Does anyone out there have experience (good or bad) in building a datawarehouse on AS400 and DB2?
Any relevant links will be appreciated as well.
We have to make a decision for the infrastructure of our datawarehouse. Choices are AS400 + DB2 or Microsoft SQL server.
We are using Informatice...
Yes, many people feel unfomrotable with values for 'Unknown'. They probably don't know how to handle this :-) , what it means in business terminology.
I think that you should indeed load all facts.
If I read your post right you will create a piece of code that will in essence perform a full outer join, to identify which products are the same and which products do not have a match.
Is it possible that one of you products will match several products from your acquisition of vice versa?
If...
If there are lots of types of prices, I would opt for a new dimension price_type. And add another dimension key to the fact.
Your business is the one that decides how often a Unitprice changes. It is up to the designer to handle it as a (slowly) changing dimension or as a fact. It is all in the...
From what you describe I would opt for a fact table.
But it is depended on what the business requirements are. How long do you need to access the history of the prices. How often do they change. Are the prices free (they are not restricted to a certain price range), etc.
I would not discard the idea of putting the facts together in 1 fact table. As they represent movements of patienst relative to the hospital. In that sense arrivals, departures and transfers ARE the same and should be collected in a single fact table. And yes, that means that the non-transfers...
I say that it is dependent on the specific case. If you have many long stay patients, my suggestion works very fine. If you manly have short stay patients, the solution from riverguy and MDX-er works best.
There is not a solution that is the best for all situations. Look at all given approaches...
I say your fact table is fine.
why can't you join it to a time dimension? As long as you fill (or convert) the empty departures with a special date (far in the future), you can join by specifying:
arrival_date <= last day of month
and
departure_date >= first day of month
These last and first...
When reporting with SQL I would look into the CASE statement. The precise syntax for MySQL i don't know.
this is the Oracle syntax:
select credit_code
, sum(case when date='jan2008'
then value
else 0
end) as jan2008,
, sum(case when date='jan2009'
then value...
That is one way. Another way is to store all descriptions in an other table with a composite key: (text_ID, language). All text fields are stored as an ID.
It creates a form of snowflake but you are very flexible in storing all different languages.
Isn't this fact table actually a way to split of the changing aspect of your product dimension? And normalized at that.
Why do you want it this way?
Is it due to the size and the change-rate of the dimension? Or do you specifically want to check the changes? The last can be done by adding an...
The fact table you describe will probably get way bigger then the loan dimension, unless you somehow manage to reduce the number of records. e.g. by holding only 1 year of history. But that will give you 12 * 20 million = 240 million records in the fact table. (this is the space part of the...
I wonder hwo you can run a report on just a fact table. You don't use a date dimension? Are you using surrogate keys in teh fact table, or are you using the keys from teh source system?
Design wise I would say, yes, it is a bad idea to duplicate these fields.
Consider the effects of a change of...
MDXer is right in pointing out to seperate time from date.
When keying everything to 1 timezone, you have to be aware of introduced or hidden date-differences. Espescially if you are dealing with a worldwide 24 x 7 situation.
1am GMT of december 12. is still in december 11 when looking from...
One way I know of to handle this situation is to convert every date record you get from a source system to a specified time-zone (GMT for example) before storing it in the DWH. Next you can keep track of the timezone the event took place (perhaps a seperate dimension).
Hope this helps,
Hans
So, you have a really semi-additive fact. The quota are additive over some dimensions, but not over other (like the hierarchy and (possibly) time).
What I have done is to handle this, is to create an aggregate fact-table, with the correct aggregates (in this case Quota).
So you have a fact...
Is your sample really in line with your described case? you say that the Region level data is different from the sum of the territory quota levels.
Your sample data shows that the region data is the sum of the region data.
Can you give a more detailed description of the non-additive measures...
Yes, treating everything as a SCD type2 shifts the proble to the reporting side, where you have to make adjustments for the additional records.
I think your approach sounds like a workeable solution. Probably would try it myself.
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