Once I create a tamino database with a “schema” and also, add several XML documents to that db. Now if we decided to change the scheme (add a new attribute/element,etc…), how does Tamino handle the scheme evolution scenario ?
Schema evolution is much like natural evolution: you try something and, eventually, it works out the way you wanted it.
Joking aside, as long as you’re just adding elements and attributes and don’t do changes or deletions in the tree, you’re pretty much on the safe side.
The last instance on this, though, is Tamino Schema Editor, which will tell you if the modification can be done evolutionary or if it requires an unload/undefine/define/load cycle.
Let’s assume your change is evolutionary, you still have to cope with the XML instances stored before the change. Assume you’ve added a timestamp element to an existing meta element. Now, newly stored XML instances will have this element, old will not. Right now, there is no possibility to batch update this new feature to all existing documents. For functionality like an SQL UPDATE statement, we’ll have to wait for W3C XML Query.
Best regards, Andreas