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我真的很难更新门票的数量。我的网站(项目)模仿了一个销售音乐事件门票的电子商务网站。
当用户购买门票时,门票数量应该更新。示例:有 100 张门票,已购买 5 张,数据库应显示剩余 95 张。但如果门票低于 0,则应出现警告“此事件不再有门票”。
有人可以帮我实现这个吗?这是我需要做的最后一点,然后我就完成了!干杯。代码:
当我说需要更新时,我指的是 Venue 类中的容量。
模型.py
class Genre(models.Model):
genre = models.CharField(max_length=30, default=None, unique=True)
def __str__(self):
return self.genre
class Meta:
ordering = [ "genre" ]
verbose_name_plural = "genres"
class CardChoices(models.Model):
payment_type = models.CharField(max_length=30, default=None, unique=True)
def __str__(self):
return self.payment_type
class Meta:
ordering = [ "payment_type" ]
verbose_name_plural = "payment types"
### Start
class Venue(models.Model):
"""The 'Venue' model represents a collection of different venues."""
name = models.CharField(max_length=30, default=None)
address = models.CharField(max_length=255, default=None)
capacity = models.PositiveIntegerField(default=0)
website = models.URLField(max_length=50, null=True)
phone_number = models.CharField(validators=[
RegexValidator(regex='^\d{11}$', message='Length has to be 11',
code='Invalid number')], blank=True, null=True, max_length=11)
#phone_number = models.IntegerField(max_length=11, unique=True, validators=[RegexValidator(regex='^\d{10}$', message='Length has to be 11', code='Invalid number')], default=None)
description = models.TextField()
slug = models.SlugField(unique=True, default=None)
# Returns the name of a category
def __str__(self):
return self.name
# Call the slugify method and update the slug field when the name is changed
def save(self, *args, **kwargs):
self.slug = slugify(self.name)
super(Venue, self).save(*args, **kwargs)
class Meta:
# Orders the categories using the name field in ascending order
ordering = [ "name" ]
verbose_name_plural = "venues"
class Artist(models.Model):
"""The 'Artist' model represents a collection of different artists."""
name = models.CharField(max_length=30, default=None)
description = models.CharField(max_length=255)
image = models.ImageField(upload_to='artist/images')
genre = models.ForeignKey('Genre', related_name='genres', default=None)
slug = models.SlugField(unique=True, default=None)
def __str__(self):
return self.name
def save(self, *args, **kwargs):
self.slug = slugify(self.name)
super(Artist, self).save(*args, **kwargs)
class Meta:
ordering = [ "name" ]
verbose_name_plural = "artists"
class Event(models.Model):
"""The 'Event' model represents a collection of different events."""
artists = models.ManyToManyField(Artist)
venue = models.ForeignKey(Venue)
name = models.CharField(max_length=255, default=None)
quantity = models.IntegerField()
price = models.IntegerField() # Needs to be repeated so that django-carton can convert the value (dirty hack needs fixing)
#price = PriceField('Price', currency='GBP', max_digits=10, decimal_places=2)
date = models.DateField()
start_time = models.TimeField()
end_time = models.TimeField()
curfew_time = models.TimeField()
description = models.TextField()
slug = models.SlugField(unique=True, default=None)
def __str__(self):
return self.name
def save(self, *args, **kwargs):
self.slug = slugify(self.name)
super(Event, self).save(*args, **kwargs)
class Meta:
ordering = [ "name" ]
verbose_name_plural = "events"
class UserAccount(models.Model): # needs to be associated with INDIVIDUAL purchases, a user can hold more than one purchase
user = models.OneToOneField(User) # Links user account with a Django User model instance
#event = models.ForeignKey(Event, blank=True)
name = models.CharField(max_length=30)
address = models.CharField(max_length=255)
phone_number = models.IntegerField(max_length=11, unique=True, validators=[RegexValidator(regex='^\d{10}$', message='Length has to be 11', code='Invalid number')])
email = models.EmailField(validators=[validate_email])
def __str__(self):
return self.user.email
class Purchase(models.Model): # needs to be associated with a user account
cash_only = models.BooleanField('Cash only', default=False)
payment_type = models.ForeignKey('CardChoices', related_name='Payment Types')
card_name = models.CharField(max_length=26, default=None, validators=[alphanumeric_RE]) #done
card_number = models.CharField(max_length=19, default=None) # OVERWRITTEN
security_code = models.IntegerField(max_length=3, default=None) # OVERWRITTEN
expiry_date = models.DateField(default=datetime.now) # OVERWRITTEN
date = models.DateField(editable=True, auto_now_add=True, default=datetime.now)
delivery_option = models.BooleanField('Is Collecting Ticket', default=True)
reference_number = models.CharField(max_length=LENGTH, unique=True, default=None)
temp_session_key = models.CharField(null=True, editable=False, max_length=255, default=None)
def __str__(self):
return self.card_name
def save(self, *args, **kwargs): # Thanks to workmajj for providing the logic!
"""
Upon saving, generate a code by randomly picking LENGTH number of
characters from CHARSET and concatenating them. If code has already
been used, repeat until a unique code is found, or fail after trying
MAX_TRIES number of times. (This will work reliably for even modest
values of LENGTH and MAX_TRIES, but do check for the exception.)
Discussion of method: http://stackoverflow.com/questions/2076838/
"""
loop_num = 0
unique = False
while not unique:
if loop_num < MAX_TRIES:
new_code = ''
for i in range(LENGTH):
new_code += CHARSET[randrange(0, len(CHARSET))]
if not Purchase.objects.filter(reference_number=new_code):
self.reference_number = new_code
unique = True
loop_num += 1
else:
raise ValueError("Couldn't generate a unique code.")
super(Purchase, self).save(*args, **kwargs)
class Meta:
ordering = [ "date" ]
Forms.py
class ContactForm(forms.Form):
"""Form for the contact page containing relevant fields and appropriate attributes."""
name = forms.CharField(required=True, max_length=100, label='Name')
email = forms.EmailField(required=True, label='E-mail Address', validators=[validate_email])
subject = forms.CharField(required=True, label='Subject')
query = forms.CharField(required=True, widget=forms.Textarea)
class PurchaseForm(forms.ModelForm):
# Custom fields overwrite the ones in the Purchase model
payment_type = forms.ModelChoiceField(queryset=CardChoices.objects.all())
card_name = forms.CharField(widget=forms.TextInput(attrs={'placeholder': "Card Holder's Name"}))
card_number = CreditCardField(required=True, widget=forms.TextInput(attrs={'placeholder': 'Credit / Debit card number'}))
security_code = VerificationValueField(required=True)
expiry_date = ExpiryDateField(required=True)
DELIVERY_CHOICES = (
(True, 'Collect from Venue'),
(False, 'Print Ticket'),
)
delivery_option = forms.ChoiceField(choices=DELIVERY_CHOICES, widget=forms.RadioSelect())
email_receipt = forms.BooleanField(required=False, label='Tick this box to receive an e-mail receipt')
email = forms.EmailField(required=False, label='E-mail address', validators=[validate_email])
class Meta:
model = Purchase
fields = ("payment_type", "card_name", "card_number", "security_code", "expiry_date", "delivery_option", "email_receipt", "email")
class UserForm(forms.ModelForm):
password = forms.CharField(widget=forms.PasswordInput())
class Meta:
model = User
fields = ("username", "email", "password")
class UserProfileForm(forms.ModelForm):
class Meta:
model = UserAccount
fields = ("name", "address", "phone_number")
最佳答案
在表单验证后,您应该执行以下操作:
try:
with transaction.atomic():
x=get_number_of_tickets
venue=Venue.objects.get(id=5)
venue.capacity -= x
venue.update()
Purchase.save()
except IntegrityError:
raise Error
查看 django transactions 文档以获取更多信息,因为它更完整: https://docs.djangoproject.com/en/1.8/topics/db/transactions/
关于python - 如何更新数量? Django ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30109426/
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