blocks|key|279611|text|您不能在数据库层上创建这种逻辑。在这种情况下，您可以将此逻辑移动到模型的类方法中，以满足干模式。还将模型中的字段设置为可空。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|279612|差不多是这样的：|279613|class+YourClass(models.Model):
++++store_type+=+models.CharField(blank=True,+choices=Storetypes.choices,+max_length=12)
++++api_url+=+models.CharField(blank=True,)
++++access_key+=+models.CharField(blank=True,+max_length=100,+null=True)
++++consumer_key+=+models.CharField(blank=True,+max_length=100,+null=True)
++++consumer_secret+=+models.CharField(blank=True,+max_length=100,+null=True)

++++@classmethod
++++def+save_woo_commerce(cls,+api_url,+consumer_key,+consumer_secret):
++++++++return+YourClass.objects.create(
++++++++++++store_type="woo_commerce",
++++++++++++api_url=api_url,
++++++++++++consumer_key=consumer_key,
++++++++++++consumer_secret=consumer_secret
++++++++)

++++@classmethod
++++def+save_shopify(cls,+api_url,+access_key):
++++++++return+YourClass.objects.create(
++++++++++++store_type="shopify",
++++++++++++access_key=access_key,
++++++++++++api_url=api_url,
++++++++)|code-block|syntax|javascript|279614|这样，您的逻辑仍然连接到模型，并且可以在代码的多个位置重用实例创建。|279615|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

You can't make this type of logic on database layer. For this case you can move this logic to a classmathod of the model to satisfy the dry-pattern. Also set the fields to nullable in your model.
Something like so:
<pre><code>class YourClass(models.Model):
 store_type = models.CharField(blank=True, choices=Storetypes.choices, max_length=12)
 api_url = models.CharField(blank=True,)
 access_key = models.CharField(blank=True, max_length=100, null=True)
 consumer_key = models.CharField(blank=True, max_length=100, null=True)
 consumer_secret = models.CharField(blank=True, max_length=100, null=True)

 @classmethod
 def save_woo_commerce(cls, api_url, consumer_key, consumer_secret):
 return YourClass.objects.create(
 store_type=&quot;woo_commerce&quot;,
 api_url=api_url,
 consumer_key=consumer_key,
 consumer_secret=consumer_secret
 )

 @classmethod
 def save_shopify(cls, api_url, access_key):
 return YourClass.objects.create(
 store_type=&quot;shopify&quot;,
 access_key=access_key,
 api_url=api_url,
 )
</code></pre>
With that your logic is still connected to the model and you can reuse instance creation on multiple places of your code.

blocks|key|2390201|text|在某种程度上，这些字段将成为输入。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2390202|如果它们是通过表单出现的，那么就需要使用clean方法为无效的组合生成错误，或者在视图级别进行检查。我发现在基于类的视图(基于FormView)中经常使用的模式如下所示。关键点:将有效表单转换为无效表单的form.add_error，以及向用户展示需要修复的内容的return+self.form_invalid(form)。|offset|length|style|CODE|2390203|def+form_valid(+self,+form)
++++store_type+=+form.Cleaned_data['store_type']
++++api_url+=+form.cleaned_data['+...+']
++++...
++++#+now,+further+checks
++++...
++++errors+=+False
++++if+store_type+==+SHOPIFY+or+store_type+==+SHOPPER:
+++++++++#+consumer_key+and+consumer+secret+not+required
+++++++++consumer_key+=+consumer_secret+=+''
+++++++++#+but+presumably,+api_url+and+access_key+are+mandatory
+++++++++if+api_url+==+'':
+++++++++++++#+get+human+representation+of+store_type
+++++++++++++human_store_type+=+...
+++++++++++++form.add_error('api_url',+f'API+Url+is+required+whenever+store+type+is+"{human_store_type}"'+)+
+++++++++++++errors+=+True
+++++++++if+access_key+==+'':
+++++++++++++...+#+similar,+but+add+error+to+access_Key+field

+++++++++#+maybe+validate+that+the+api_url+and+access_key+actually+work
+++++++++#+and+add+an+error+if+they+don't+work+together?
+++++++++if+not+check_valid(+api_url,+access_key):
+++++++++++++errors+=+True
+++++++++++++form.add_error(+None,+'api_url+and+access_key+do+not+work+with+each+other')+#+non-field+error

+++++++++if+errors:
+++++++++++++return+self.form_invalid(+form)

++++elif+store_type+==+...
++++++++...

++++#+OK+we+have+a+completely+valid+set+of+inputs
++++#+get+the+object+(if+its+a+ModelForm)
++++store++=+form.save(+commit+=+False)
++++store.api_url+=+api_url
++++...+#+and+the+other+fields+we+extra-validated
++++store.save()

++++return+redirect(+...)|code-block|syntax|javascript|2390204|如果任何强制字段为空，则可以对对象上的save方法进行子类化，以导致异常，但这可能会带来比其价值更大的麻烦。如果有一个或几个视图可以设置这些字段，那么检查那里。有时，保存一个不完整的对象甚至是有用的:给它一个布尔is_complete字段。例如，人工主管可能需要授权添加一个新的商店。|2390205|entityMap^0|0|K|5|2U|E|3O|U|0|0|J|4|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]|$D|U|E|V|F|G]|$D|W|E|X|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|Y|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|Z|8|@$D|10|E|11|F|G]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|P|$]]

At some point those fields are going to be inputs.
If they come in through a form, it's a matter of using a <code>clean</code> method that generates errors for invalid combinations, or checking at the view level. A pattern I have found myself using quite often with class-based views (based on FormView) is like the following. Key points: <code>form.add_error</code> to convert a valid form into an invalid one, and <code>return self.form_invalid(form)</code> to show the user what needs to be fixed.
<pre><code>def form_valid( self, form)
 store_type = form.Cleaned_data['store_type']
 api_url = form.cleaned_data[' ... ']
 ...
 # now, further checks
 ...
 errors = False
 if store_type == SHOPIFY or store_type == SHOPPER:
 # consumer_key and consumer secret not required
 consumer_key = consumer_secret = ''
 # but presumably, api_url and access_key are mandatory
 if api_url == '':
 # get human representation of store_type
 human_store_type = ...
 form.add_error('api_url', f'API Url is required whenever store type is &quot;{human_store_type}&quot;' ) 
 errors = True
 if access_key == '':
 ... # similar, but add error to access_Key field

 # maybe validate that the api_url and access_key actually work
 # and add an error if they don't work together?
 if not check_valid( api_url, access_key):
 errors = True
 form.add_error( None, 'api_url and access_key do not work with each other') # non-field error

 if errors:
 return self.form_invalid( form)

 elif store_type == ...
 ...

 # OK we have a completely valid set of inputs
 # get the object (if its a ModelForm)
 store = form.save( commit = False)
 store.api_url = api_url
 ... # and the other fields we extra-validated
 store.save()

 return redirect( ...)
</code></pre>
It's possible to subclass the <code>save</code> method on your object to cause an exception if any mandatory fields are blank, but this can be more trouble than its worth. If there is one or few views through which these fields can be set, then check there. Sometimes, it's even useful to save an incomplete object: give it a Boolean is_complete field. For example, it may be necessary for a human supervisor to authorize the addition of a new store.

I want to add these fields to my Store Model, but i wanna include logic that if Let's say WooCoomerce was chosen as a StoreType, i want Access_Token not to be Required. Also when i Choose either Shopify/Shopper i want Consumer_key and Consumer_secret not to be required. Do you have any idea how to get around that?
<pre><code> StoreType = models.CharField(blank=True, choices=Storetypes.choices, max_length=12)
 Api_Url = models.CharField(blank=True)
 Access_Key = models.CharField(blank=True, max_length=100)
 Consumer_Key = models.CharField(blank=True, max_length=100)
 Consumer_Secret = models.CharField(blank=True, max_length=100)
</code></pre>

If statement in Django Model Fields

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我想将这些字段添加到我的存储模型中，但我想包含这样的逻辑:如果我们假设WooCoomerce被选为StoreType，我希望不需要Access_Token。此外，当我选择Shopify/Shopper时，我希望不需要Consumer_key和Consumer_secret。你知道怎么绕过它吗？    StoreType...

问Django模型字段中的If语句
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