HI,

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>GUIDs are useful if users are not permanently connected. GUIDs are supposed to give unique values (based, in part, on the fact that each network card has a unique serial number). However, GUIDs are fairly long - 16 bytes.

I prefer char type surrogated key. So, if I make it like an GUID in a char format, it will be 32 chars. I am worry that will affects performance in the long run....