链接两个字段/关系的Django“ Model.objects.create”

如何解决链接两个字段/关系的Django“ Model.objects.create”

如果是错的或误导性的，请稍稍纠正我，谢谢。

我是Django Python的新手。我正在使用Django 3.1.1。

我的问题是关于"Model".objects.create()的问题，我将其与ajax一起用于在Logger模型中保存或创建数据。

问题：如何使用Logger.userprofile将UserProfile.user链接到Logger.objects.create()或链接这两个字段的下一步是什么？

我的UserProfile模型已经通过User链接到OneToOneField模型，但是正在使用form.save()保存数据，并且成功。以下是我通过阅读大量教程到目前为止构建的内容。

这已经在起作用，并且正在我的模型中创建数据，我只需要在UserProfile和Logger之间添加链接，以便于识别创建的日志。

在Logger模型中通过qrcode扫描创建日志。

Views.py

def processQRCode(request):

    if request.method == 'POST':
            qrcoderes = request.POST['qrcoderes']
            logged_in = request.POST['logged_in']
            logged_in_location = request.POST['logged_in_location']

            Logger.objects.create(
                qrcode_uuid = qrcoderes,#edited from qrcode_uuid to qrcoderes to distinguish the two variables.
                logged_in = logged_in,logged_in_location = logged_in_location 
            )

    return HttpResponse('Success!')

Models.py

UserProfile模型

class UserProfile(models.Model):

    GENDER = (
        ('Male','Male'),('Female','Female'),)

    user = models.OneToOneField(User,related_name='userprofile',null=True,on_delete=models.SET_NULL)

    qrcode_uuid = models.UUIDField(unique=True,default=uuid4)
    qr_code = models.ImageField(upload_to='qr_codes',blank=True)

    firstName = models.CharField(max_length=200)
    middleName = models.CharField(max_length=200)
    lastName = models.CharField(max_length=200)
    gender = models.CharField(max_length=6,choices=GENDER)
    birthdate = models.DateField(max_length=200)
    contact = models.CharField(max_length=200)
    agency = models.CharField(max_length=200) 
    deptSec = models.CharField(max_length=200)
    designation = models.CharField(max_length=200)
    streetHouse = models.CharField(max_length=200)
    purok = models.CharField(max_length=200)
    barangay = models.CharField(max_length=200)
    cityMunicipality = models.CharField(max_length=200)
    province = models.CharField(max_length=200)
    date_created = models.DateTimeField(auto_now_add=True)

    class Meta:
        verbose_name_plural = 'User Profile'

    def __str__(self):
        return self.firstName + " " + self.middleName + " " + self.lastName

    def save(self,*args,**kwargs):
        qrcode_img = qrcode.make(self.qrcode_uuid)
        canvas = Image.new('RGB',(370,370),'white')
        draw = ImageDraw.Draw(canvas)
        canvas.paste(qrcode_img)
        fileName = f'qr-code-{self.qrcode_uuid}.png'
        buffer = BytesIO()
        canvas.save(buffer,'PNG')
        self.qr_code.save(fileName,File(buffer),save=False)
        canvas.close()
        super().save(*args,**kwargs)

记录器型号

class Logger(models.Model):
    userprofile = models.OneToOneField(UserProfile,on_delete=models.SET_NULL)

    qrcode_uuid = models.CharField(max_length=200,null=True)
    logged_in = models.CharField(max_length=1,default="1")
    logged_in_location = models.CharField(max_length=200,null=True)
    log_datetime = models.DateTimeField(auto_now_add=True)

    class Meta:
            verbose_name_plural = 'Logger'

    def __str__(self):
            return self.logged_in_location + " " + self.qrcode_uuid

Ajax.js

function processQRCodeDetails(){

$.ajax({
      type:'POST',url: '/processqrcode/',data:{
        qrcoderes: $('#process-qrcoderes').val(),logged_in: $('#logged_in').val(),logged_in_location: $('#logged_in_location').val(),csrfmiddlewaretoken: $('input[name="csrfmiddlewaretoken"]').val()
      },success: function(data){
        $('#staticBackdrop').modal();
        console.log('Success');
      },error: function(data){
        console.log('Error')
      }
    });

}

template.html

<form id="process-qrcoderes-form">
  {% csrf_token %}
  <input class="form-control" type="text" name="process-qrcoderes" id="process-qrcoderes" onchange="processQRCodeDetails(); return false;" autofocus="autofocus">
  <input type="text" name="logged_in" id="logged_in" value="1">
  <input type="text" name="logged_in_location" id="logged_in_location" value="test">
</form>

解决方法

您需要从数据库获取UserProfile并将其传递给创建方法

 def processQRCode(request):
    if request.method == 'POST':
        qrcode_uuid = request.POST['qrcoderes']
        logged_in = request.POST['logged_in']
        logged_in_location = request.POST['logged_in_location']

        # edit: you can get your UserProfile instance by "qrcode_uuid" as well
        # use get_or_create,note that it returns tuple,not instance
        userprofile,created = UserProfile.objects.get_or_create(qrcode_uuid=qrcode_uuid)
 
        if created:
            # some additional actions here for newly created UserProfile,filling some fields may be
            
            # recommended naming convention for class attrs in python is underscore_case,not camelCase
            userprofile.firstName = "John"
            userprofile.save()

        Logger.objects.create(
            qrcode_uuid = qrcode_uuid,logged_in = logged_in,logged_in_location = logged_in_location,userprofile=userprofile
        )

    return HttpResponse('Success!')

,

不小心解决了。

我不知道UUIDField发生了什么，但是不幸的是，幸运的是，当我扫描UserProfile模型下的记录时（其中只有3条记录）使用django admin的“保存并继续编辑”进行编辑的第三条记录，“它的工作原理就像一个魅力！” （大家都称呼它为：D），因此，我继续编辑其他2条记录，它也起作用。

我的主要目标是将id模型的UserProfile插入到Logger模型中，以使用以下语法链接两个模型：

# been trying this syntax for ages now. lol. and it was not the problem.
userprofile_id = UserProfile.objects.get(qrcode_uuid=qrcoderes) 

    #Note: Using the .objects.create() method also works now.
    log = Logger(
            userprofile = userprofile_id,qrcode_uuid = qrcoderes,#edited from qrcode_uuid to qrcoderes to distinguish the two variables.
            logged_in = logged_in,logged_in_location = logged_in_location
        )
    log.save()

注意：这不起作用，它给了我一个错误UserProfile matching query does not exist.，即使使用了shell，它也给了我同样的错误。所以，我想，我的语法就是问题所在，这就是为什么我在这里发布问题。

也许，我会尝试在CharField上使用UUID，如果有所作为或与UUID兼容。