9 Replies Latest reply: Mar 6, 2010 8:37 PM by Abdul Feroz Raja Sheik RSS

extended star schema

afzal ma
Currently Being Moderated

hi

 

if you load transaction data without loading masterdata will that follow extended star schema or any other schema?

  • Re: extended star schema
    Mansi Dandavate
    Currently Being Moderated

    It doesnt depend on loading whether it follows extended star schema or any other schema.

    If the master data is shared between the InfoCubes then it is called extended star schema otherwise it is Normal Star schema.

    SAP BI follows extended star schema.

     

    Let me know if you need more clarification.

     

    Regards,

    Mansi

    • Re: extended star schema
      afzal ma
      Currently Being Moderated

      Hi Mansi

       

      my question is when you load transcation data witout masterdata is that follow extended star schema, ? as per the defenition of ecxtended star schema: masterdata has to be there in masterdata tables, if masteradta is not there does it called extended star schema? if not how does it work,.

       

       

      Thanks in advance.

      • Re: extended star schema
        Mansi Dandavate
        Currently Being Moderated

        Hi,

         

        In the InfoPackage/DTP you have the option so load data only if master data exists.

        If you dont select that option, that means you are loading transaction data also without loading master data as the case you are mentioning.

         

        So in that case Master data entries are created in the S table i.e. SID Table.

         

        Eg. you are loading a cube which has 0MATERIAL, and you havent loaded the master data of 0MATERIAL.

         

        So in that case whatever values of material are loaded there are also loaded in the S table.

        I.e. /BI0/SMATERIAL.

         

        IF you check the data of 0MATERIAL InfoObject now then you will see only those values of Material which are there in the cube, and all the attributes will be #.

         

        Because in an InfoCube, Fact table is connected to Dimension table which is further connected to SID Table.

         

        So there has to be values in the SID Table.

         

        This is the way Extended Star schema works.

         

        Regards,

        Mansi

      • Re: extended star schema
        Rambabu velanati
        Currently Being Moderated

        Hi,

         

        The main difference between Star schema and extended star schema

         

        In the star schema, Master data stores with in the Fact table.

        there is no SID concept .

         

        In the extended star schema, Master data stored out side of the Fact table.

        Here, when you activate the master data object, the system will generate SID tables for master data > SID tables > SIDs will links to DIM tables ( DIM IDs) of the Fact table.

         

        even if you dont load master data also you can load transaction data, But you have to choose the option in the infopackage "Load the transaction data without master data". Otherwise it will throughs the error of SID issue.

         

        so, if there is no master data, nothing is there to link to Dimension tables of the fact table. So you can directly load the transaction data. 

         

        concept wise, we can call it as a extended Star Schema/ BI star schema, But whether you can load master data or not. Thats depends on requirement.

         

        i hope it will help you

         

        Regards.

        Rambabu

  • Re: extended star schema
    MANISH SHAH
    Currently Being Moderated

    Hi,

     

    You can load transaction data without master data, but if you are updating some field through master data in update rule than it may not correctly updated. Also if you are using master data in query designer (display or navigation attribute) than you may face problem.

     

    Regards,

    Manish

  • Re: extended star schema
    Brian Yang
    Currently Being Moderated

    I think you need to check the defination of star schema and extended star schema.

     

    In SAP BW, if you load transaction data before master data, you have following choice :

     

    1. in the infopackage, you can choose "ignore and load into cube" or "set as error". I am not sure about the exactly decription of them, you need to check it in the infopackage

     

    2. If you load into cube , system will create SID and may have SID error in the future

    3. if you choose not load to the cube, the record which do not have the corrspondance master data will not load into cube.

  • Re: extended star schema
    Tansu Aksu
    Currently Being Moderated

    Hi

     

    The extanded star schema is nothing but shared master data tables.

    The regular star schema consists of dimension and fact tables.

     

    I'm wondering what you are trying to do with this information, becuase you can't control this anyways.

     

    Cheers

    Tansu

  • Re: extended star schema
    KK Singh
    Currently Being Moderated

    The basis difference between star schema and extended star schema is that.

    In former the master data is stored in Dimension table.But,in Extended star schema

    the master data is stored in Seperate Master Table.

    When we a loading the transactional data ,at the infopackage lebel we have option

    load transactional without master data.So,we can load the transactional data without master

    data.In Bw we use only extended star schema.Dimensional table linked with Master table with the help

    of SID .Whenever we activate the characterstics the sid table is created .So,for each charterstics

    sid key are generated .Hope this will be helpful for u.

  • Re: extended star schema
    Abdul Feroz Raja Sheik
    Currently Being Moderated

    Dear friends,

    In Ext Star Schema even if u if you load transaction data without loading masterdata System automatically generates SID with respect to the cube containing transaction data and store in the Master table referring to a navigational attribute.

    To be more clear to ur question, If u are using a BI system its understood that what ever the loading you do will follow Ext Star Schema.

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