How to Embed Your Database Model Into a Website

Did you know that you can embed your database model in your website? If you haven’t tried this yet, now’s your chance – we’ve recently improved the process. It’s an excellent way to share ideas with readers or make projects available to co-workers. You might have already seen some interactive models embedded in our blog. They look like this: if (typeof VertabeloEmbededObject === 'undefined') {var VertabeloEmbededObject = "loading";var s=document.createElement("script");s.setAttribute("type","text/javascript");s.setAttribute("src", "

Problem Set 2 – Identifying Entities and Attributes

function toggleDiv(id) { $("#hide-show-div-" + id).toggle(); var button = $("#hide-show-button-" + id); var label = button.prop('value'); if (label == 'Hide Solution') { button.prop("value", "Show Solution"); } else { button.prop("value", "Hide Solution"); } } In an earlier article on data modeling we promised to give you a set of exercises to practice finding entities and attributes. Here is the second installment of our problem set. Enjoy. Problem 1: Countries Description: Find the right entities and their attributes to represent all the countries in the world, their interior regions (which can be called states, provinces, or regions) and their cities.

Problem Set 1 – Identifying Entities

function toggleDiv(id) { $("#hide-show-div-" + id).toggle(); var button = $("#hide-show-button-" + id); var label = button.prop('value'); if (label == 'Hide Solution') { button.prop("value", "Show Solution"); } else { button.prop("value", "Hide Solution"); } } In an earlier article on data modeling we promised to give you a set of exercises to practice finding entities. Well, here they are. Have fun! Problem 1: Language School Mr. Trotter, the proprietor of a rapidly-growing language school, wants to introduce a new system in his company.

Database Modeling Course (2)

You’re finally ready to get down to real data modeling. We’ll start off with entities and their attributes. Entities are the basic building block of every data model. In this post, you’ll find out what they are and how to identify them. What Is an Entity? What is a Specific Instance of an Entity? Data models help us to identify what kind of information we’ll store in our system. We use such models to address the question What will the data in our system be about?

Interesting Changes in MySQL 5.7

The General Availability version of MySQL is still version 5.6, but the development release of MySQL 5.7 definitely introduces some exciting changes to the world of database management systems. Is it worth giving a try? In this article, we’ll have a closer look at a few brand-new features that may help you decide to do so. Native JSON Support JSON (short for Java Script Object Notation) is a format for storing information which can be a good alternative to XML.

Database Modeling Course (1)

Data modeling is an essential step in the process of creating any complex software. It helps developers understand the domain and organize their work accordingly. In this article, which begins a new series devoted to database modeling, we’ll try to convince you why you should include it in your projects and what it looks like. Do I Really Need Data Modeling? As a novice developer, you often start your programming adventure with simple applications like the sieve of Eratosthenes or enumerating the Fibonacci sequence.

Understanding Execution Plans in PostgreSQL

Execution plans can become a very useful tool for every database developer. They provide a deeper understanding of the mechanisms applied in the processing of queries. This article will take a closer look at how execution plans are retrieved and how to read them. What Are Execution Plans? SQL is, to a great extent, a declarative language. The user defines what should be done but does not specify how the queries should be executed.

Sequences in Database Systems

Generating unique integers is a very common task in database systems. Many applications require each row in a given table to hold a unique value. One way to tackle this problem is to use sequences. What are Sequences? A sequence is a database object which allows users to generate unique integer values. The sequence is incremented every time a sequence number is generated. The incrementation occurs even if the transaction rolls back, which may result in gaps between numbers.