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Author Which my star schema models is better?
Resant

2005-07-05, 3:23 am

I work in consumer goods company and now design OLAP Data Warehouse.
My OLAP tables consist of :
1. Customer - all our customer data
{CustomerID, CustomerCode}
2. Type - type of the goods
{TypeID, TypeCode}
3. Grade - quality grade of material
{GradeID, CustomerCode, TypeCode, Grade}
4. Receiving - material receiving
{ReceivingID, TruckNo, Transporter,...}

I've design 2 kind of Receiving_Fact and don't know which one is better
:
>Model 1

- Receiving_Fact
{ReceivingID, GradeID, Measures}
- Star Schema
CustomerDim & TypeDim dimension will be related to GradeDim dmension

>Model 2

- Receiving_Fact
{ReceivingID, CustomerID, TypeID, GradeID, Measures}
- Star Schema
CustomerDim & TypeDim dimension will be related to GradeID field in

Receiving_Fact

I hope my illustration could be understand well. Model 1 is like
snowflake where dimension related to other dimension. Model 2 is star
schma form which all dimensions related to fact table.

Please help me, which model is better? I'm really confused.

Thanks a lot

Jéjé

2005-07-05, 3:23 am

The model 2 provide a better performance both for querying and cube process
if you have 4 dimensions created (Customer, Type, Grade, Receiving) and if
your cube is optimized, then the process time is better (not link made to
process the cube).

The model 1 is slower, but reduce the disk usage in your database.
In this case AS will always do a link between the fact table and the grade
table to process the cube. (slower)

both schemas works fine.


"Resant" <resant_v@yahoo.com> wrote in message
news:1120529234.304385.315440@z14g2000cwz.googlegroups.com...
>I work in consumer goods company and now design OLAP Data Warehouse.
> My OLAP tables consist of :
> 1. Customer - all our customer data
> {CustomerID, CustomerCode}
> 2. Type - type of the goods
> {TypeID, TypeCode}
> 3. Grade - quality grade of material
> {GradeID, CustomerCode, TypeCode, Grade}
> 4. Receiving - material receiving
> {ReceivingID, TruckNo, Transporter,...}
>
> I've design 2 kind of Receiving_Fact and don't know which one is better
> :
> - Receiving_Fact
> {ReceivingID, GradeID, Measures}
> - Star Schema
> CustomerDim & TypeDim dimension will be related to GradeDim dmension
>
> - Receiving_Fact
> {ReceivingID, CustomerID, TypeID, GradeID, Measures}
> - Star Schema
> CustomerDim & TypeDim dimension will be related to GradeID field in
>
> Receiving_Fact
>
> I hope my illustration could be understand well. Model 1 is like
> snowflake where dimension related to other dimension. Model 2 is star
> schma form which all dimensions related to fact table.
>
> Please help me, which model is better? I'm really confused.
>
> Thanks a lot
>



Resant

2005-07-07, 3:23 am

Thanks a lot, your answer is really help

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