This is actually very easy because it works with openJDK that is included in openSUSE.
Get Oracle SQL Developer
Here it is, choose the “Oracle SQL Developer RPM for Linux”: http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html
By default openSUSE 12.1 will install only the Java Runtime Environment (JRE). SQL Developer needs the Java Development Environment (JDK).
su - zypper install java-1_6_0-openjdk-devel
Install Oracle SQL Developer
su - rpm --install sqldeveloper-3.1.07.42-1.noarch.rpm
When you run it for the first time, do it from the command line in Konsole, as a regular user. It will ask you for the location of the JDK. Input this: /usr/lib64/jvm/java
username@hostname:~> sqldeveloper Oracle SQL Developer Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. Type the full pathname of a J2SE installation (or Ctrl-C to quit), the path will be stored in ~/.sqldeveloper/jdk /usr/lib64/jvm/java