Re: Creating indexes on views/BCNF

This may help. Although indexed views are hard to think about.

http://msdn2.microsoft.com/en-us/library/aa214336(SQL.80).aspx

Evan
<aehchua_at_ntu.edu.sg> wrote in message news:2d84c540-db81-47c7-973d-892c27611eab_at_s12g2000prg.googlegroups.com...
> Is there a commercial RDBMS that allows one to create indices on
> views?
>
> I'm asking this partly because of BCNF.
>
>
> A typical BCNF problem is (where -> is a FD)
>
>
> A, B->C
> C -> B
>
>
> which becomes the following relations
>
>
> R_1 [_A_, _C_]
> R_2 [_C_, B]
>
>
> where _X_ denotes an attribute in the primary key
>
>
> since
> R [_A_,_C_,B] is not in 2NF
>
>
> But there's an additional constraint where the equijoin of R_1 and
> R_2
> on C would have the candidate key A,B.
>
>
> Is there a way to express this last constraint (i.e., a candidate key
> on a view) in an implementation system?
>
>
> Cecil Chua
>
Received on Tue Jan 15 2008 - 03:31:45 CET