What is the appropriate way to specify the SDC for "..was determined to be a clock but was found without an associated clock assignment."

Thank you very much, and sorry for the late reply. I could not make it work with get_pins, and switched to get_nodes. This is how the sdc now reads:

create_generated_clock -source [get_ports enc_a] -multiply_by 1 [get_nodes {busRotaryEncoder:busRotaryEncoder|metaA}] -name metaA
 
create_generated_clock -source [get_nodes {busRotaryEncoder:busRotaryEncoder|metaA} ] -multiply_by 1 [get_nodes {busRotaryEncoder:busRotaryEncoder|stableA}] -name stableA

However I get a new warning.

Warning (332088): No paths exist between clock target "busRotaryEncoder:busRotaryEncoder|metaA" of clock "metaA" and its clock source. Assuming zero source clock latency.
 
Warning (332088): No paths exist between clock target "busRotaryEncoder:busRotaryEncoder|stableA" of clock "stableA" and its clock source. Assuming zero source clock latency.
 

Why does quartus detect no path even if there is the above mentioned synchronization?