Pythian Group

Among the features announced with the release of version 4.6 of the KDE Software Compilation is KateSQL, a SQL Query plugin for the Kate text editor providing the basic functionality of a SQL client. It leverages the Qt SQL module, allowing you to make a connection to most types of databases. Out of the box it includes support for MySQL and SQLite, and with this post I’ll show you how to get it to connect to Oracle databases as well.

Since I am an Ubuntu user (Note: you’ll need to be on 11.04 and either be running Kubuntu or have the ‘kate’ package installed) these instructions will be specific to that operating system, though they will likely also apply to other Debian-based distributions with minimal modification. However, if you are using an RPM-based distribution such as openSUSE or Fedora, you’ll need to adapt the instructions somewhat to make sure you have the necessary development packages installed.

The first thing we’ll need to do in order to get this to work is to obtain an Oracle client. This can be downloaded from the Oracle Technology Network and requires that you have a valid Oracle.com Single Sign-On account. For the purposes of this article we’re going to use the Linux x86 Oracle Instant Client and the files we’re going to download are:

oracle-instantclient11.2-basic-11.2.0.2.0.i386.rpm
oracle-instantclient11.2-devel-11.2.0.2.0.i386.rpm


The first package is the client itself, providing the files required to run OCI applications. The second is the Instant Client SDK which includes header files for developing Oracle applications with Instant Client: in our case an OCI library for the Qt SQL module.

Users of RPM-based distributions can just go ahead and install these packages while others will need to convert them to .deb format first. The best way to do this that I am aware of is with the tool called Alien. Let’s install it, convert the Oracle Instant Client packages, and install them too.

cd /path/to/oracle/instant/client/files
sudo apt-get install alien
sudo alien oracle-instantclient11.2-basic-11.2.0.2.0.i386.rpm
sudo alien oracle-instantclient11.2-devel-11.2.0.2.0.i386.rpm
sudo dpkg -i oracle-instantclient11.2-basic_11.2.0.2.0-2_i386.deb oracle-instantclient11.2-devel_11.2.0.2.0-2_i386.deb

The next step is to install all of the dependencies necessary to build the Qt SQL OCI library.

sudo apt-get build-dep qt4-x11
sudo apt-get install qt4-qmake libqt4-dev libaio1

Then we will need the actual source code for the qt4-x11 package. This can be obtained with the following command:

apt-get source qt4-x11

To recap, at this point we’ve downloaded and installed the Oracle Instant Client and all of the dependencies required to build the qt4-x11 package, and we’ve downloaded the qt4-x11 source code. Next we’re going to build the Qt SQL OCI library itself.

sudo ln -s /path/to/qt4-x11-4.7.0/src /usr/include/src
sudo cp -r /path/to/qt4-x11-4.7.0/include/QtSql/private /usr/include/qt4/QtSql/
cd /usr/include/src/plugins/sqldrivers/oci/
qmake "INCLUDEPATH+=/usr/include/oracle/11.2/client64" "LIBS+=-L/usr/lib/oracle/11.2/client64/lib -Wl,-rpath,/usr/lib/oracle/11.2/client64/lib -lclntsh -lnnz11" oci.pro
make
sudo make install

Now that the libqsqloci.so module has been built and installed, Kate should be able to connect to an Oracle database. Launch Kate (or close and re-open it if it was already running), click Settings -> Configure Kate, expand the Application tree if necessary, click Plugins, check ‘SQL Plugin‘ and click OK. Then click SQL -> Add connection to launch the connection wizard. In addition to the MySQL and SQLite database drivers, you should now also have drivers named QOCI and QOCI8 available. Choose the appropriate one, enter relevant connection details, and complete the connection wizard. You can now execute queries against the database and display result data.

For this blog I have compiled the main information specifically considering 11gR2 platform, but the concepts and idea also apply for older platforms as well.

Oracle provides the following JDBC drivers:

Read the rest of this entry . . .

Building High-Performance Drivers for Oracle Database 11g: OCI Tips and Tricks (PDF). I had the opportunity to have an early look at this white paper by Luxi Chidamdaram.

The paper goes over what needs to be done to use OCI effectively, especially in a web environment. The step-by-step approach taken in this document is very readable and the well explained code snippets make it a very good reference — great for comparing your code to the “proper” way to do it.

The novice OCI programmer will find the initial sections of great benefit, as it takes a lot of mystery out of OCI programming. For the more advanced OCI-head, the document is full of good examples of how to manage connections, sessions, and pooling–with an examination of what type of pooling is needed in a given situation.

One highlight for me was the section on database events, which are covered very effectively with some practical examples.

In short, this white paper is a must-read for both the OCI master and the novice, with some great pointers on how to use what is already in OCI and what is new in 11.