Gerard,

The int is probably the fastest calculationally because there is no conversion to/from ASCII, provided your data fits in it. Int takes 4 bytes.

If you need to use N fields make sure they are appropriately sized, using n(13,2) for everything is probably a non-optimal solution.

>I have a Data Warehouse type application which uses very large files with lots of fields (Typically 130 fields in each table)
>
>These have always been set up as N(13,2), and they take up a lot of space
>(If I zip them I can get 90 % reduction)
>
>I;m wondering if I use some of the other data types will they:
>1. Increase Processing speed
> (These are updated regulalrly)
>2. Reduce the size of the tables