What is the best practice to quickly move specific tables into one new Diagram and retain the lay out? Also prevent tables / entities from being deleted from the entire model when deleted from a specific Subject Area?
First, let us review some of the differences in r8 vs. r7 ERwin:
- Diagrams (in ERwin r8) replace Stored Displays (in ERwin r7), and a Table within a Subject Area may or may not appear in the Diagram that is owned by the Subject Area or a Model
- A Subject Area can have none, one or more than one Diagrams
- The Model need not have a Main Subject Area or a Diagram
- A Diagram can be directly associated with Model without being part of any Subject Area
To quickly move specific tables into a new Diagram's display and retain the lay out, simply copy all of the objects from one Diagram's display and then paste that into the new Diagram's display. That will retain the graphical positions and automatically add just those entities and other objects to the diagram for that Diagram. If you like the Diagram to be associated with a specific Subject Area, then create a new Diagram under the desired Subject Area and then copy from one Diagram (from another Subject Area) to the new Diagram in the Subject Area. It also retains their graphical coordinates, look and feel, etc. That will not duplicate the objects that are pasted into the new subject area's display.
How do I prevent tables/entities from being deleted from the entire model when deleted from a specific subject area?
The way to prevent that is, simply, when you go to delete an entity, you get a window that says,
The selected objects will be deleted from the diagram
Do you also want them deleted from the Model?
To that question, respond No. That will prevent the entities / tables from being deleted from the whole model when attempting to just remove them from a particular diagram.
IF you are not getting the above message, in the past you may have checked on the box "Don't show this again" on the message box. So to reset that message to give you the opportunity not to delete the objects but just remove them from the display, please do the following: go to Tools | Options and then press the button Reset all messages.