ORM单表查询，跨表查询，分组查询

models.Tb1.objects.filter(id__lt=10, id__gt=1)   # 获取id大于1 且 小于10的值
models.Tb1.objects.filter(id__in=[11, 22, 33])   # 获取id等于11、22、33的数据
models.Tb1.objects.exclude(id__in=[11, 22, 33])  # not in 
models.Tb1.objects.filter(name__contains="ven")  # 获取name字段包含"ven"的
models.Tb1.objects.filter(name__icontains="ven") # icontains大小写不敏感
models.Tb1.objects.filter(id__range=[1, 3])      # id范围是1到3的，等价于SQL的bettwen and
类似的还有：startswith，istartswith, endswith, iendswith　
date字段还可以：
models.Class.objects.filter(first_day__year=2017)

#获取id大于1且小于10的值
print(models.Book.objects.filter(id__lt=10,id__gt=1))
# 查询 id 在 [1, 4, 5, 7]中的结果
print(models.Book.objects.filter(id__in=[1,4,5,7]))
# contains 字段包含指定值的
print(models.Book.objects.filter(title__contains="小单"))
# icontains 忽略大小写包含指定值
print(models.Book.objects.filter(title__icontains="NI"))
# 判断id值在 哪个区间的 SQL语句中的between and  1<= <=3
print(models.Book.objects.filter(id__range=[1,3]))
# 日期和时间字段还可以有以下写法
ret = models.Person.objects.filter(birthday__year=2000)
ret = models.Person.objects.filter(birthday__year=2000, birthday__month=5)

                        跨表查询操作                  

class Author(models.Model):
    nid = models.AutoField(primary_key=True)
    name=models.CharField( max_length=32)
    age=models.IntegerField()
    # 与AuthorDetail建立一对一的关系
    authorDetail=models.OneToOneField(to="AuthorDetail",on_delete=models.CASCADE)

class AuthorDetail(models.Model):
    nid = models.AutoField(primary_key=True)
    birthday=models.DateField()
    telephone=models.BigIntegerField()
    addr=models.CharField( max_length=64)

class Publish(models.Model):
    nid = models.AutoField(primary_key=True)
    name=models.CharField( max_length=32)
    city=models.CharField( max_length=32)
    email=models.EmailField()
class Book(models.Model):
    nid = models.AutoField(primary_key=True)
    title = models.CharField( max_length=32)
    publishDate=models.DateField()
    price=models.DecimalField(max_digits=5,decimal_places=2)
    # 与Publish建立一对多的关系,外键字段建立在多的一方
    publish=models.ForeignKey(to="Publish",to_field="nid",on_delete=models.CASCADE)
    # 与Author表建立多对多的关系,ManyToManyField可以建在两个模型中的任意一个，自动创建第三张表
    authors=models.ManyToManyField(to='Author',)

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