CODEWITHSUNDEEP
mysqldjangomultithreadingview
user3599803
user3599803

Reputation: 7034

django sql thread safe?

Assume I have this code:

product = Product.objects.get(name='something')
product.number_sold += 1
product.save()

if during the query number_sold was 10, and then before the save(), this code run at the same time so the query will return 10 again, it means it will save number_sold = 11 twice ? In other words, can two users running this django view can get the same value for number_sold field ?

Upvotes: 2

Views: 218

Answers (2)

Daniel Roseman
Daniel Roseman

Reputation: 599926

You can do this in a single query:

Product.objects.filter(name='something').update(number_sold=F('number_sold')+1)

Upvotes: 3

catavaran
catavaran

Reputation: 45585

To avoid race condition in your multi-thread/process code you should use the F()-expressions:

from django.db.models import F

product = Product.objects.get(name='something')
product.number_sold = F('number_sold') + 1
product.save()

Upvotes: 4

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