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What is the main Motive of Referential Join in Hana, How it will differ with other joins.

Hi Floks,

Could someone help me in knowing more about Referential join.

I had gone through many post in SCN but I am not understanding properly. I know this question had been asked in the forum but from that discussions I didn't get proper functionality

I have understood that the referential join should maintain Referential Integrity between the tables . but what result will it give, If only few columns from left table have corresponding entry from the right table and other columns doesn't have corresponding entry from right table.

Regards,

VaraPrasad.

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4 Answers

  • Best Answer
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    Former Member
    May 30, 2017 at 01:12 PM

    Hello Vara,

    This is how actually Refrential join behaves separately in Attribute and Analytical Views. It does not work for Calculation Views.

    • Referential join in Attribute View:

    Referential join will work as inner join even if we don’t select columns to the output from right table.

    • Referential join in Analytic View:
    • Referential join will as inner join if we have columns from the right table in the output.
    • Join will not executed if we don’t have columns from the right table in the output.

    Thanks

    Neha

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  • May 31, 2017 at 05:39 AM

    Hi Neha,

    Thanks for your update .

    I have one more which I have not clarified yet from your answer is How the Referential join will work in attribute view if you select the columns from the right table too?

    will it work as Inner join only?

    Thanks,

    VaraPrasad.

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    Former Member
    May 31, 2017 at 12:05 PM

    Hello Vara,

    For Inner join we should have common data from both the tables.

    Referential Join is also semantically a inner join that assuming referential integrity is given which means that the left table always have an corresponding entry on the RIGHT table.

    It can be seen as an optimized or faster inner join where the RIGHT table is not checked if no field from the RIGHT table is requested. That means that the Referential Joins will be only executed, when fields from both tables are requested. Therefore, if a field is selected from the RIGHT table it will act similar to inner join, and if no fields from the RIGHT table is selected it will act similar to a left outer join.

    Yes definately it will work as inner join if you select the columns from the right table too.

    Hope it answers your question.

    Regards

    Neha

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  • Jun 13, 2017 at 08:29 AM

    Hi Neha,

    Small correction for your answer.

    • Referential join in Analytic View:
    • Even If we don’t have columns from the right table in the output then join will executed and that is left outer Join.

    I have tested without including the columns from the right table in analytical view its working fine for me.

    Thanks,

    VaraPrasad.

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