Use an object in a query?

Using an Oracle object type’s instance in a query is a powerful capability. Unfortunately, Oracle’s SQL syntax doesn’t make it immediately obvious how to do it. Most get far enough to put it in a runtime view (a subquery in the from clause), but then they get errors like this:

SELECT	 instance.get_type()
         *
ERROR AT line 4:
ORA-00904: "INSTANCE"."GET_TYPE": invalid identifier

The problem is how Oracle treats (more...)

ORDER BY CASE

Sometimes I give parts of a solution to increase the play time to solve a problem. I didn’t anticipate a problem when showing how to perform a sort operation with a CASE statement. It’s a sweet solution when you need to sort something differently than a traditional ascending or descending sort.

I gave my students this ORDER BY clause as an example:

  CASE
    WHEN filter = 'Debit' THEN 1
    WHEN filter = 'Credit' THEN 2
     (more...)

Mac SQL Developer Install

This how you install SQL Developer on Mac OS Yosemite. The first thing you need to do is download and install Java 8, not Java 7 on your Mac OS Yosemite, as suggested on some web sites. You can determine whether or not Java is installed by running the following command:

Mac-Pro-3:~ username$ java -version
No Java runtime present, requesting install.

You must accept the Java license to install Java 8 on the (more...)

Run X11 Apps on Mac

It’s possible folks didn’t notice but Mac OS X no longer includes XQuartz by default from Maverick forward. You need to download XQuartz and install it. I’d recommend after you install Xcode.

Launch XQuartz and then either use the bash shell it opens or open a Terminal bash shell session. Inside the shell, you might start Secure Shell (ssh) like this:

Mac-Pro-3:~ michaelmclaughlin$ ssh student@192.168.2.170
student@192.168.2.170's password: 
 (more...)

Fedora X11 Install

While working through getting my Mac OS X to work with X11, I stumbled on some interesting errors and misdirection solutions. Like most things, the solution was straightforward. Then, it struck me that I hadn’t installed it on my Fedora image. This blog post show you the errors I got the way to get it to work, and how to install X11 on Fedora.

The first step requires discovering the package. If you remember xclock (more...)

Bash Arrays & Oracle

Last week, I wrote about how to use bash arrays and the MySQL database to create unit and integration test scripts. While the MySQL example was nice for some users, there were some others who wanted me to show how to write bash shell scripts for Oracle unit and integration testing. That’s what this blog post does.

If you don’t know much about bash shell, you should start with the prior post to learn about (more...)

Bash Arrays & MySQL

Student questions are always interesting! They get me to think and to write. The question this time is: “How do I write a Bash Shell script to process multiple MySQL script files?” This post builds the following model (courtesy of Download MySQL Workbench) by using a bash shell script and MySQL script files, but there’s a disclaimer on this post. It shows both insecure and secure approaches and you should avoid the insecure (more...)

Add Gedit Plugins

Fedora comes with vim and gedit installed but the gedit installation is bare bones. You can update gedit to include supplemental Plug-ins with the following yum command as the root user:

yum install -y gedit-plugins

It generates the following log file:

Loaded plugins: langpacks, refresh-packagekit
mysql-connectors-community                                  | 2.5 kB  00:00     
mysql-tools-community                                       | 2.5 kB  00:00     
mysql56-community                                           | 2.5 kB  00:00     
pgdg93                                                      | 3.6 kB  00:00     
updates/20/x86_64/metalink                                  |  14 kB  00:00     
updates                                                      (more...)

Eclipse on Fedora

While I previously blogged about installing Netbeans 8, some of my students would prefer to use the Eclipse IDE. This post shows how to install and configure Eclipse IDE, include the mysql-connector-java.jar, and write Java to access the MySQL.

You can download Eclipse IDE and then open it in Fedora’s Archive Manager. You can use the Archive Manager to Extract the Eclipse IDE to a directory of your choice. I opted to extract (more...)

C Shared Libraries

I wrote a shared C library example to demonstrate external procedures in the Oracle Database 11g PL/SQL Programming book. I also reused the same example to demonstrate Oracle’s external procedures in the Oracle Database 12c PL/SQL Advanced Programming Techniques book last year. The example uses a C Shared Library but a PL/SQL wrapper and PL/SQL test case.

One of my students asked me to simplify the unit test case example by writing the (more...)