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Teradata - Difference between Teradata Primary Index and Primary Key ?




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asked vishnoiprem August 17, 2014 05:30 AM  

Difference between Teradata Primary Index and Primary Key ?


           

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answered By vishnoiprem   0  

One must not get confused between Primary Key and Primary Index in Teradata. Primary KEY is more of a logical thing however Primary INDEX is more of physical thing. In Teradata,
Primary INDEX is used for finding best access path for data retrieval and data insertion and Primary KEY is used for finding each rows uniquely just like in other RDBMS. So below are few differences between PRIMARY KEY and PRIMARY INDEX:

PRIMARY KEY
  • PRIMARY KEY cannot be NULL
  • PRIMARY KEY is not mandatory in Teradata
  • PRIMARY KEY does not help in data distribution.   
  • PRIMARY KEY should be unique.
  • PRIMARY KEY is logical implementation.

PRIMARY INDEX
  • PRIMARY INDEX can be NULL
  • PRIMARY INDEX is mandatory In Teradata
  • PRIMARY INDEX helps in data distribution.
  • PRIMARY INDEX can be UNIQUE (Unique Primary Index) or NON UNIQUE (Primary Index).
  • PRIMARY INDEX is physical implementation.
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