There’s no special syntax, it’s just another parameter in the scripting call.
system.db.runUpdateQuery("INSERT INTO RecipeSteps (StepNum, Gallons) VALUES (%d, %f)" % (nextStepNum, gallons))
vs.
system.db.runUpdateQuery("INSERT INTO RecipeSteps (StepNum, Gallons) VALUES (%d, %f)" % (nextStepNum, gallons), "the_name_of_my_db_con")