1. Hi Raj, Thanks a lot for this post.I’m working in Teradata to Oracle migration project.for UNIQUE PRIMARY INDEX(PSTM_ID,PSTM_ATM,TAX_ID) changed like PSTM_ID as PRIMARY KEY and PSTM_ATM ,TAX_ID both with NOT NULL UNIQUE but bit confused with PRIMARY INDEX( PSTM_ID,PSTM_ATM,TAX_ID) as PRIMARY INDEX can be NULL, UNIQUE or NON UNIQUE.How to modify the same in Oracle?

    1. Author

      Hi Sakthi
      Technically, yes you can have NULL in your INDEX column however you should also consider functionally what kind of values can be expected in columns.
      Looking at the column names you have mentioned PSTM_ID,TAX_ID gives the impression as if these are id columns and perhaps the surrogate key columns. So functionally you may never have NULL as the value for such columns.

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