Composite key , more than 1 business keys

Data Vault 2.0
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1

Hello All,
We have many entities where we have more than 1 business keys (composite key) .
Is it better to have them concatenated together as a single business key or keep them as different columns ? What is the impact of on hub & links on this ?

2

Hi CuriousMind,

Are you planning on hashing your business key to create a unique hash key (SHA256)? If so, you don’t need to concatenate them.

Thanks,

Carl

3

Yes HASH keys will be used as per DV standards .

4

Standard says you can do Natural Key DV, on Snowflake (at least) they can outperform joining on surrogate hash keys.

Concatenating bk is a bad idea, it means all code using that hub will need to de-contatenate them. In fact, you can also keep composite keys in the sats; there is nothing in the standard that says you cannot do this.

5

Hi Patrick,

What would be the benefit of hashing the business keys if Natural Keys outperform surrogate keys?

Thanks,

Carl

6

Hey Carl,

I go into a lot of detail here: https://www.youtube.com/watch?v=8xTAOGK5t-g

Hash Keys: nice for simplified joins, single columns, always binary data type.
Natural Keys: if permitted through compression, will outperform hash key joins.

BUT, you will still have hashing wrt to the record digest, i.e. HashDiff
If you try to do a by-attribute comparison for satellite table loads, the larger the satellite (width and depth) the slower this option will be.

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