Creating indexes on views/BCNF
From: <aehchua_at_ntu.edu.sg>
Date: Mon, 14 Jan 2008 16:38:24 -0800 (PST)
Message-ID: <2d84c540-db81-47c7-973d-892c27611eab_at_s12g2000prg.googlegroups.com>
Is there a commercial RDBMS that allows one to create indices on views?
Date: Mon, 14 Jan 2008 16:38:24 -0800 (PST)
Message-ID: <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 - 01:38:24 CET