sql - What do these trigger errors mean -

-

hey guys earlier. have ran new problem. few steps later in homework needed add additional part trigger. trigger needs subtract 1 number of copies. when number of copies hits 0 should display unavailable. have been trying last few hours figure out , came with. or suggestions appreciated!!

create or replace trigger unavailable_rule  before insert on transaction  each row  begin   if :new.date_rented_out  not null , :new.date_returned null , num_copies=1       update video    set num_copies = num_copies - 1,     status = 'unavailable'    vid_num = :new.vid_num;  else   num_copies = num_copies - 1;  end if;  end; / show errors;  6/4  pl/sql: sql statement ignored   7/15  pl/sql: ora-00971: missing set keyword   13/13  pls-00103: encountered symbol "=" when expecting 1 of f ollowing: := . ( @ % ;   14/2  pls-00103: encountered symbol "end"

your update statement misformed. instead of:

update video    num_copies = num_copies -1    set status = 'unavailable' vid_num = :new.vid_num;

assign num_copies in set:

update video    set num_copies = num_copies - 1,        status = 'unavailable'    vid_num = :new.vid_num;

edit:

your if statement can replaced with:

update video     set num_copies = num_copies - 1,         status = (case when :new.date_rented_out  not null , :new.date_returned null , num_copies = 1 'unavailable'                        else status                   end)     vid_num = :new.vid_num;

Comments

Post a Comment

Popular posts from this blog

ruby on rails - RuntimeError: Circular dependency detected while autoloading constant - ActiveAdmin.register Role -

-
i using activeadmin , have file doing this: activeadmin.register role something--- end however, server gives me error: runtimeerror: circular dependency detected while autoloading constant role /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:461:in `load_missing_constant' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:184:in `const_missing' ~/desktop/boxfox/app/admin/role.rb:1:in `<top (required)>' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:424:in `load' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:424:in `block in load_file' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:616:in `new_constants_in' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:423:in `load_file' /library/ruby/gems/2.0.0/gems/activesuppor...
Read more

c++ - OpenMP unpredictable overhead -

-
i have simple openmp code runs 4 empty threads , reports time: #include "omp.h" #include <sys/time.h> #include <cstdio> double start_time; void process_thread() { } int main(){ struct timeval tv; gettimeofday(&tv, null); start_time = 1000*((double)tv.tv_sec + 1e-6*(double)tv.tv_usec); printf("beginning time: %.3fms ",start_time-start_time); #pragma omp parallel schedule(static,1) for(int i=0;i<4;i++) process_thread(); gettimeofday(&tv, null); double cur_time = 1000*((double)tv.tv_sec + 1e-6*(double)tv.tv_usec); printf("finishing time: %.3fms\n\n",cur_time-start_time); } without openmp running time small , consistent: beginning time: 0.000ms finishing time: 0.050ms beginning time: 0.000ms finishing time: 0.050ms beginning time: 0.000ms finishing time: 0.049ms beginning time: 0.000ms finishing time: 0.049ms beginning time: 0.000ms finishing time: 0.050ms beginnin...
Read more

django rest framework - DRF 3.0: UniqueTogetherValidator with a read-only field -

-
in process of upgrading django rest framework 3.0 2.4.4 , want have read-only user field, failing because 'user' being required uniquetogethervalidator (i think) i have model (excuse typos, simplified , code works fine irl): class examplemodel(models.model): some_attr = models.positivesmallintegerfield() other_attr = models.positivesmallintegerfield() user = models.foreignkey(user) class meta: unique_together = ('some_attr', 'other_attr', 'user') viewset: class exampleviewset(viewsets.modelviewset): queryset = examplemodel.objects.all() serializer_class = exampleserializer def perform_create(self, serializer): serializer.save(user=self.request.user) def perform_update(self, serializer): serializer.save(user=self.request.user) serializer: class exampleserializer(serializers.modelserializer): user = userserializer(read_only=true) class meta: model = examplemodel n...
Read more