Can someone use the entity relationships in this Logical Data Model (LDM):

Logical Data Model

to explain the entity relationships in this Physical Data Model (PDM):

Physical Data Model

  • and how to specify the foreign keys in the PDM?
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1 Answer 1


I'm not sure that I understood your question...

That said, lemme try to help you.

I undestand the model represents the categorization of 'parties' as begin part of 'segments'. These categorizations are mutable and have to be traceable in time.

Let me humbly present what I think is a more complete LDM, where

  • PARTY is explicited
  • Segment Group Cd is exported as part of the identifying relationship (a solid line)
  • the verbs sentences are more verbose

Better (?) LDM

From this LDM, the straightest derived 3NF (3rd Normal Form) PDM should be (PARTY entity not shown):

Straightest possible 3NF PDM derivation from LDM

The PDM you posted:

  1. is denormalized - MRKT_SGMNT_GROUP comprises both MRKT_SGMNT and MRKT_SGMNT_GROUP entities

  2. is incomplete - it's missing Party_Sgmnt_End_Dttm

  3. states redundant relationships - the two relationships are the same

  4. or, more formalistically, states an incorrect relationship - the identifying relationship (the one represented as a solid line) yelds both key properties from MRKT_SEGMNT_GROUP as key properties to PARTY_SGMNT_HIST, which aren't - just Sgmnt_Id has been derived as part of the PK

With the denormalization presented, the PDM ought to be, with the missing property marked in bold red:

Correct, denormalized PDM

Did this serve as any help? Hope so...

Regards, Marcus Vinicius.


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