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Dimensional Modeling on SAP Hana

Former Member
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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!

Accepted Solutions (0)

Answers (3)

Answers (3)

Former Member
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hi,

1. there is no SID mechanism while modelling on HANA. As we use extended star-schema in BW, it would be simple star schema while modelling on HANA. the whole process can be mapped and modeled using analytic/attribute and calculation views(created via GUI or SCQLScript) only, which makes modelling much simpler. when data is requested from information view, results sets will be calculated on the fly; hence no usage of aggregates. For SCD mechanism, we will use BODS. BODS provides extensive support for SCD scenario.

2. All ETL functions we used to perform in BW(like loading,filtering, merging data from different sources, transforming data etc) can be performed in BODS. BODS does this job efficiently, thanks to its parallel processing, predefined functions library, scripts etc.in ideal scenario, once data loaded into HANA, we should be able to start data modelling immediately.

However, if we are running BW on HDB then transformation logic can be pushed down to HDB.

3. we do the whole modelling using information views.

Former Member
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Hi,

2) If you require to transform your original data and do data cleansing SAP DS fits here better than LT

3) although HANA is DB it has its own capabilities when it comes to DW/DM.

I would say in case of HANA DB, your dimensions are the Attribute Views,

Former Member
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Hi,

2) Where should this transformation be done. Outside Hana or within Hana?

3) How do you preserve history? How will you implement the SCD's?

Regards,

Rajiv

On Wed, Aug 20, 2014 at 3:45 AM, Kairat Alaichiev <experiencesaphana@sap.com

Former Member
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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