Re: Help about a data type

> Hi:
> What data type is better for a field that will contain a number from a
> arithmetic operetion never will be made (like product code, telephone
> number, etc) ?
 

> Is it better numeric, alphanumeric or is it the same ?

it shouldn't matter that much. The advantage of a numeric type is that you get the 'syntax-checking' for free; the disadvantage is that it migt be prove too restrictive. I.e., having a '-' or '()' in a phone number could be useful, and product codes might actually change and starting including letters as well as digitis.

On the whole, I prolly would go for an alpha-numeric type, with explicit syntax checking when entering. Another advantage of this that you can more easily do wildcard searching (if you database supports it).

If speed is a concern, you may want to test which types perform faster on your system; often there is a difference between the two (with numerics typically being faster).

                                                                      Philip

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Philip Lijnzaad, lijnzaad_at_ebi.ac.uk \ European Bioinformatics Institute,rm A2-24
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