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Star Schema

From: Ken Chow <kenemail_at_netvigator.com>
Date: 2000/05/20
Message-ID: <8g5mvf$ffd2@imsp212.netvigator.com>#1/1

Hi there,

I have a few questions for implementing star schema in Oracle. Please help. I am going to build a DW for my project where with 4 dimension and one fact table where the definition of the tables are as follows :

A_DIM (A_ID, A_DESC)
B_DIM (B_ID, B_DESC)
C_DIM (C_ID, C_DESC)
D_DIM (D_ID, D_DESC)

THIS_FACT (A_ID, B_ID, C_ID, D_ID, AMOUNT) the optimizer_mode is set to "choose" that the optimizer will use cost-base optimizer after the tables are analyzed. If I have specified all the equal predicates, it's using the star schema plan, otherwise, if just specify a_dim.a_id predicate, the plan seems not in star schema plan like the following SQL. My question is how to force the following SQL in using STAR SCHEMA plan ? thanks.

select amount, a_desc, b_desc, c_desc, d_desc from

a_dim,
b_dim
c_dim,
d_dim,

this_fact
where a_dim.a_id = 3
and b_dim.b_id = 2
and a_dim.a_id = this_fact.a_id
and b_dim.b_id = this_fact.b_id
and c_dim.c_id = this_fact.c_id
and d_dim.d_id = this_fact.d_id;

Ken Received on Sat May 20 2000 - 00:00:00 CDT

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