Randall,

R> Exception: validation error for variable RATE, value
R> "10.00000000000000" At procedure 'P_TAX_AMOUNT' line: 11, col: 3

apart from the workaround Helen has suggested, have you tried setting
a DEFAULT value for the RATE variable (or the PERCENTAGE domain), or
otherwise initializing the RATE variable? I think your procdure should
work, but I also think using a SP in a check constraint is a
borderline situation and that might be the source of your error
message.

HTH
--
Nando Dessena
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