the categories of constraints

	period	setup/hold	uncertainty	applied to	add
create_clock	√	√		node	second assignment will be ignored
CREATE_GENERATED_CLOCK	√	√		node	ignore the new constraint and issue a warning
DERIVE_PLL_CLOCKS	√	√		node
DERIVE_CLOCK_UNCERTAINTY			√		Adds derived uncertainty to any uncertainties explicitly added by the user  Overwrites the user's uncertainty, independent of order
DERIVE_CLOCKS
SET_CLOCK_GROUPS		√		clock
SET_MULTICYCLE_PATH		√		between keepers/clocks
GET_FANOUTS
SET_MAX_DELAY/SET_MIN_DELAY		√		between keepers/clocks
SET_FALSE_PATH		√		between keepers/clocks
SET_CLOCK_UNCERTAINTY			√		their uncertainty is additive to that calculated by derive_clock_uncertainty
SET_CLOCK_LATENCY			√
SET_INPUT_DELAY/SET_OUTPUT_DELAY		√		node(external)	there is another external register connected to the port override the first two lines and a warning would be issued
SET_MAX_SKEW