CONSTRAINT
carg ::= CONSTRAINT nm ccons.
tcons ::= CONSTRAINT nm.
sql_insert_caller_info(expr, CONSTRAINT, i, "$", state->name);
sql_insert_caller_info(call, CONSTRAINT, param, printed_name, sm->state->name);
sql_insert_return_states(return_id, return_ranges, CONSTRAINT,
select_caller_info_hook(&set_param_constrained, CONSTRAINT);
select_return_states_hook(CONSTRAINT, &db_returns_constrained);