Mr or Mrs. 500
"Handling the metadata was the really big challenge for our DW. 250 trials, each with 30-40 distinct tables, adding a new trial a week, I had to develop a dynamic ETL tool that was fed by a metadata repository. Finally, the metadata of an individual trial could and would sometimes change in the middle of a trial."
Steven, I think you are correct that the first versions of the data warehouse model ignored metadata almost completely. In his article, "Information Management: DW 2.0 - Architecture for the Next Generation of Data Warehousing" Bill Inmon addresses this problem in the his latest version of data warehousing, what he calls "DW 2.0". In it he states: "Metadata is the glue that holds the data together over its different states. Amazingly, the first generation of data warehousing omitted metadata as part of the infrastructure."
I have to agree that without sufficient (and automated) metadata together with proper release mechanisms, schema maintenance can and will become a full time occupation.
Unfortunately, one of the realizations I came to when creating the dynamic ETL tool was that there is a real limit to how much you can automate metadata maintenance. If you have a DW with a lot of heterogeneous metadata, and that metadata is not "slowly changing", then yes, management should either realize that schema maintenance is indeed a full-time job and pay for someone to do that, or just don't warehouse your data.
Sometimes, the right answer is "forget it".
I have a cube that is giving incorrect data. If i do a sum and group by query in enterprize manager, i get the correct results, but in the cube via excel it is wrong. The relation ships are setup correctly in the cube editor.
Can anyone please give me some ideas?
Hi Danie, possible causes if the relational query is different from the cube are:
1. Named Query in the Data Source View
2. Measure properties such as AggregateFunction and MeasureExpression
3. Dimension perperties such as IsAggregatable, CustomRollup, RootMemberIf
Viewing 4 posts - 16 through 18 (of 18 total)