Should surrogate key be numeric?
1. While on a data modleing course at Oracle, I was advised NOT to use numeric data types unless you needed to do numeric/arithmetic operations on the attribute. E.g. Even though an account_id is all digits it should still be declared as alpha numeric ( VARCHAR2) as it is NOT really a numeric. This makes sense.
I would like opnions on the above
2. If above advice is taken, then even a surrogate key should be alpha numeric since it does not require arithmetic/numeric computations. However, I have also heard that numerics are better than VARCHAR2 for joins. If this join performance advantage is true, then using a NUMBER data type for surrogate keys should be preferred over VARCHAR2? This overrides the advice in 1 above for join performance reasons.
I would like comments on 1 and 2.
Thanks
Edited by: user4900730 on Jun 16, 2010 12:19 PM