Author: Michał Kołodziejski

Senior Software Engineer

How You Can Use Hibernate With a Database Modeling Tool

Before writing this article, I talked to a group of software engineers who use Hibernate on a daily basis in their work. Some of them work for small companies (up to 20 developers on site) while others are employed in corporations known world-wide that employ over 100,000 IT professionals. This gave me an insight into how development with Hibernate is organized in different companies.There are several approaches to creating SQL scripts and Hibernate O/R Mapping classes.

Dirty PostgreSQL Database? Clean It up With a VACUUM!

Just like your house gets dirty and requires cleaning from time to time, your PostgreSQL database may accumulate “dust” too. Unwanted pieces of data make the DB grow bigger and bigger. However, there is a mechanism to get rid of junk data and the DB can do it automatically for you.How Does a Database Get “Dirty”?Let’s talk a little bit about concurrency in databases. Generally, when multiple users (or more concretely – database transactions) read or modify the data stored in a database at the same time, they may conflict with each other. One user wants to read the row while another one may want to modify it. They do these operations within different transactions so they should be able to do their jobs without worrying about someone else doing something with the same data. It’s the DBMS’s job to handle it. So let’s look at this problem from a DBMS’s perspective. There are a few possible strategies to do this.

Chrome’s Monopoly Is Broken! Vertabelo Now Supports Safari

Yes, I know that’s a tabloid-style headline but I couldn’t resist. The day has finally come. Now, you can create your database models in the Safari browser. I think it’s a good time to say a few words about why we restrict access to Vertabelo from most browsers and why we let Safari in.Our lack of support for browsers other than Chrome has been one of the most commented topics since Vertabelo came online. There were

The Easiest ERD + ORM Integration Ever: Vertabelo and jOOQ

What is jOOQ? jOOQ, which stands for “jOOQ Object Oriented Querying,” is an ORM (object-relational mapping) for Java. With jOOQ you don’t write statements with “SQL-like language”; like Hibernate’s HQL. Instead, you write well designed and intuitive DSL code which, for someone speaking SQL, is obvious and self-explanatory. Read more » Some time ago I announced that the integration of Vertabelo and jOOQ was coming soon. While we’re waiting for an official (stable)

What Is a Database Index?

Sooner or later there comes a moment when database performance is no longer satisfactory. One of the very first things you should turn to when that happens is database indexing. This article will give you a general overview on what indexes are without digging into too much detail. We’ll discuss additional database index topics in future articles.In general, a database index is a data structure used to improve queries execution time. To explain what an index is, we need to say a few words on how the data stored in tables is organized.

Database Indexing – Whose Role Is It Anyway?

I remember my own confusion about who was responsible for database indexing when I was a junior programmer some years ago. At one of my very first commercial projects, software architects created a database structure, developers wrote the code, and browser magicians made it look outstanding. The final product was deployed to servers and champagne corks popped. Our good mood didn’t last for too long…After three months or so it turned out that one of the main features, a search engine, started choking. A rather simple search query took a few seconds to run. The time for optimization came very quickly. After some fast profiling with the production data and the cause of the slowdown became obvious – it was the DB that consumed too much time.

The Concept of Materialized Views (MVs)

The concept ofmaterialized views (MVs)is almost 15 years old; Oracle first introduced these views in the 8i version of its DBMS. However, some well known DB vendors (like MySQL) still don’t support MVs or have added this functionality only quite recently (it’s available in PostgreSQL since version 9.3, which was released just a year ago). In this article I’ll try to give you some tips about when you should use MVs in OLTP systems.

jOOQ – A Really Nice Alternative to Hibernate

In the Java world, there are many standards. Some of them have grown up from commonly used libraries or frameworks. For example, JPA, which was highly influenced by Hibernate.Standards are good. They eliminate chaos and bad practices. But standards shouldn’t be a kind of Bible for developers. A set of tools used in the project should be chosen consciously, not blindly “because it’s a standard and others use it.” It’s like in the business market, where a monopoly causes a lot more harm than good.

Vertabelo at 4Developers conference

Earlier this week, e-point SA (the company that develops Vertabelo) was a Partner at the 4Developers conference. I’d like to share some of my thoughts after meeting with many IT professionals who attended the event.About 4Developers4Developers is a conference for people connected with IT in many different ways. As stated on the conference website:“4Developers is a technical conference intended for developers, architects, testers, coders, team leaders, project managers, IT departments, as well as all IT students. The event is designed for both professionals and amateurs working in different technological fields. Above all, 4Developers is a platform - a meeting place for the tech community.”

SQL Performance Explained – the must-read book

Some time ago, the Vertabelo Team participated in the PostgreSQL Conference Europe 2013 . Some of the talks were really nice. One of them stuck in my head for quite a long time. It was Markus Winand’s lecture titled“Indexes: The neglected performance all-rounder.”Although I had had a solid background in databases, this 50 minutes long talk showed me that not everything concerning indexes was as clear to me as I had thought. This was the kind of lecture I like the most – when you sit and say to yourself “damn, I didn’t know that!”