17. Improving Database and Query Performance : Design Issues and Performance : Key Design and Performance : Surrogate Keys and Performance
 
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Surrogate Keys and Performance
When you use a short surrogate or internal key to replace a bad key, or because there is no good key, consider the performance trade-offs. The set processing of data includes the overhead of deriving the key.
Surrogate key types include:
Natural
Universal (a social security number or zip code are examples)
Environmental
These are local to an organization, like an employee number.
Design artificial. These are:
Local to an application
Hard to remember
Hard for users to understand
Can be hidden from users