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GeekInterview.com > Interview Questions > Data Warehousing
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Question: Surrogate Key
Answer: Why do we use Surrogate Key? |
| July 07, 2009 06:56:40 |
#2 |
| Simba123 |
Member Since: July 2009 Total Comments: 1 |
RE: Surrogate Key
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Surrogate keys are system generated keys. They are integers.
Surrogate keys are extremely useful when having type 2 data ( i.e. storing historical information)
For ex: Consider one has a table in which a person and his location are stored. Now when his location is changed and we want to keep a historical record of the same, it is stored with a surrogate key that will help us to uniquely identify the record.
This is also a reason that OLTP keys are not used in the warehouse and a seperate dimension or surrogate key is maintained. |
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