Representing Source Access Limitations
Use annotations on the attributes of the source relation
- “$” annotation identifies attributes that must be bound
- “%” annotation identifies un-selectable attributes
- A form-interfaced web-page that requires bindings for X and is able to do selections only on Z.
$ and % annotations help identify feasible binding patterns for sources
- Sb-- are feasible; Sf-- are infeasible;
- Sbbf must be modeled as Sbff filtered locally with binding on Y