It's not necessary to work on a big project to use SVN. Keeping your design into SVN repository is very useful and good practice. By doing so you could easily see what changes you've made to the design and in case of accident you could restore any older version and correct the problem.
After you successfully setup Subversion (here) it's time to start integrating tools with SVN. Integration of Oracle SQL Data Modeler is really easy and it's done in few simple steps:
Integrated Oracle SQL Data Modeler with SVN:
Start Oracle SQL Data Modeler
Go to View -> Team -> Versioning Navigator
At the Versioning Navigator window, right click on Subversion and then New Repository Connection.
Populate the fileds at new window Create Subversion Connection with repository URL, username, password and name for the repository.
Import files to the repository:
Once configured you have to import all the files on which you are working, including the database design to the repository. For this purpose you could use Data Modeler itself, but I prefer TortoiseSVN to create the repository structure and then import all the files in it. As I mention in preventions post, the best practice is to create three directories trunk, branch and tags and then import your working directories to trunk.
When these files are imported you should delete them from your hard drive and checkout the same files from the repository so you have a working copy.
- Start using Oracle SQL Data Modeler and SVN:
Checking out from the repository could be done by TortoiseSVN or by Oracle SQL Data Modeler -> Versioning menu -> Checkout. Once you have a working copy you could open the design and start working on it.
Next time you make a change and save the design you'll be able to commit these changes to the repository, again by going to Versioning menu and then Commit. Using comments is also good idea so you could easily track when and what changes you've made to the design.