django Q条件

#q条件
from django.db.models import Q
q = Q(name__startswith="p") | Q(name__startswith="l")  #or条件
v =models.Book.objects.filter(q).values("name")
print(v)

#匹配

models.Book.objects.filter(name__startswith="p")  #匹配name字段中以p开头的有哪些

#聚合

from django.db.models import Avg,Max,Min,Sum,Count #orm聚合  导入聚合模块

示例
#model.py

class Book(models.Model):
    name = models.CharField(max_length=128,unique=True)
    price = models.PositiveSmallIntegerField()
    authors = models.ManyToManyField("Author")
    publisher = models.ForeignKey("Publisher")
    pub_date = models.DateField()
    def __str__(self):
        return self.name

class Author(models.Model):
    name = models.CharField(max_length=128)
    email = models.EmailField(unique=True)
    def __str__(self):
        return  self.name

class Publisher(models.Model):
    name = models.CharField(max_length=128,unique=True)
    website = models.URLField(unique=True)
    def __str__(self):
        return self.name


#给多对多表添加数据
#v = models.Book.objects.create(name="linux",price=33,publisher_id=2,pub_date="2017-06-02")
#v.authors.add(1,2)
#v.save()