Porblem with Dimensional modeling

Hi everybody;
I'm new in datawarehousing.
I want to create a datamart about road accident. I have a very simple E/Rship mode :
drivers
1,1
|
|
|
1,N
|
vehicules 1,1-------1,N-accient-1,N ------- 1,1- victime
|
1,1
|
|
|
1,N
|
cause_accident
My physical model :
table cause_accident(code_cause,description,categrie_cause);
table accident (code_accident*,date_accident,region,number_of_victimes,code_cause**);
table vehicule (matricule*,type_vehicule,code_accident**);
table victime (num_victim*,name,age,sexe,code_accident**);
table driver (num_driver*,name,age,sex,code_accident**);
* :primary key
**:foreing key
So I want to create a datamart about raod accident to be able to get some statistics like :
-number of accident per month, year...(time)
-number of victims per month, year...(time)
-number of accident per region
-number of victims per region
-number of accident per vehicule type
-number of accident per victime sex
-number of accident per victime age
-number of accident per driver sex
-number of accident per driver age
I have the fact table "accident"
dimensional tables : times,region
My question is :
how to have the others dimensional tables because we have 1,N (many to many) relation between accident and: driver,victime and vehicule? Really it's not clear for me at all !!!!
Plz I need for your help .
Thank you at advance

If you're new to dimensional modeling I'd suggest the following site:
http://www.kimballgroup.com/html/articles.html
Also worth picking up Ralph Kimball's Data Warehousing book.
Without thinking about this too much, maybe the granularity of the Fact table is per Driver/Vehicle, an Accident dimension can then be used to link the rows that were involved in the accident.
Cheers
Si

Similar Messages

Problem with dimensional modeling

Hi everybody;
I'm new in datawarehousing.
I want to create a datamart about road accident. I have a very simple E/Rship mode :
drivers
1,1
|
|
|
1,N
|
vehicules 1,1-------1,N-accient-1,N ------- 1,1- victime
|
1,1
|
|
|
1,N
|
cause_accident
My physical model :
table cause_accident(code_cause,description,categrie_cause);
table accident (code_accident*,date_accident,region,number_of_victimes,code_cause**);
table vehicule (matricule*,type_vehicule,code_accident**);
table victime (num_victim*,name,age,sexe,code_accident**);
table driver (num_driver*,name,age,sex,code_accident**);
* :primary key
**:foreing key
So I want to create a datamart about raod accident to be able to get some statistics like :
-number of accident per month, year...(time)
-number of victims per month, year...(time)
-number of accident per region
-number of victims per region
-number of accident per vehicule type
-number of accident per victime sex
-number of accident per victime age
-number of accident per driver sex
-number of accident per driver age
I have the fact table "accident"
dimensional tables : times,region
My question is :
how to have the others dimensional tables because we have 1,N (many to many) relation between accident and: driver,victime and vehicule? Really it's not clear for me at all !!!!
Plz I need for your help .
Thank you at advance

If you're new to dimensional modeling I'd suggest the following site:
http://www.kimballgroup.com/html/articles.html
Also worth picking up Ralph Kimball's Data Warehousing book.
Without thinking about this too much, maybe the granularity of the Fact table is per Driver/Vehicle, an Accident dimension can then be used to link the rows that were involved in the accident.
Cheers
Si

How to include Abbreviations in Dimensional Model

Dear All,
The question is basically related to modelling but as I am using OWB for this, I am posing the question here.
I have to migrate a HR database from relational model to dimensional model. I have the following situation.
There is a table which has two columns i.e. Country_cod, and country_name like UK- United Kingdom, US - United States. Then in the database where ever it is needed to use information about the country, the country_cod is used. I want to migrate the database to dimensional model, This table does not relate to any other table directly, like a foreign key relationship.
How should I deal with this situation?
Comment please....
regards

You can put your Javascript code in the Onmouseover property of the column.
I don't have the Javascript code for changing the color but for example the following will pop up an alert
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Are there any (dis)advantages in building a universe on fully normalized tables instead of building dimensional model/tables and then universe on top of them?

Hello,
I’m hoping someone can help me with understanding advantages and disadvantages if we want to build a universe on top of a fully normalized tables, compared to using a dimensional model with star schemas.
I’ve read some discussions here that say that it is possible to create a universe on top of normalized tables. Then, can we avoid building of dimensional tables (a data mart), and just use normalized tables? I would say that it is easier to use star schema dimensions and facts tables to build a universe, but our end users might ask “why do we have to go through building a dimensional data mart, if we can have same reports with hierarchies and drill-down functionality based on a universe built on top of our already existing normalized tables?”
Can you point me to some established best practices regarding using normalized tables to build a universe? Any documents with some examples for this?
Any expected difficulties during design/development phase of our universe, related to using normalized tables?
Any expected performance degradation if we use normalized tables compared to using dimensional tables?
Can I build universe more easily if I transform (modify) our normalized model (by using alias tables and views) to look like snowflake model?
I’m using BOE XI 3.1, tables are in Oracle 11.2.
Thank you

Few Disadvantages that I usually face when building universe on Normalized tables,
1. Performance - Read operations have to suffer because indexing strategies do not go well with table joins
2. Derived Tables - Due to complex Queries/ Logic, most of the time, end-up creating derived tables, which doesn't use back-end table indexes and slows down the report runtime.
3. Normalized table/ Transaction tables may not always have proper cardinality and often results in Cartesian products
4. Normalized tables may not have tight referential integrity and may have to join more than one column and join on varchar, etc whereas, good Dimensional model datawarehouse will have proper keys/ integer joins and not always necessary to join on multiple fields
5. Often deal with Fan and Chasm Traps
6. Dealing with Database fields with nulls, blanks, date in numeric format, etc.,
7. No Facts, Dimensions separated and most of the time they are in same table
and More...
If performance is not a matter and building Datawarehouse is a big deal, then I will start building Universe on normalized tables by having the database diagram as reference for Joins, contexts, etc
Note: After dealing with universes based on normalized tables for few years (by creating views, complex sql queries data loading to tables and unv on these tables, derived tables), I ended up creating star-schema dimensional model (couple of months extra ETL work), users/ developers felt lot better when they have to create standard/ ad-hoc reports and they are super fast compared to previous universes.

Designing Dimensional Model from Reports

I'm currently desiging a data warehouse for our project. My problem is that we do not have access to the source system. The only thing we are provided with is the data feeds that are generated by the current reporting system. This is causing me a great deal of headach b/c reports do not give you an entire picture of what the source system. Since reports only display data based on how it is developed, it is difficult to come up with an efficient design. My question is has anyone designed a dimensional model using only Reports as the source?

Hi there,
The short answer to your question is 'no'
A longer answer is 'Surely it is possible to get a copy of the source schema definition even if it is not possible to get access to the source system?'
Stuart

Dimensional Modeling on SAP Hana

Hello,
I am a newbie on SAP hana, so need help from experts / gurus.
Imagine the following Scenario ---> Oracle ERP is the source System and we want to build a Analytic Solution on Hana. Also assume that tables can be replicated into SAP Hana
Questions
1)For any kind of reporting / Analytics? Should we build a traditional Datawarehouse on Hana with all the features found in a star schema like surrogate keys, conformed facts and dimensions etc? or use only attribute views / analytical views provided as default and build datawarehouse model on top of this? In the second case, do we still need surrogate keys or how can we merge slowly changing dimensions?
2)Where can be push the transformation logic? Into ETL tool or use Hana provided sql script? and also where do we do this transformation, outiside hana where we do all transformations and load only data into normolized format? or within hana using scripts?
3) In any case is dimensional modeling really required on Hana? if not how can we map business process and do analysis on them? is it by means of only the views provided by Hana?
Your help is much appreciated.
Thanks!

Hi Rajiv,
I'm no expert either and am just beginning to learn HANA, but here are my thoughts (community, please correct me if I am mistaken.):
1. HANA leverages existing data modeling theories, such as the entity relationship model. This model is simply a way of organizing tables in a way that makes sense for reporting. For example, the star schema, optimized for analytical reporting. The HANA view is similar to a universe, it allows the end user to connect to it from their BI tool. In the background, the modeler still needs to pull in tables, create joins, leverage primary and foreign keys, etc. So in short, traditional modeling practices and theories still come into play.
2. If extracting and transforming data using SAP's Data Services, the transformation of data will happen in HANA, using the Data Quality Management GUI.
Just as a side note, HANA has 3 methods of extracting
data:
Data Services
SAP Replication
Server
SAP Landscape
Transformation
3. Yes, dimensional modeling is still required. At the end of the day, HANA is still a database. We
haven’t changed the theory of data modeling, it still needs to happen, our approach is just different.
Hope that helps.
Kyle

Dimensional modeling scenario

Hi Experts,
I am having a requirement to do dimensional datamodel for a datawarehouse for the below scenario. Please provide me your suggestions. How many dimensions and facts which i should consider for this? Given below is my requirements.
Percentage and Numbers of care plans due for review, indate or expired
Analysis by home, keyworker, client
Drill down to home by client
Drill down to keyworker by client
Drill down to client
Source OLTP Tables
Patient : (PatientInfo)
=========
clientName
clientAdress
Age
Staff: (StaffInfo/Keyworker)
============
StaffName
StaffDept
DOB
Careplan:(This table will holds Patient Careplans)(1:M)
=========
Expected Outcome (Expected Result of this actionplan)
Current Situation (Current condition of patient)
Action (what is the action taken for the result)
Start Date (patient start)
review Date (for every care plan there will be review date and on that date this record will expire and create a new record with the current situation)
EndDate (End date of patient)
Keyworker(Staff which is in primary charge for this patient- A staff can be keyworker for multiple patients)
thanks
MUS

Hi Rajiv,
I'm no expert either and am just beginning to learn HANA, but here are my thoughts (community, please correct me if I am mistaken.):
1. HANA leverages existing data modeling theories, such as the entity relationship model. This model is simply a way of organizing tables in a way that makes sense for reporting. For example, the star schema, optimized for analytical reporting. The HANA view is similar to a universe, it allows the end user to connect to it from their BI tool. In the background, the modeler still needs to pull in tables, create joins, leverage primary and foreign keys, etc. So in short, traditional modeling practices and theories still come into play.
2. If extracting and transforming data using SAP's Data Services, the transformation of data will happen in HANA, using the Data Quality Management GUI.
Just as a side note, HANA has 3 methods of extracting
data:
Data Services
SAP Replication
Server
SAP Landscape
Transformation
3. Yes, dimensional modeling is still required. At the end of the day, HANA is still a database. We
haven’t changed the theory of data modeling, it still needs to happen, our approach is just different.
Hope that helps.
Kyle

SSRS report with tabular model – MDX query CoalesceEmpty function does not return the provided string value

Hello everyone,
I created following calculated member in MDX query. I am using it in one of the report parameter in dataset (single select dropdown list as report parameter).
WITH MEMBER [Measures].[ParameterCaption] AS
CoalesceEmpty([Customer].[National Account Code].CURRENTMEMBER.MEMBER_CAPTION,'None')
I would like to display 'None' text at the top of the dropdown list values. So that when user selects 'None' then this parameter will not considered in MDX query else the selected National Account Code will be considered to filter report data. But,
the above return blank/empty value for [Customer].[National Account Code].& member though I specified 'None' as text in CoalesceEmpty function. Any advice would be appreciated.
Thanks, Ankit Shah
Inkey Solutions, India.
Microsoft Certified Business Management Solutions Professionals
http://www.inkeysolutions.com/MicrosoftDynamicsCRM.html

Hi Ankit,
It seems that you issue had been solved in your another thread.
http://social.msdn.microsoft.com/Forums/sqlserver/en-US/5a5becac-226f-428a-95b0-aaaa22733818/ssrs-report-with-tabular-model-create-a-dropdown-report-parameter-with-none-option-as-the-top?forum=sqlanalysisservices#0e51bf8c-a66c-4df5-a244-0147728fdfdb
iif([Customer].[National Account Code].CURRENTMEMBER.MEMBER_CAPTION="","None",[Customer].[National
Account Code].CURRENTMEMBER.MEMBER_CAPTION)
I marked this reply as answer, it will benefit to other members who have the similar issue.
Regards,
Charlie Liao
TechNet Community Support

SQL Developer with Data Modeler, No Design Menu Option

Using SQL Developer 3.0.04 Build MAIN-04.34 with Data Modeler. I have created a logical design and wish to forward engineer this to a relational model.
I cannot seem to find the Design Menu option to use the >> Engineer to Relational Model option which is available under the Design Menu on the Stand Alone version of SQL Developer Data Modeler.
Have checked the following locations:
Tools -> Data Modeler
View -> Data Modeler
File -> Data Modeler
Right Click on my Logical Design
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Is this a bug or am I missing a menu option / configuration setting?
Thanks in advance for any help
John

Hi John,
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Philip

Open a pdf with a model.

Hi.
I've a portal application. In a class, I call to one Bapi, and this Bapi return a table and I keep the table into a model. I want open a pdf with my model.
How can I do it? What are the java import?

Hi Jens,
I'm developing a portar archive (.par).
This is the code by which I call the BAPI and it gives back to me the model:
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Problem with distribution model receiver ports

Hi,
I am facing a problem with distribution model.
I am using Distribution model for material classification data. I am sending my classification data using CLFMAS message type to one of the receiver. Again another person also sending classification data to another receiver.
But both objects will run at different times.
Problem is for every run and every change it is creating 2 idocs instead of 1 idoc.
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Hi kotesh,
A similar issue.
check if this will help.
Do the following:
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source:http://sap.ittoolbox.com/groups/technical-functional/sap-interfaces/sap-distribution-model-3008763
Regards,
SuryaD.

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Probably not - although this comes only from personal experiance and not any technical knowlage. I always purchase cd's based on conviniance and not brand. Also spend my life between Europe and North America and have never encontered any cd that would not work - aside occasional lemons.
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Download IBM Book on Star Schema Design (Dimensional Modeling)

Hello Friends,
You can download an IBM Book on Dimensional Modeling from the following link:
http://www.redbooks.ibm.com/redbooks.nsf/e9abd4a2a3406a7f852569de005c909f/e235dc46161249d38525703e00036135?OpenDocument
The Book is very well explained.

Dear Krish,
Please try this link and let me know if you can open.If not I will email you the Book:
http://www.redbooks.ibm.com/abstracts/sg247138.html?Open
My Email is [email protected]
Thanks
Dave

Porblem with Dimensional modeling

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