DataObjects

hi, Does anyone have some examples of extending the Validation part of a DataObject? I'm a little slow and the stuff in the manual is not shining a great light on my issue. Essentially it's this:- I have an Actvity (in my case an audit of beach safety) which is linked to a beach and is a long transaction (that is it can take weeks). what I want to do is ensure that when a new audit is entered it cant include a beach that is already subject to an open audit. I've built an insert form that makes this easy but it is still possible for a user to create a new audit by using the back arrow and resubmitting the existing data. I can solve this issue with program logic, but I'm more concerned to have the object deal with it, at least then I can use the same technique for any other object. Oh, and on another issue, if I have a linked object (eg Employee - Dept) how do I reference Dept details within the Employee object after a get_link() ? for example emp = new DataObject_Employee; emp->get(123); emp->get_links(); print ($emp->dept->deptName); ??? - I tried thi sonce and failed and could figure it out Thanks Barry -- Barry Steele <barry@hpfm.biz> hpfm