Python 如何在django中使用查找和条件相关插入执行插入？
我试图通过django优化大型数据集的数据库插入。 这里有一个简单的示例模型，足以说明我面临的问题Python 如何在django中使用查找和条件相关插入执行插入？,python,sql,django,database,sqlite,Python,Sql,Django,Database,Sqlite,我试图通过django优化大型数据集的数据库插入。 这里有一个简单的示例模型，足以说明我面临的问题 class School(models.Model): name = models.CharField(max_length=32) postcode = models.CharField(max_length=8) class Student(models.Model): name = models.CharField(max_length=32) school
class School(models.Model):
name = models.CharField(max_length=32)
postcode = models.CharField(max_length=8)
class Student(models.Model):
name = models.CharField(max_length=32)
school = models.ForeignKey(School)
last_updated = models.DateTimeField(blank=True, null=True)
first_registered = models.DateTimeField(blank=True, null=True)
school = app.models.School.objects.get_or_create(name='School 1', postcode='AB12 3CD')
student = app.models.Student.objects.create(name='Student 1', school=school[0])
- 学校条目每次都需要数据库往返
- 比赛条件是可能的
- 有一个学校和学生数据的主列表
- 学生和学校名单每天更新
- 数据没有特定的顺序
- 以前的数据可能存在，但也可以删除
- 以前的数据也可能会更新（超出此问题的范围）
- 如果删除，则表示该学生不再是学生
# See if the student already exists and is assigned to the school in the data set.
# If it does exist, get the database to update the last updated date and the first registration dates if needs be.
#
# Note: These updates are necessary as it is possible that data is imported in non-chronological order.
updated_fields = app.models.Student.objects.filter(
name=data['student_name'],
school__name=data['school_name'],
school__postcode=data['school_postcode'],
).update(
last_updated=Case(
When(last_updated__lt=data['last_updated'], then=data['last_updated']),
default=F('last_updated')
),
first_registered=Case(
When(first_registered_gt=data['first_registered'], then=data['first_registered']),
default=F('first_registered')
)
)
for entry in data:
school = app.models.School.objects.get_or_create(name=entry['school_name'], postcode=entry['school_postcode'])
student = app.models.Student.objects.create(name=data['student_name'], school=school[0])