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View Full Version : Snow flake Schema failed with OUTER JOIN in Meta Data Editor



Houssem EL AYDI
05-07-2009, 03:49 AM
Hi,

Is there any way to represent snowflake schema with metadata editor and get correct SQL outer join query results. :)
I have a geographic dimension which can be divided to the following structure :
Geographic_area/country/implantation/field ==>This is corresponds to the goegraphic dimension.

So for each term has a table in the database.==>4 tables.
Also, i have a simple standard Employe dimension and a fact table which contain as measure the wage of employes.

The aggregation is sum on the wage.

The problem is that when i link this table with outer join(Left or right it doesn't matter) and after that i make a query on the fact table such as :
The total wage grouped by country (e.i:The total wage corresponding the country France, USA...) i get errors or wrong results.

So my quesion is : Is it possible to modelise a snow Flake schema as business View with Meta Data Editor and query it.

Thanks

wgorman
05-12-2009, 08:38 PM
Hi,

Many people model their snowflake schemas in Metadata, you could also look into modeling it using Mondrian. Traditionally Snowflakes don't need outer joins, all the ids in the fact table map to a row in the dimension table. If you post more details, for instance the SQL generated that is causing the problem, that might help debug your problem. You can launch the MQL editor from within pentaho metadata editor by clicking on the query icon in the toolbar.

Will