Question

我是Django的新手，为了学习目的，我正在尝试使用linkedn API构建我自己的网站来显示我的个人资料。以下是我的代码示例。看到整个地段：

models.py

class Profile(models.Model):

user = models.ForeignKey(User)
first_name = models.CharField(max_length=20)
last_name = models.CharField(max_length=20)

def __str__(self):
    return self.first_name, self.last_name

class Education(models.Model):

user = models.ForeignKey(User)
school_name =  models.CharField(max_length=100) 
field_study =  models.CharField(max_length=100)
degree =  models.CharField(max_length=100)
start_date =  models.CharField(max_length=20)
end_date =  models.CharField(max_length=20)

和views.py

  profile = Profile(first_name = content['firstName'], 
  last_name = content['lastName'],
  user = request.user)
  profile.save()

#Education model
content_educ = content['educations']['values']
for value in content_educ:
    education = Education(school_name = value['schoolName'],
            user = request.user,
            field_study = value['fieldOfStudy'],
            degree = value['degree'],
            start_date = value['startDate']['year'] ,
            end_date = value['endDate']['year'])
    education.save()

这一切都有效但我的问题是每次检查链接时，代码会再次保存所有对象。理想情况下，在调用.save（）方法时，根据配置文件“更新”字段。我已阅读下一个链接https://docs.djangoproject.com/en/1.7/ref/models/instances/#saving-objects

但是我没有设法使它工作，也许foreigns键没有正确设置所以任何建议/帮助/提示将非常感激。谢谢！

Answer 1

使用update_or_create()方法：

Education.objects.update_or_create(
                   school_name=value['schoolName'],
                   user = request.user,
                   defaults={'field_study': value['fieldOfStudy'],
                             'degree': value['degree'],
                             'start_date': value['startDate']['year'] ,
                             'end_date': value['endDate']['year']})

Answer 2

您遇到的问题是您要在以下行中实例化新的Education实例：

    education = Education(school_name = value['schoolName'],
        user = request.user,
        field_study = value['fieldOfStudy'],
        degree = value['degree'],
        start_date = value['startDate']['year'] ,
        end_date = value['endDate']['year'])

当Django试图保存这些新实例（尚未定义id的实例）时，Django继续并插入记录而不是进行所需的更新。

要进行更新，您可以尝试获取记录，捕获DoesNotExist例外：

try:
    education = Education.objects.get(school_name=value['schoolName'],
        user=request.user,
        field_study=value['fieldOfStudy'],
        degree=value['degree'],
        start_date=value['startDate']['year'],
        end_date=value['endDate']['year'])
except Education.DoesNotExist:
    education = Education(school_name=value['schoolName'],
        user=request.user,
        field_study=value['fieldOfStudy'],
        degree=value['degree'],
        start_date=value['startDate']['year'],
        end_date=value['endDate']['year'])

然后应用您想要/需要的任何更新。

或者您可以使用get_or_create执行相同操作：

(education, created) = Education.objects.get_or_create(school_name=value['schoolName'],
        user=request.user,
        field_study=value['fieldOfStudy'],
        degree=value['degree'],
        start_date=value['startDate']['year'],
        end_date=value['endDate']['year'])

如果您不想按所有这些值查找实例（它们是AND编辑），但想要使用特定值初始化新实例，则应该查找defaults关键字get_or_create。

或者您可以按照catavaran的建议使用update_or_create。

编辑：或者，如果您只想直接更新记录而不获取它（这也适用于多个对象），您可以使用queryset.update

Education.objects.filter(attribute=value, ...).update(attribute2=value2, ...)

在Django上更新数据库中的模型对象

2 个答案: