You Want To Determine The Location Of Identical Rows In A Table Before Attempting To Place A Unique Index On The Table, How Can This Be Done

You Want To Determine The Location Of Identical Rows In A Table Before Attempting To Place A Unique Index On The Table, How Can This Be Done


  • 31 Jan, 2012

    Oracle tables always have one guaranteed unique column, the rowid column. If you use a min/max function against your rowid and then select against the proposed primary key you can squeeze out the rowids of the duplicate rows pretty quick. For example:select rowid from emp ewhere e.rowid > (select min(x.rowid)from emp xwhere x.emp_no = e.emp_no);In the situation where multiple columns make up the proposed key, they must all be used in the where clause.

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