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Former Member

Row tables Or Column Tables Or both?

I would like to know the basic approach in order to build a new model  in hana ( row tables or column tables or both) ?

Suppose I've a source system for example excel or .csv..etc and different excels consists of different types of data that includes both dimensions and measures and each source file consists of around 500 fields. The source feed comes every day and I need to load each and every field in the database.

Out of these 500 fields and assume 300 are dimensions and 200 are facts, and for reporting for purpose i just need 150 dimensions and 80 measures and some calculated measures. (Infuture, I may need to consider some more dimensions and facts) .

Now my question is,

As the source feed comes every day and I need to load all the fields,

Do I need to create first row tables first as Row tables are preferred for insert operations or Can I go a head with column tables directly?

I just want to know the guidelines to follow , where we need to load some thousand of fields and huge number of rows and at the same time my modeling should be good for reporting as well.

What I am not able to catch is, SAP HANA recommends not to combine row tables and column table for operations otherwise first I load all the data into row tables and then create column tables specific to reporting purpose by using row tables' data? ( I can create some stored procs to load data from row tables to columns tables and run them after data load completes)

Please let me know your inputs.

Thanks,

Sree

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1 Answer

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    Former Member
    Sep 03, 2014 at 02:45 AM

    I am putting my question more simpler.

    Can I load data from row tables to column tables (Only inserts) . Will it affect any performance issues?

    Thanks,

    Sree

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    • Former Member

      Hello Shree,

      For the better performance it is always advisable to store table as a Column Store.

      This can be changed anytime to row store.

      HANA does have a row store and you can create row-oriented tables for some very specific scenarios:

      - Transient data like queues, where you insert and delete a lot and the data never persists

      - Configuration tables which are never joined, where you select individual entire rows

      - When you are advised to by a SAP support personnel


      Also if you are going to create views it only supports column based stored tables.


      Usually performance is better with the Column store.


      For more details you can refer:

      http://scn.sap.com/thread/2025441

      Regards,

      Saurabh