Category: Databases

PingFIN X @ MCAST, Malta

For the fifth consecutive year MCAST IICT has hosted PingFIN, an International e-Payments Workshop organised by Odisee and currently in its tenth iteration. Also, co-hosting this event, in their respective campuses were Colchester Institute, UK and Fachhochshule FH Salzburg, Austria.

This event has become a staple in MCAST’s calendar and interest by our sponsors is growing, which this year included MITA, eSkills Foundation Malta, Microsoft Innovation Centre Malta, ccBill EU Ltd and RS2 Software PLC.

This year we had the highest attendance yet, with 24 local students and 15 visiting students and thus the change of venue. During the four day event from the 1st to the 4th of April all students were split into groups to work on the SEPA Credit Transfer and SEPA Recall Process using Oracle PL/SQL.

It most definitely was a unique experience for our participants working as a team, networking and learning new skills, whilst also getting feedback from professionals among our sponsors.

This was an unforgettable experience and I look forward for next year. I thank our sponsors, Kevin Picalausa from Odisee, all staff from MCAST for making this possible. Special thanks to my team: Alan Gatt, Daren Scerri, Luke Vella Critien and Robert Abela for their invaluable support. Finally and most of all, thanks to the students for taking our offer and making this experience special.

PingFIN 9 @ Malta

Glad to announce that all is set for the PingFIN 9 workshop. This is an international e-payments workshop being organised from Monday 12th-Thursday 15th March concurrently in 5 Universities Colchester Institute, Faculty of Organization and Informatics, FH SalzburgOdisee, Westerdals, and obviously MCAST. The workshop in Malta shall be held at the MITA Innovation Hub, SmartCity and it will be attended by 16 local and 12 foreign students.

This activity is being sponsored by MITA, MITA Innovation Hub, eSkills Malta Foundation and RS2 Software plc. Assisting me are my colleagues Alan GattLuke Vella Critien and Robert Abela. Visit our facebook page for more information.

Common Oracle XE and Oracle SQL Developer problems

Common Oracle XE and Oracle SQL Developer problems

SQL Developer – Connections tab not visible
1) Do make sure that you have downloaded the version that includes the jre
2) Do make sure that you have the right version, there is a 64-bit version if you have a 64-bit system.
3) Do make sure that SetJavaHome has been properly set to the Java location on your system, the option is found in the SQL Developer configuration file \sqldeveloper\bin\sqldeveloper.conf (http://forums.oracle.com/forums/thread.jspa?threadID=1049872)

Oracle XE Home Page returns Error 404
If you are using NetBeans or Visual Studio and your web pages or Oracle XE Home page are returning a Error 404: Page Not Found you might want to try the following link: http://hubpages.com/hub/ASPNET-DEVELOPMENT-SERVER–WEB-PAGE-CANNOT-BE-DISPLAYED

Unknown Locale
If when attempting to connect you are getting a Locale not recognized error, make sure that your regional settings are set to English, Control Panel->Regional and Language Options, you also need to add the following to the sqldeveloper.conf file: AddVMOption -Duser.Xlanguage=en
AddVMOption -Duser.region=US
(http://forums.oracle.com/forums/thread.jspa?threadID=369603)

Access Denied error when starting Oracle Database
If you are getting an Access Denied error when starting the Oracle XE server you need to right-click on the “Start Dabatase” option and select “Run as administrator”.

Other Errors
It is know that some errors are particular to Windows Vista, if you still cannot get either Oracle XE or Oracle SQL Developer to work you might want to try to install a Virtual Machine, install an OS of your choice (recommended Windows XP) and install Oracle XE then Oracle SQL Developer.

Complete Un-installation of PostgreSQL from Mac OS X Lion

Complete Un-installation of PostgreSQL from Mac OS X Lion

In response to a question on stackoverflow, here is a short guide on how to completely uninstall PostgreSQL 9.1 from Mac OS X Lion.

  1. Open a terminal window

    Utilities->Terminal

  2. Run the uninstaller

    sudo /Library/PostgreSQL/9.1/uninstall-postgresql.app/Contents/MacOS/installbuilder.sh

    PostgreSQL Uninstall Wizard

    PostgreSQL Uninstall Wizard in Progress

    Data not removed after PostgreSQL Uninstallation
  3. Remove the PostgreSQL and data folders (Wizard will notify you that these were not removed)

    sudo rm -rf /Library/PostgreSQL

  4. Remove the ini file

    sudo rm /etc/postgres-reg.ini

  5. Remove the PostgreSQL user

    System Preferences -> Users & Groups

    Unlock the settings panel by clicking on the padlock and enter your password

    Select the PostgreSQL user and click on the minus button.

Remove PostgreSQL User

 

Configuring MySQL Workbench with MAMP on Mac OS X Lion

Configuring MySQL Workbench with MAMP on Mac OS X Lion

Installing MAMP on Mac OS X Lion is surely an easy way of getting Apache, PHP and MySQL working on your system. If you plan on using MySQL Workbench you will need to do some additional steps.

  1. Create the missing my.cnf file.
    1. Open a terminal window.
    2. Create the file by typing:
      sudo touch /etc/my.cnf
    3. Change the owner of the file to your username:
      sudo chown fraki /etc/my.cnf
  2. Create a new server instance and shown in my previous post: MAMP, MySQL Workbench and WordPress setup guide
  3. Edit the server instance settings as follows:
    1. Set the MySQL Server start command to:
      /Applications/MAMP/bin/startMysql.sh
    2. Set the MySQL Server stop command to:
      /Applications/MAMP/bin/startMysql.sh
    3. Set the MySQL Server status command to:
      ps xa | grep “/Applications/MAMP/Library/bin/[m]ysqld”
Configuring MySQL Workbench on OS X Lion with MAMP

Keep checking through the guide for additional configuration.

Subtypes or Roles for parties

Recently I participated in a discussion of a common problem in data modelling. The question is whether to represent parties (groups) as roles or as subtypes (generalisation hierarchy).

When designing the Conceptual Data Model, parties can be represented as subtypes provided there is a common context amongst sub-types. In the Logical Model, subtypes should be represented only if each subtype has a unique concept that the others don’t.

You can read view the LinkedIn discussion here and/or see my Short notes on Barker’s ERD Notation.

MAMP, MySQL Workbench, WordPress installation and setup guide for MAC

MAMP, MySQL Workbench, WordPress installation and setup guide for MAC

Another task that I needed to do after buying my Mac was to get my Web toolkit working. Apache, MySQL and PHP are very conveniently managed by MAMP, WordPress is as straight forward as always. MySQL Workbench required some fine tuning but managed to fix it properly.

 

Decided to document everything as I went along and prepared a well documented guide with some of my personal recommendations. Hope you will find it useful and as always all feedback is welcome.

 

MAMP, MySQL Workbench and WordPress setup guide

 

ERD Modelling using Barker’s Notation

ERD Modelling using Barker’s Notation

A key process in database development is obviously database modelling and the main diagrams used are ERD. A number of notations exist, some particular to evangelised by particular DBMS. Here I am documenting a short course/notes about ERD modelling using the Barker’s notation, which is greatly adopted by Oracle.

As usual here is the link, do feel free to comment!

Short notes on Barker’s ERD Notation

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