Oracle – Frankie Inguanez

Tag: Oracle

Common Oracle XE and Oracle SQL Developer problems

Posted on 2012-02-12 by Frankie

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.

Subtypes or Roles for parties

Posted on 2012-02-10 by Frankie

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.

ERD Modelling using Barker’s Notation

Posted on 2012-01-16 by Frankie

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

SQL for not registering employees for conflicting appointments!

Posted on 2011-12-14 by Frankie

I was once asked by a fellow colleague if it was possible to have an SQL statement that would not allow employees from being registered to events that occur simultaneously.

Scenario

Consider a database that stores a list of persons and a list of events. Employees would eventually be registered as event attendees. It is possible that multiple events occur at the same time and therefore it is required that the SQL statement prevent any persons from being registered as attendees of conflicting events. It was required that the solution be all in one SQL statement for some reason whatsoever.

The SQL solution is found attached together with a supporting report! As always all feedback and queries are welcome!

Oracle DBMS 11g Release 2

Posted on 2011-12-12 by Frankie

Out of sheer curiosity I had decided at the beginning of the year not to satisfy myself with Oracle Express Edition and started experimenting with Oracle 11g Release 2. It wasn’t long before I got it up and running on Windows systems and was able to administer it with ease thanks to the ample documentation found. The same can be said for installation on Red Hat Linux which is officially supported by Oracle. Being a little bit curious I wanted to test it on my two favorite operating systems, CentOS and Ubuntu.

Well it wasn’t all that easy and there isn’t much documentation for those OSs. I spent a lot of time reading various postings then testing and experimenting myself, documenting all along the way. Finally I managed to get Oracle working for CentOS 5.5, Ubuntu 10.10 and Ubuntu 11.04 with good documentation. This will be a continuous work in progress and will plan to keep updating it.

Today I found some time to fix the presentation of the document and decided that it is fine time to share it with the public. So here is the link in the way that I would have loved to have found it on the net: Oracle 11g R2 Guide

As usual all feedback is more than welcome!

Oracle Express Edition 11g R2

Posted on 2011-12-12 by Frankie

One of my subject areas is information systems, and the undisputed number one brand in database systems is obviously Oracle. Recently Oracle have improved their light version of their flagship product the Oracle Express Edition and have also updated SQL Developer. I had prepared an installation guide for both software which I have updated for public use!

If it interests you here is the link: Oracle Express Edition 11g Release 2 and Oracle SQL Developer

Do leave some feedback for this guide!