How do i get a list of all id/primary key for a table. Say i have this table:
class Blog(models.Model)
title = models.CharField()
body = models.CharField()
author = models.ForeignKey(Author)
assume the field author is an Author object. I want to get all the ids of Blog where author=author
i know i can use
blogs = Blog.objects.filter(author=author)
and get all the blog objects in a list form, but how do i get the list IDS/PK? Similar to "Select id from Blog where Author=author"
You can do this using values_list
method.
blogs = Blog.objects.filter(author=author).values_list('id', flat=True)
See more at the Django queryset documentation.
Blog.objects.filter(author=author).values_list('id', flat=True)
values_list()
gives a list of rows, each row a tuple of all of the fields you specify as arguments, in order. If you only pass a single field in as an argument, you can also specify flat=True
to get a plain list instead of a list of tuples.
Blog.objects.filter(author=author).values_list('pk', flat=True)
Put pk
instead id
, just for best practices.
values_list
it returns tuples when iterated over. Each tuple contains the value from the respective field or expression passed into the values_list().
author = Blog.objects.filter(author=author)
ids = author.values_list('pk', flat=True)
# list method get ids without parse the returning queryset
print(list(ids))
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