How to create a LDM table alias for a role playing dimension

How To
#1

I need to create an LDM alias table for role playing dimensions such as date dimension. The behavior should be as follows

  1. In LDM, I should be able to name the alias table differently
  2. In PDM, both these tables should merge automatically and create a single table
  3. Any field added in Table1 should be visible by default in Table2. I should be able to however remove or rename them in Table2
#2

Hi sauravmajumdar,

Thank you for your post. Currently, this synchronization from logical to physical ERD does not support table merging.

Best regards,
Jick Yeung

#3

Thanks Jick. Merger is actually a means to the end for me. Is there any other way to realize logical alias for role playing dimensions? How do you realize this in VP today? I will be happy to explain the problem statement again if that helps.

#4

Hi sauravmajumdar,

We support a feature that lets you define a different set of names for model elements. I am not sure if that suit your need… I have captured a video to show you how it works… Please watch here:

Note: In DDL / database generation, the Original name would be applied.

Best regards,
Jick Yeung

#5

Hi Jick
Thanks, Not quite what the ask is. Let me explain

  1. You are creating LDM datamart diagram. You have a date dimension, that has fields like Date, Month, Year etc. Now you want to create two separate instances of this table a) Open Date Dim and b) Closed Date Dim. The # of fields in these two tables are same, but named differently. E.g. First one has Open Date, Open Month, Open Year while the second has Closed Date, Closed Month and Closed Year and so on
  2. The Open Date Dim and Closed Date Dim are 1:M joined with the Fact table individually on two different Fact table columns. “Open Date Dim”.“Row Id” = Fact.“Open Date Id” and “Closed Date Dim”.“Row Id” = Fact.“Closed Date Id”
  3. Now when you convert this diagram to physical diagram, these two become one single table merged as w_day_d. In other words, the dba knows she does need to create 2 tables, but only 1 will suffice. By virtue of the LDM however, the user knows that he needs to create two aliases (Open and Closed) that will join on different columns in the fact table.

Please do let me Jick if this makes sense. Such dimensions are called Role Playing Dimensions (Date, Employee etc.)

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