How to do DB update in a single query in django when using an IF condition?

Question

I have the following code -

 testcase = Table1.objects.filter(ID=id,serialno ='1234', condition='False').exists()
 if not testcase:
     c = Table1.objects.filter(ID=id,serialno ='1234').select_for_update().update(condition='True')

Here, I am querying the same DB twice. Is there any way where I can do the filter exists and update in a single query?

Andrey Borzenko · Accepted Answer · 2020-08-22 06:14:05Z

1

Filtering doesn't send a query. I agree with the answer above, but if you want a correction for you code, then this would be correct:

testcase = Table1.objects.filter(ID=id,serialno ='1234')
if not testcase.filter(condition='False'):
     c = testcase.select_for_update().update(condition='True')

answered Aug 22, 2020 at 6:14

Andrey Borzenko

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1 Comment

vp_5614 Over a year ago

Thank you for the correction. I will update my code. Also, will something like this work? testcase = Table1.objects.filter(Id=id, serialno='1234').select_for_update().update(condition=When(~Q(condition='False'), then=Value('True')))

Arjun Shahi · Accepted Answer · 2020-08-22 03:19:09Z

0

You can just use the update method with your filter query.

Table1.objects.filter(ID=id,serialno ='1234', condition='False').update(condition=True)

edited Aug 22, 2020 at 3:19

answered Aug 22, 2020 at 2:52

Arjun Shahi

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