Showing posts with label facts. Show all posts
Showing posts with label facts. Show all posts

Thursday, March 22, 2012

current users

Is there a limit on how many concurrent users that can use SQL Server 2005 Express Edition?

I haven't been able to find any facts about that

Hi,

no there isn′t and there never has been. MSDE either didn′t havelimited concurrent users, the workload governor only throttled the query performance for more than 5 users.

HTH, Jens Suessmeyer.

http://www.sqlserver2005.de

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Jens is correct, we do not limit the number of concurrent users in SQL Express. We have also removed the workload governer in SQL Express as well. Check out Euan Garden's Blog for a historical discussion on the workload governer in MSDE.

http://blogs.msdn.com/euanga/archive/2006/03/09/545576.aspx

Mike - SQL Express team

sql

Wednesday, March 7, 2012

Cube with more that one facts Table

Hello,

I made an illustration, that describes the szenario. There is one Master, one dimension and a second facts table. The Master Table holds up all objects. Sometimes I have additional Information for some objects in Master Table. They are stored in extra tables like the table Optional_facts_for_villas.

My question: How can I combine these two fact tables in Cube Designer without doing a Full outer Join in my Database?

The reason why I want it this way, not all optional_fact_tables are necessary now for OLAP, but maybe later. So, I thought, easiest way would be, adding them later to the cube, without changing the database.
Sorry for my english, its not the best :)

SilasYou forgot to mention which version of SQL Server you are using. As far as I remember this should be possible by using SQL Server 2005, but not SQL Server 2000.|||Ok, it's 2000. I think I will use the full outer join ;)

Saturday, February 25, 2012

Cube from denormalized table: Several dimensions vs. one dimension with several attributes

Hi,

I want to build a cube in AS2005 from a denormalized table.

The table consists of facts from the last three years, with all interesting attributes (about 12) in a seperate column of this table.

Actulally this attributes would form three dimensions (semantically).

I thought of two different approaches to structure the cube:

1. Building a separate dimension for each attribute

or

2. Building three dimensions (or to be more radical : one dimension) that contains all attributes

In my understanding, with the new concept of attribute based hierarchies, both variants should have the same effect on aggregations, performance and so on.

Only difference would the structure shown to the user .

Is this right?

Does autoexist have any influence on the both design variants?

It seems like modeling each attribute as a separate dimension would be a lot easier to use for analysis, right?|||

That is entirely not so.

When designing your model, you should group attributes into dimensions. For instance if you have geographical data , like Country, State, City, you should build a single dimension and create hierarchy.

Analysis Services although allows you to create model from almost any type of schema, you should try to follow the relationships between entities in relational data. That is you should design multideimensional model as if data as normalized as possible.

Having 3 dimensions with multiple attributes sounds like better idea.

Edward.
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This posting is provided "AS IS" with no warranties, and confers no rights.

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Thank you Edward, for your reply.

That is what I supposed to do, but:

As I mentioned, the table contains facts from several years. Within this time, there are dimenions, in which some attributes changed. (Refential integrity in the denormalized table is destroyed)

So when I'm trying to process a dimension with several attributes directly on the table, I get the "key duplicate" error from the processing engine.

To build a model with 3 dimension contailing several attributes woud lead to a reverse design of a slow changing dimemsion, with surrogate key for each attribute combination and timestamp etc......

This is what I wanted to avoid if possible! So I thought of building a dimension form every single attribute in the table. Then historical changes of attributes stay related to the facts correctly.

As I found in another whitepaper, a dimension in ass2005 is nothing more than a logical container for attribute dimensions.--> Is this right ?

So what would be the advantages grouping attributes to dimensions.

As I am quite new to OLAP and MDX I haven't an overview on the technology by now. Are there any disadvantages when later querying the cube? (Restrictions, performance)

Thanks,

Keme

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The problem with creating dimension per attribute would come when your users will try to analyze the data , they run into problems trying to make sence out of the numbers.

You might be saving yourself some time by treating attributes as separate, but if they are logically related, your users will tell you that numbers are wrong. You'd have to come back and build hierarchies and work out through processing errors. Analysis Services are very good pointing out inconsistencies in data.

Edward.
--
This posting is provided "AS IS" with no warranties, and confers no rights.