Django: filter() or get()
0
Is the way I write discount_code.first().is_active() the right way, or is it preferable to work with .get as (discount) code is a code unique field per event? Different events can have the code.
def clean_code(self):
input_code = self.cleaned_data['code']
# Check if discount code exists
discount_code = self.event.discounts.filter(code=input_code)
discount_code_exists = discount_code.exists()
if not discount_code_exists:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
else:
if not discount_code.first().is_active():
raise forms.ValidationError(_("This discount code is not available
anymore."),
code='code_not_active')
return input_code
python django
edited Nov 14 '18 at 16:36
Joel
1,5686719
asked Nov 14 '18 at 16:08
Joey CoderJoey Coder
3069
add a comment |
0
Is the way I write discount_code.first().is_active() the right way, or is it preferable to work with .get as (discount) code is a code unique field per event? Different events can have the code.
def clean_code(self):
input_code = self.cleaned_data['code']
# Check if discount code exists
discount_code = self.event.discounts.filter(code=input_code)
discount_code_exists = discount_code.exists()
if not discount_code_exists:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
else:
if not discount_code.first().is_active():
raise forms.ValidationError(_("This discount code is not available
anymore."),
code='code_not_active')
return input_code
python django
edited Nov 14 '18 at 16:36
Joel
1,5686719
asked Nov 14 '18 at 16:08
Joey CoderJoey Coder
3069
add a comment |
0
0
0
Is the way I write discount_code.first().is_active() the right way, or is it preferable to work with .get as (discount) code is a code unique field per event? Different events can have the code.
def clean_code(self):
input_code = self.cleaned_data['code']
# Check if discount code exists
discount_code = self.event.discounts.filter(code=input_code)
discount_code_exists = discount_code.exists()
if not discount_code_exists:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
else:
if not discount_code.first().is_active():
raise forms.ValidationError(_("This discount code is not available
anymore."),
code='code_not_active')
return input_code
python django
edited Nov 14 '18 at 16:36
Joel
1,5686719
asked Nov 14 '18 at 16:08
Joey CoderJoey Coder
3069
Is the way I write discount_code.first().is_active() the right way, or is it preferable to work with .get as (discount) code is a code unique field per event? Different events can have the code.
def clean_code(self):
input_code = self.cleaned_data['code']
# Check if discount code exists
discount_code = self.event.discounts.filter(code=input_code)
discount_code_exists = discount_code.exists()
if not discount_code_exists:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
else:
if not discount_code.first().is_active():
raise forms.ValidationError(_("This discount code is not available
anymore."),
code='code_not_active')
return input_code
python django
python django
edited Nov 14 '18 at 16:36
Joel
1,5686719
asked Nov 14 '18 at 16:08
Joey CoderJoey Coder
3069
edited Nov 14 '18 at 16:36
Joel
1,5686719
asked Nov 14 '18 at 16:08
Joey CoderJoey Coder
3069
edited Nov 14 '18 at 16:36
Joel
1,5686719
edited Nov 14 '18 at 16:36
Joel
1,5686719
edited Nov 14 '18 at 16:36
Joel
1,5686719
1,5686719
asked Nov 14 '18 at 16:08
Joey CoderJoey Coder
3069
asked Nov 14 '18 at 16:08
Joey CoderJoey Coder
3069
asked Nov 14 '18 at 16:08
Joey CoderJoey Coder
3069
3069
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
2
You can save a query here. The return value of .first() on the queryset has all the info you need for your validation:
def clean_code(self):
input_code = self.cleaned_data['code']
# this is None if it doesn't exist
discount_code = self.event.discounts.filter(code=input_code).first()
if not discount_code:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
Using exists() is only beneficial if you do not need to process the queryset any further (which you do in the is_active check). And even then, you need large amounts of data to see real performance gains.
answered Nov 14 '18 at 16:43
schwobasegglschwobaseggl
37.4k32442
As the statement says, "Explicit is better than implicit". To me, seeingfiltermeans "it can return multiple values", andgetmeans "it should return one value". So I find strange doingfilter().first()instead ofget.
– mistiru
Nov 14 '18 at 17:05
@mistiru I don't disagree, given the uniqueness ofcode. Your solution is principled and perfectly valid. I would, however, consider my approach a bit more readable and tidy as all invalid cases are handled and detected in the same way (if).
– schwobaseggl
Nov 14 '18 at 17:22
add a comment |
1
I would have written the code this way:
def clean_code(self):
input_code = self.cleaned_data['code']
try:
discount_code = self.event.discounts.get(code=input_code)
except Discount.DoesNotExist: # suppose your model is named Discount
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
answered Nov 14 '18 at 16:58
mistirumistiru
440113
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
2
You can save a query here. The return value of .first() on the queryset has all the info you need for your validation:
def clean_code(self):
input_code = self.cleaned_data['code']
# this is None if it doesn't exist
discount_code = self.event.discounts.filter(code=input_code).first()
if not discount_code:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
Using exists() is only beneficial if you do not need to process the queryset any further (which you do in the is_active check). And even then, you need large amounts of data to see real performance gains.
answered Nov 14 '18 at 16:43
schwobasegglschwobaseggl
37.4k32442
As the statement says, "Explicit is better than implicit". To me, seeingfiltermeans "it can return multiple values", andgetmeans "it should return one value". So I find strange doingfilter().first()instead ofget.
– mistiru
Nov 14 '18 at 17:05
@mistiru I don't disagree, given the uniqueness ofcode. Your solution is principled and perfectly valid. I would, however, consider my approach a bit more readable and tidy as all invalid cases are handled and detected in the same way (if).
– schwobaseggl
Nov 14 '18 at 17:22
add a comment |
2
You can save a query here. The return value of .first() on the queryset has all the info you need for your validation:
def clean_code(self):
input_code = self.cleaned_data['code']
# this is None if it doesn't exist
discount_code = self.event.discounts.filter(code=input_code).first()
if not discount_code:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
Using exists() is only beneficial if you do not need to process the queryset any further (which you do in the is_active check). And even then, you need large amounts of data to see real performance gains.
answered Nov 14 '18 at 16:43
schwobasegglschwobaseggl
37.4k32442
As the statement says, "Explicit is better than implicit". To me, seeingfiltermeans "it can return multiple values", andgetmeans "it should return one value". So I find strange doingfilter().first()instead ofget.
– mistiru
Nov 14 '18 at 17:05
@mistiru I don't disagree, given the uniqueness ofcode. Your solution is principled and perfectly valid. I would, however, consider my approach a bit more readable and tidy as all invalid cases are handled and detected in the same way (if).
– schwobaseggl
Nov 14 '18 at 17:22
add a comment |
2
2
2
You can save a query here. The return value of .first() on the queryset has all the info you need for your validation:
def clean_code(self):
input_code = self.cleaned_data['code']
# this is None if it doesn't exist
discount_code = self.event.discounts.filter(code=input_code).first()
if not discount_code:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
Using exists() is only beneficial if you do not need to process the queryset any further (which you do in the is_active check). And even then, you need large amounts of data to see real performance gains.
answered Nov 14 '18 at 16:43
schwobasegglschwobaseggl
37.4k32442
You can save a query here. The return value of .first() on the queryset has all the info you need for your validation:
def clean_code(self):
input_code = self.cleaned_data['code']
# this is None if it doesn't exist
discount_code = self.event.discounts.filter(code=input_code).first()
if not discount_code:
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
Using exists() is only beneficial if you do not need to process the queryset any further (which you do in the is_active check). And even then, you need large amounts of data to see real performance gains.
answered Nov 14 '18 at 16:43
schwobasegglschwobaseggl
37.4k32442
edited Nov 14 '18 at 16:49
answered Nov 14 '18 at 16:43
schwobasegglschwobaseggl
37.4k32442
answered Nov 14 '18 at 16:43
schwobasegglschwobaseggl
37.4k32442
answered Nov 14 '18 at 16:43
schwobasegglschwobaseggl
37.4k32442
37.4k32442
As the statement says, "Explicit is better than implicit". To me, seeingfiltermeans "it can return multiple values", andgetmeans "it should return one value". So I find strange doingfilter().first()instead ofget.
– mistiru
Nov 14 '18 at 17:05
@mistiru I don't disagree, given the uniqueness ofcode. Your solution is principled and perfectly valid. I would, however, consider my approach a bit more readable and tidy as all invalid cases are handled and detected in the same way (if).
– schwobaseggl
Nov 14 '18 at 17:22
add a comment |
As the statement says, "Explicit is better than implicit". To me, seeingfiltermeans "it can return multiple values", andgetmeans "it should return one value". So I find strange doingfilter().first()instead ofget.
– mistiru
Nov 14 '18 at 17:05
@mistiru I don't disagree, given the uniqueness ofcode. Your solution is principled and perfectly valid. I would, however, consider my approach a bit more readable and tidy as all invalid cases are handled and detected in the same way (if).
– schwobaseggl
Nov 14 '18 at 17:22
As the statement says, "Explicit is better than implicit". To me, seeing
filter means "it can return multiple values", and get means "it should return one value". So I find strange doing filter().first() instead of get.– mistiru
Nov 14 '18 at 17:05
As the statement says, "Explicit is better than implicit". To me, seeing
filter means "it can return multiple values", and get means "it should return one value". So I find strange doing filter().first() instead of get.– mistiru
Nov 14 '18 at 17:05
@mistiru I don't disagree, given the uniqueness of
code. Your solution is principled and perfectly valid. I would, however, consider my approach a bit more readable and tidy as all invalid cases are handled and detected in the same way (if).– schwobaseggl
Nov 14 '18 at 17:22
@mistiru I don't disagree, given the uniqueness of
code. Your solution is principled and perfectly valid. I would, however, consider my approach a bit more readable and tidy as all invalid cases are handled and detected in the same way (if).– schwobaseggl
Nov 14 '18 at 17:22
add a comment |
1
I would have written the code this way:
def clean_code(self):
input_code = self.cleaned_data['code']
try:
discount_code = self.event.discounts.get(code=input_code)
except Discount.DoesNotExist: # suppose your model is named Discount
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
answered Nov 14 '18 at 16:58
mistirumistiru
440113
add a comment |
1
I would have written the code this way:
def clean_code(self):
input_code = self.cleaned_data['code']
try:
discount_code = self.event.discounts.get(code=input_code)
except Discount.DoesNotExist: # suppose your model is named Discount
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
answered Nov 14 '18 at 16:58
mistirumistiru
440113
add a comment |
1
1
1
I would have written the code this way:
def clean_code(self):
input_code = self.cleaned_data['code']
try:
discount_code = self.event.discounts.get(code=input_code)
except Discount.DoesNotExist: # suppose your model is named Discount
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
answered Nov 14 '18 at 16:58
mistirumistiru
440113
I would have written the code this way:
def clean_code(self):
input_code = self.cleaned_data['code']
try:
discount_code = self.event.discounts.get(code=input_code)
except Discount.DoesNotExist: # suppose your model is named Discount
raise forms.ValidationError(_("The discount code couldn't be found."),
code='code_exists')
if not discount_code.is_active():
raise forms.ValidationError(_("This discount code is not available anymore."),
code='code_not_active')
return input_code
answered Nov 14 '18 at 16:58
mistirumistiru
440113
answered Nov 14 '18 at 16:58
mistirumistiru
440113
answered Nov 14 '18 at 16:58
mistirumistiru
440113
answered Nov 14 '18 at 16:58
mistirumistiru
440113
440113
add a comment |
add a comment |
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