python 2.7 - Updating entire column with data from tuple in PostgreSQL(psycopg2) -

-

first of all, there script:

import psycopg2 import sys  data = ((160000,),         (40000,),         (75000,),         )  def main():     try:         connection = psycopg2.connect("""host='localhost' dbname='postgres'                                          user='postgres'""")         cursor = connection.cursor()         query = "update planes set price=%s"         cursor.executemany(query, data)         connection.commit()      except psycopg2.error, e:         if connection:             connection.rollback()         print 'error:{0}'.format(e)      finally:         if connection:             connection.close()  if __name__ == '__main__':     main()

this code works of course, not in way want. updates entire column 'price' good, updates use of last value of 'data'(75000).

(1, 'airbus', 75000, 'public') (2, 'helicopter', 75000, 'private') (3, 'falcon', 75000, 'military')

my desire output like:

(1, 'airbus', 160000, 'public') (2, 'helicopter', 40000, 'private') (3, 'falcon', 75000, 'military')

now, how can fix it?

without setting database on machine debug, can't sure, appears query issue. when execute

update planes set price=%s

i think updating entire column value being iterated on data tuple. instead, might need tuple dictionary

({'name':'airbus', 'price':160000}, {'name':'helicopter', 'price':40000}...)

and change query to

"""update planes set price=%(price)s name=%(name)s""".

see bottom of this article similar formulation. check indeed issue, execute query once (cursor.execute(query)) , bet full price column filled first value in data tuple.


Comments

Post a Comment

Popular posts from this blog

ios - Memory not freeing up after popping viewcontroller using ARC -

-
hi project arc based, using uinavigationcontroller make transition between viewcontroller. using profiler analyse happening behind scene memory. noticed when push viewcontroller allocate memory components , when pop not freeing allocated memory. since using arc unable implement dealloc or release component. have analysed in detail , there no memory leak in project. i not using strong property push viewcontroller. here how pushing viewcontroller. viewcontroller *obj = [[viewcontroller alloc] init]; [self.navigationcontroller pushviewcontroller:obj animated:no]; any clue whats going on? should free memory have consumed. please advise your description indicates have retain cycle, leads objects not being deallocated. typical source of retain cycles properties assigned loading nib files (usually declared iboutlet ). two strategies break them , release objects: declare property weak : @property (nonatomic, weak) iboutlet uilabel *statuslabel; set property nil in...
Read more

Django REST Framework perform_create: You cannot call `.save()` after accessing `serializer.data` -

-
i have following viewset: class artistprofileviewset(viewsets.modelviewset): queryset = artistprofile.objects.all() serializer_class = artistprofileserializer def perform_create(self, serializer): if serializer.is_valid(): serializer.save() with following serializers: class simpleartisttrackserializer(serializers.hyperlinkedmodelserializer): class meta: model = artisttrack fields = (...my fields...) class artistprofileserializer(serializers.hyperlinkedmodelserializer): owners = userserializer(many=true, required=false) tracks = simpleartisttrackserializer(many=true, required=false) class meta: model = artistprofile fields = (...my fields...) i getting following error: assertionerror: cannot call `.save()` after accessing `serializer.data`.if need access data before committing database inspect 'serializer.validated_data' instead. i don't see editing serializer.data object. th...
Read more

Why does Go error when trying to marshal this JSON? -

-
i'm trying rather simple example of trying decode json file structs using golang. however, when attempting error that json: cannot unmarshal object go value of type []main.track which don't understand. here's code in question, , json can found here . package main import ( "encoding/json" "fmt" "net/http" "os" ) // tracks group of track types type tracks struct { tracks []track } // track represents singular track type track struct { name string url string artist artist } // artist represents single artist type artist struct { name string mbid string url string } func main() { url := "http://ws.audioscrobbler.com/2.0/?method=geo.gettoptracks&api_key=c1572082105bd40d247836b5c1819623&format=json&country=netherlands" response, err := http.get(url) if err != nil { fmt.printf("%s\n", err) os.exit(1) } de...
Read more