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Grouping Star schema tables in Data modules

  • 1.  Grouping Star schema tables in Data modules

    Posted Wed April 07, 2021 10:18 AM
    I want to convert the existing Framework manager module to a Data module. But I don't know how to convert the conformed dimensions in the FM model.
    I have for example an Organisation dimension which is linked to multiple fact tables. In the FM model Presentation view there are several folders and in the folders there are namespaces with the shortcuts to the Business View. So it is possible to create several shortcuts to the same Query subject (in this case the organisation dimension) in different namespaces. This is very useful because you can group related query subjects which is convenient for the end-user.
    I know that I can create a view and folders in a data module, but that is not the same as the shortcut functionality in FM.
    How can I achieve this in a data module?

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    Thomas van der Meer
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  • 2.  RE: Grouping Star schema tables in Data modules

    Posted Thu April 08, 2021 10:31 AM
    Unfortunately, Data Modules do not have the shortcut functionality.  To achieve a similar implementation, it would require virtual copies of the dimension table.

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    Landon Akins
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  • 3.  RE: Grouping Star schema tables in Data modules

    Posted Thu April 08, 2021 10:23 PM
    Data Modules are more oriented to end-user data manipulation, usually for ad-hoc purposes.  It's not a robust solution such as FM. e.g. You may alter your organisation dimension and that will flow into all the FM packages.  When using data modules, a change in the source table probably will break them and the only way to fix it is to go into the specs code of the data module and manually change it. 
    Not sure why IBM pushes data modules over FM when FM is the distinctive advantage in CA over competitors.  Data Modules are great for users self-service and data preparation but are not an enterprise-level solution for data modelling. 
    Where I work we continuously improve dimensions, so using data modules will produce a huge increase in the maintenance cost. On the other hands, data modules are great for proof of concepts or to support ad-hoc reports or dashboards.  Data Modules can efficiently be used to replace/automate an excel report. On the other hand, framework is unmatched when you use well-structured packages to create hundreds of reports or query business data.

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    Mauro Santos Otero
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  • 4.  RE: Grouping Star schema tables in Data modules

    Posted 25 days ago
    Edited by Maarten den Dunnen 25 days ago
    Yes, DM is not yet the full replacement of FM. It lacks still some of the features FM has. But in my experience, it has a lot of potentials and depending on what your case is it is already a substitute for FM. It only takes another approach to how you do things. Is it a full replacement of FM already. NO !! But it isn't as bad as you make it be.

    I'm not sure why IBM is not focussing more on the DM part to make it complete as FM. To my knowledge, there is no active development on FM from an innovation standpoint. Sow that should mean that all Dev is on DM, but then there are not many new updates in 11.2 for DM sow I hope in the upcoming releases they add some of the functions that will make DM a true replacement.

    the list is still long,...
    https://www.ibm.com/docs/en/cognos-analytics/11.1.0?topic=dmfm-framework-manager-features-not-supported-by-data-modules

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    Maarten den Dunnen
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  • 5.  RE: Grouping Star schema tables in Data modules

    Posted 25 days ago
    > the list is still long,...

    And the options Use and Display Filter Item are not even on the list. Makes me cry. 


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    Ralf Roeber
    https://linkedin.com/in/ralf-roeber-470425a/
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  • 6.  RE: Grouping Star schema tables in Data modules

    Posted 25 days ago

    I agree with Mauro. Since IBM ​​enhances only data modules both have their strenghts and weaknesses by now. For our future use cases I prefer a mixed model: 

    1 FM Package (all detailed data enriched with FM functionality) > N Data Sets (aggregated for specific use cases) > N Data Modules (enriches DM functionality) > N+ Dashboards/Reports (easy to create on DM) 

    Because we're using an old CQM DMR FM Package we need the Data Sets in between. With DQM it might be possible to skip Data Sets and build Data Modules directly on top of the FM Package (but the performance boost from the Data Set aggregation would be lost). 

    I'd be glad to receive comments on our approach. 



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    Philipp Hornung
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  • 7.  RE: Grouping Star schema tables in Data modules

    Posted 25 days ago
    I've sent you a private message but, to my understanding, this can be done. and is not so difficult only a different approach then FM.

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    Maarten den Dunnen
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  • 8.  RE: Grouping Star schema tables in Data modules

    Posted 25 days ago
    Hi Thomas,

    The official documentation says : In both modeling tools, you can create reusable objects and layers of abstraction.

    regards,

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    Vivien
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  • 9.  RE: Grouping Star schema tables in Data modules

    Posted 20 days ago
    You can achieve single point of definition for star schema s with conformed dimensions with DataModules. Just create one DM for all your facts and dimensions. Then for every starschema make a presentationlayer by defining a new DataModule based on the first big DataModule.

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    Ber Hommelberg
    a.s.r.
    Netherlands
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  • 10.  RE: Grouping Star schema tables in Data modules

    Posted 19 days ago
    Edited by Maarten den Dunnen 19 days ago
    Exactly !!! Like Ber Hommelberg said.

    I only make separate DM's but the concept is the same. I call them Conform DM's and put them in a separate source folder
    1: Conform: Time_DM  (with al my Time_Dims and (Alias)) 
    2: Conform: Regular_DM, (all the regular Dims and Alias)
    3: Conform: Fact_DM (All my Fact tables)

    In these DM's I select the Dims from my DB/DWH  source and add them to the DM.
    From here I make the properties that I want and the presentation correct. (Here you also make your alias Dims if nesseseray)
    You do not set joins in these DM's. You end up with the Ingredients for making the Starschema's.

    In my business folder, I make the new star schema, open been new DM and as a source select the Conform DM's as Source.
    Only have to select the dim and fact that I want for the star schema. Drag and drop from the source into the DM. Set your joins, and add maybe additional calculations for your schema. (remember, Fact and Dims are Green, you cannot change them here only in the original Conform DM).
    and voila you're done. making your new starschema in DM.


    Is there a new Item in your Product dim ? No problem. Go to the "Conform: Regular_DM" and add the item from the DB source to the existing Product_Dim.
    Make any name modifications en properties and save the DM. Every other Star schema that is using the Product_Dim from the "Conform: Regular_DM" automatically get the new Item visible.

    1: DB -> Conform DM
    2: Conform DM -> Starschema DM

    3: optional, If you have multiple Starschem DM, you can add these all together in 1 BIG presentation DM.


    Hope this helps if you are switching from Framework to Data modules:
    It can be done, and it is not that hard, BUT the approach is different from  Framework manager.




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    Maarten den Dunnen
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  • 11.  RE: Grouping Star schema tables in Data modules

    Posted 18 days ago
    Hi Maarten den Dunnen,very nice idea!
    this is for now the approach to have with Data Module...
    But looking at features and easiness of doing and velocity I miss a lot the FM star schema grouping feature,where you can do all this with a right click...

    the list is still long...like Ralf Roeber said.


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    Magnum BI
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  • 12.  RE: Grouping Star schema tables in Data modules

    Posted 18 days ago
    Hi magnum, 

    Yes the list is still long and I also miss a lot of options to let DM work better or faster for me.

    But, what you mention on speed and velocity you are approaching DM Like FM. There is a problem. DM does not have the same work structure you have with FM.
    In that way I found it to be faster on most of (MY) use cases. (DWH, Starschema, kimball, slowchanging dimensions). 

    In FM you spend more time on de DB layer and Business layer, making the star model for your presentation layer is very fast. 
    But DM dos not work in that same process of thinking, and if you force it to be like FM, then DM will never work in the same way you would like it to do.

    I do not say this as an IBM or Cognos defender, BUT almost everybody that had the same problem with that DM sucks,.. and took them on a short course of how to, did not have the same conclusion afterwards. Is it perfect..?? hell no, but it deserves more credit than it now gets.
    (And just for the record I'm working with FM sinds it came available in C8 and build many many FM for customers and in all these years I still learn new things to use FM )



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    Maarten den Dunnen
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  • 13.  RE: Grouping Star schema tables in Data modules

    Posted 18 days ago
    Hi, I don't see that kind of competition. We use the FM with all it's power on top of a detailed data warehouse. For aggregated data marts we use Data Sets on top of the FM Package and Data Modules on top of the Data Sets. That works perfectly and gives us best of both worlds. And the extra effort isn't that big.

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    Philipp Hornung
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  • 14.  RE: Grouping Star schema tables in Data modules

    Posted 7 days ago
    I wouldn't recommend the use of data modules over FM.  In my organisation, we have been trying to use it as a FM replacement and we found it buggy and not reliable. Sometimes the data modules have validation errors and we need to close & reopen for them to work.
    There are other bugs such as the inability of Custom Tables to do a distinct count. This halted a major work started in Data Modules and now the work needs to be re-started on FM. 
    It works fantastic as a data preparation tool or end-user simple modelling tool, but it doesn't provide the reliability required for enterprise reporting.
    It could get better in the future, but as of 11.1.7 is not ready for enterprise-level reporting.  (11.2 seems to only bring another change of UI and TWO new charts)

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    Mauro Santos Otero
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