here is a book on Subversion Version Control with Subversion
1) you check out once into local working copy (WC) and after that you can change, commit and update that working copy - through pending changes, no need of another check out
2) WC keeps last synchronized status, so you can compare against it or revert to it without need to be connected to SVN repository
3) Lock is just a flag telling to other users that you want to work exclusively on that resource - that doesn't mean someone else cannot steal the lock; In our daily work we do not use locking - using merge if conflicts appear
4) you can check-out another revision of your design and compare both versions using "compare/merge models" or "import of Data Modeler design"
Thanks for the clarification. I have the book but haven't had time to read it. Guess I need to make time. Until then, if it isn't too much trouble, I have another question.
I checked out the latest version into a new WC2. I decided I don't want to do anything with WC2. How do I get rid of WC2? If I just delete the folder in the OS, will SVN server get confused? How do I undo a checkout?