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Clarification on zero keys and ghost records


Posts: 85
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(@geekn)
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Joined: 7 months ago

Question 1:

When reviewing the NULL business key section of CDVP2 training, the material says “Hash is computed Constant”.  Does that mean it is just the normal hash of the zero key values of “-1” or “-2”?  Or is it a hash constant (similar to ghost key hash) of “00000000000000000000000000000000” or “11111111111111111111111111111111”? 

Question 2:

The training material indicates zero keys should be "pre-populated in all tables".  In addition, DV2 book (and other trainers here in DVA through their posts) indicate ghost records should also be pre-populated in all tables.  If zero key records are not the same as ghost records, does that mean I need to pre-load every table with three records total (example for hub below)?

HUB_HK                                                                    HUB_BK     

00000000000000000000000000000000                      <NA>          <- Ghost record

<true hash of -1 or hash constant (see question1)>      -1               <- Zero key record: required

<true hash of -2 or hash constant (see question1)>      -2               <- Zero key record: optional

 

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Discussion about ghost records where zero keys and ghost discussion gets blurry...

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