rationale behind dimension with Type 0 and missing Type 5

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rationale behind dimension with Type 0 and missing Type 5

Post  priyagan07 on Tue Dec 21, 2010 7:52 am

Can anyone explain in detail on what is the rationale behind having the dimension start with Type 0 and also for the missing type 5

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Re: rationale behind dimension with Type 0 and missing Type 5

Post  BoxesAndLines on Tue Dec 21, 2010 11:07 am

I don't know what you are talking about. Can you rephrase the question?
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Re: rationale behind dimension with Type 0 and missing Type 5

Post  priyagan07 on Wed Dec 22, 2010 12:35 am

I meant on what different scenarios, a Type 0 SCD technique is used? Also why is that there is no type 5 SCD technique?

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Rationale behind SCD Type 0 and why there is no Type 5 SCD

Post  rademola on Wed Dec 22, 2010 10:06 am

Type 0 is only useful for static data which will not change once it is inserted into the DW. An example could be an Insurance data warehosue model which has an accident type dimension..., or just about any static data the architect/modeller has chosen to store as a dimension in the DW. Once it is entered, the data is never updated. There are only inserts of new data. I personally don't see the usefulness for this SCD type because even static data doesn't remain static forever.

I don't know why there isnt a Type 5 SCD but there is a Type 6 which is derived from a mix of types 1+2+3. I guess if you can think of a situation that requires a mix of types 1+4 or types 2+3 then you can call that type 5.

Good luck!


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Re: rationale behind dimension with Type 0 and missing Type 5

Post  BoxesAndLines on Wed Dec 22, 2010 2:23 pm

I only understand and model type 1,2, and 3 dimensions. I've never needed anything else.
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Re: rationale behind dimension with Type 0 and missing Type 5

Post  ngalemmo on Wed Dec 22, 2010 3:50 pm

rademola wrote:Type 0 is only useful for static data which will not change once it
I don't know why there isnt a Type 5 SCD but there is a Type 6 which is derived from a mix of types 1+2+3. I guess if you can think of a situation that requires a mix of types 1+4 or types 2+3 then you can call that type 5.

Good luck!
Oy! Of course, if you use expotentiation, a mix of type 2 and 3 would be a type 8 (2^3) or a type 9 (3^2) depending on your point of view. If you sometimes do different then you need to multiply by pi. So a mix of 2 & 3 that sometimes is treated as a 1 would be a type 25.13272 or a 28.27431.
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Re: rationale behind dimension with Type 0 and missing Type 5

Post  Jeff Smith on Wed Dec 22, 2010 4:30 pm

Most people stick to 1, 2, and 3. I usually refer to columns being type 1 or type 2. It's not uncommon for a dimension table to have a mixture of 1 and 2.

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Re: rationale behind dimension with Type 0 and missing Type 5

Post  rademola on Thu Dec 23, 2010 4:56 am

[/quote]
Oy! Of course, if you use expotentiation, a mix of type 2 and 3 would be a type 8 (2^3) or a type 9 (3^2) depending on your point of view. If you sometimes do different then you need to multiply by pi. So a mix of 2 & 3 that sometimes is treated as a 1 would be a type 25.13272 or a 28.27431.
[/quote]

I dont think so...

Types 1,2 and 3 is what I have ever used (and in some cases I deviate from what the books say and end up with what works!).

Borders on the esoteric/academic what I explained and I did so because priyagan07 asked.

Multiply by pi, common!



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Re: rationale behind dimension with Type 0 and missing Type 5

Post  priyagan07 on Thu Dec 23, 2010 7:36 am

Thanks all for your comments. It was quite informative

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Re: rationale behind dimension with Type 0 and missing Type 5

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