XPost: comp.databases.oracle.misc, comp.databases.oracle.server   
   From: mcstockX@Xenquery   
      
   "Agoston Bejo"  wrote in message   
   news:cl8ba7$d04$1@news.caesar.elte.hu...   
   | I want to enforce such a constraint on a column that would ensure that the   
   | values be all unique, but this wouldn't apply to NULL values. (I.e. there   
   | may be more than one NULL value in the column.)   
   | How can I achieve this?   
   | I suppose I would get the most-hated "table/view is changing,   
   | trigger/function may not see it" error if I tried to write a trigger that   
   | checks the uniqueness of non-null values upon insert/update.   
   |   
   |   
      
   did you try a standard UNIQUE constraint on the column?   
      
   unlike SQL-Server (unless they've changed it since I last worked on it),   
   Oracle processes null values properly in this scenario (i.e., one NULL value   
   is never consider equal to another NULL value)   
      
   ++ mcs   
      
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