Allgemein

Create an ER Diagram of an Existing SQLite Database (or many other RDBMS)

Visualisation helps solving problems and is therefore an important tool database design. Many database providers have their product specific tools for re-engineering existing schemata, but self-contained, serverless, embedded relational database management systems(RDBMS) such as SQLiteoften come without much tooling support. The extremely small footprint of SQLiteprovides a very powerful tool for implementing database driven applications without the hassle of database administration, user privilege management and other demanding tasks that come with more complex systems.

Importing your Repositories from Github to your Gitlab Instance

Github is a great service and offers a free micro accountfor students, which includes five private repositories. Still this might not be enough private repositories for some of us, especially if you start a lot of side projects (which are hardly finished :-)) and want to keep your code and data organised, versioned and collaborative but non-public (because it is not finished yet :-)). For this and other reasons I am also running a private Gitlabinstance, which basically offers the same features as Github and can be hosted on your private server.

A quick fix for the ‘ascii’ codec can’t encode character error in Python and the csvkit tool

For a current project I need to migrate large volumes of CSV data into a relational database management system. The Python driven csvkit is the swiss army knifeof CSV tools and very handyfor this purpose. However, a few CSV files cause troubles when I tried to pipe the SQL CREATE statements I created with the csvkit tool to a file. csvsql -i sqlite -d ';' -e 'utf8' --db-schema test_schema --table test_table inputfile.

Den UPC Wireless Cable Router durch den eigenen WLAN-Router ersetzen

Nachdem das Netzteil meines UPC Modems das zeitliche gesegnet hat, pilgerte ich zum UPC Store am Keplerplatz und ließ das gesamte Gerät tauschen. Der Austausch erfolgte unkompliziert, doch leider hatte ich anstelle des althergebrachten Modems nun endgültig einen Wifi-Router erhalten, wogegen ich mich bisher immer gesträubt hatte. Schließlich betreibe ich einen liebevoll eingerichteten Netgear WNR 3500L mit der altenativen Firmware TomatoUSB und hätte keine Lust, mein Setup auf dem UPC Gerät umzusetzen und auf Funktionen zu verzichten.

Migrating Markup Languages

There exists a broad range of different markup languages, which allow you to structure, highlight and format your documents nicely. Different wiki platforms utilise various markup languages for rendering texts, Github and other code sharing platforms use their own dedicated languages for their documentation files. These markup languages such as Textile or Markdown work rather similar, as they provide users with a basic set formats and structural elements for text. In order to avoid vendor lock-in or when you need to move to a different system, you will need to extract the information from the old markup and make it available in a different language.

Blattlinien in überregionalen Tages- und Wochenzeitungen

Österreich verfügt über ein überschaubaren Zeitungsmarkt, dem es insbesondere an überregionalen Qualitätserzeugnissen mangelt. Trotz einiger weniger Lichtblicke, beherrscht das Kleinformat den Markt und damit zu weiten Teilen die öffentliche Meinung. Um dem Zeitungssterben entgegenzuwirken, bieten die meisten Tages- und Wochenzeitungen zusätzlich ein Online-Portal an. Das Österreichische Mediengesetz sieht in periodisch erscheinenden Medien eine sogenannte Offenlegung (§25) vor, in der nicht nur die Eigentumsverhältnisse der Medien, sondern auch eine Erklärung über die grundlegende Richtung eines periodischen Druckwerks anzugeben ist.

Die dritte Auflage des MySQL Handbuchs

Nachdem wir im Dezember erfahren hatten, dass sich die Bestände der zweiten Auflage zu Ende neigen, ging es für uns Autoren an die Planung der dritten, aktualisierten Auflage des MySQL Buchs. Von Jänner bis April 2015 haben Eva Zangerle, Wolfgang Gasslerund ichan der Neuauflage unseres Buches gearbeitet. Eva, Wolfgang und ich haben seitenweise Release-Notes durchgeackert, Leser-feedback und wünsche eingearbeitet und natürlich so gut wie alle neuen Features berücksichtigt. Selbstverständlich haben wir auch das Datenset komplett neu erzeugt und mit Millionen von Einträgen gefüttert.

Persist Web Radio Streams in the Pi MusicBox

After upgrading my Raspberry Pi Model B to the new Raspberry Pi 2 a few weeks a go, I finally found a new purpose for the old device. There exist several images for the Pi with a focus on with Internet radio streaming. After doing a little research, I decided to use the Pi MusicBox, which comes with a headless audio player and supports a whole lot of different sources and formats: Spotify, SoundCloud, Google Music, Podcasts (with iTunes, gPodder directories), local and networked music files (MP3/OGG/FLAC/AAC), Webradio (with TuneIn, Dirble, AudioAddict, Soma FM directories), Subsonic.

Debugging Thunderbird Problems with Linux

Sometimes it can be hard to reproduce problems related to Email as many factors can be a cause for the trouble. Thunderbird (and all other Mozilla products) provide logging facilities which allow tracing the activities of the application and to detect the source of an error. The logging mechanism is activated by setting two environment variables as described in the documentation. The following two lines will set the environment export NSPR_LOG_MODULES=imap:2,smpt:3,timestamp export NSPR_LOG_FILE=/tmp/mail.

Using Twitter to get the current IP address of your Raspberry Pi

The Raspbery Pican act as a rather neat server due to its low power consumption and its flexibility. As it is very small and can be powered with a standard dell phone charger, its convenient to take it with you. But running in headless mode (i.e. no monitor is attached) and without a keyboard connected it can be a pain to “find” the device in a network as it receives a dynamic IP address whenever it gets connected via ethernet or wifi.

Use a TP-Link TL-WR710N Router as a Repeater with OpenWRT

The TL-WR710N offers five modes of operation: Router mode Client mode (connects ethernet devices to an existing wifi) Repeater mode (extends existing wifis) Access point mode (create a wifi hotspot from a wired connection) WISP Client Unfortunately the firmware which is installed on the device is very instable and barely usable for my purpose. I could not get connectivity by using the software which is pre-installed although it would offer a nice interface for all the mentioned modes.

Configuring a catch-all VirtualHost for Apache2

Recently I noticed an interesting behavior of my Apache2 setup when I introduced a new VirtualHost and enabled the site. Usually I store the configuration for each host in an individual file, because it is much easier to maintain. The main page that I serve is this WordPress blog, having the ServerName blog.stefanproell.at and several aliases. The configuration files have the same name as the ServerName of the VirtualHost they configure.

Hauling Servers

After more than four years running my Web applications on Server4You infrastructure, I decided to move on. The reason for my decision to look for a new provider was the decreasing performance of my Server4You Pro X4 Server, especially in comparison with contemporary offers of other vServer providers. I therefore moved this blog and other PHP based applications to a DigitalOcean droplet, which offers 20 GB SSD storage, 512MB RAM and full root access for only 5$ per month.

MySQL 5.6 – Die zweite Auflage des Handbuchs für Administratoren

Fanfare, Freude, Feuerwerk! Vor wenigen Tagen ist die zweite Auflage unseres MySQL Administrationshandbuchs erschienen. Eva Zangerle, Wolfgang Gassler und ich haben uns in den letzten Monaten wieder an die Arbeit gemacht und alle wichtigen und vielschichtigen Neuerungen der Version 5.6 von MySQL in eine neue Auflage eingearbeitet. Vor zwei Jahren ist die erste Version dieses Buchs erschienen. Wir haben tolles Feedback bekommen, mit Lesern diskutiert und dabei selbst sehr viel gelernt.

MySQL – Das Handbuch für Administratoren

Seit kurzem gibt es ein neues Buch im Portfolio von Galileo Computing: MySQL – Das Handbuch für Administratoren. Dieses Buch ist für mich etwas ganz besonders, nicht nur, weil es das erfolgreichste Open Source Datenbankmanagementsystem der Welt zum Inhalt hat, sondern weil es sich dabei um den erfolgreichen Abschluss eines sehr spannenden und komplexen Projektes handelt. Gemeinsam mit Eva Zangerle und Wolfgang Gassler habe ich in den letzten Monaten so gut wie jede freie Minute für dieses Buch aufgewendet und seit wenigen Wochen ist es nun veröffentlicht worden.

Microsoft Office 2007 and Ubuntu

You really need Microsoft Office for work but you are not willing to switch to a Microsoft brand operating system? No problem! Office 2007 works like charm with the windows compatible runtime environment Wine. Just follow thistutorial and you can start using MS office, which is still not completely replaceable by open source software, especially if you have to exchange documents with other people using it. For the record: I still prefer Latex, but sometimes one has to bite the bullet, which is actually not that much of a problem.

How to setup a MIDI-Keyboard in Ubuntu

I finally got myself a small (actually, it’s tiny) MIDI-Masterkeyboard for “tinkling the ivories”, which is a wonderful passion for lazy afternoons. Isn’t it cute: I decided to get an Akai LPK 25, which doesn’t use much space, is cheap and quite sufficient for my purposes. In order to use it with Linux, one has to follow a few steps in order to get some sound out of that instrument.

Ubuntu Update from 9.04 ( Jaunty Jackalope ) to 9.10 ( Karmic Koala )

I finally took the courage of updating to the latest Ubuntu release on my PCs and notebooks. Major upgrades always bear a risk of incompatibilities of installed components. So I decided to wait one month after the new version of Ubuntu was released, in order to wait for possible problems to be solved by the developing team meanwhile. Long story short: Core2Duo custom PC: like charm Sony Vaio VGN-F221E (work): no problems, except Exim4 denied to work out of the box and Firefox has some display errors Samsung NC10 Netbook: Ubuntu Netbook Remix.

Huawei E156G USB Stick on Ubuntu 8.10 (Intrepid Ibex)

Surprisingly (or not), the UMTS modem E156G by Huawei works out of the box with the new version of the network-manager, which is shipped with the current release of Ubuntu 8.10. Once the USB modem is plugged in, the system recognizes it corretly and even offers a list of providers. One click on „Drei“ got me online. Nice!

Huawei E156G USB Stick on Ubuntu 8.04

Today I got myself mobile internet for my notebook, as I am going move to Vienna and do not want to spend a single day without having a working Internet connection available. The cheapest offer I could find for my purpose was the 3Data Lässig rate (15 GB for 16€ per month). As I am extremely impatient, when it comes down to buying electronics, I headed for the telecommunications store in my home town and registered for the mentioned 3Data rate, which came with a Huawei E156G stick.