Normally UPDATE would be used to output a single value for each variable being output. In the example below variable names are used directly instead of with a surrogate ID. The value of the variables at time 20 will be stored in the database. Constant can clearly be stored in this manner as well but LOOKUPS will not be available.
:CONNECT DATA1
:CONSTANTS
:FIELD scenario=!
:VARLIST
constant2
varible2
:TIME #20
:FIELD scenario=!
:VARNAME VARNAME
:SUB SUB1
:VALUE VARVAL
:UPDATE OUTPUT_CONSTANTS
