ORM-数据处理

models文件下

class UserType(models.Model):
    title = models.CharField(max_length=32)

class User(models.Model):
    name = models.CharField(max_length=32)
    age = models.IntegerField()
    ut = models.ForeignKey('UserType', on_delete=models.CASCADE)

view文件下

def test(request):
# 创建数据
# models.UserType.objects.create(title='普通用户')
# models.UserType.objects.create(title='二逼用户')
# models.UserType.objects.create(title='牛逼用户')

# models.UserInfo.objects.create(name='方少伟',age=18,ut_id=1)
# models.UserInfo.objects.create(name='由秦兵',age=18,ut_id=2)
# models.UserInfo.objects.create(name='刘庚',age=18,ut_id=2)
# models.UserInfo.objects.create(name='陈涛',age=18,ut_id=3)
# models.UserInfo.objects.create(name='王者',age=18,ut_id=3)
# models.UserInfo.objects.create(name='杨涵',age=18,ut_id=1)

# 获取
# QuerySet[obj,obj,obj]
# result = models.UserInfo.objects.all()
# for obj in result:
# print(obj.name,obj.age,obj.ut_id,obj.ut.title)

# UserInfo，ut是FK字段 - 正向操作 PS: 一个用户只有一个用户类型
# obj = models.UserInfo.objects.all().first()
# print(obj.name,obj.age,obj.ut.title)

# UserType, 表名小写_set.all() - 反向操作 PS: 一个用户类型下可以有很多用户
# obj = models.UserType.objects.all().first()
# print('用户类型',obj.id,obj.title)
# for row in obj.userinfo_set.all():
# print(row.name,row.age)

# result = models.UserType.objects.all()
# for item in result:
# print(item.title,item.userinfo_set.filter(name='xx'))

跨表

正：

1. q = UserInfo.objects.all().first()
q.ug.title

2.
UserInfo.objects.values('nid','ug_id')
UserInfo.objects.values('nid','ug_id','ug__title')

3. UserInfo.objects.values_list('nid','ug_id','ug__title')
反：
1. 小写的表名_set
obj = UserGroup.objects.all().first()
result = obj.userinfo_set.all() [userinfo对象,userinfo对象,]

2. 小写的表名
v = UserGroup.objects.values('id','title')
v = UserGroup.objects.values('id','title','小写的表名称')
v = UserGroup.objects.values('id','title','小写的表名称__age')

3. 小写的表名
v = UserGroup.objects.values_list('id','title')
v = UserGroup.objects.values_list('id','title','小写的表名称')
v = UserGroup.objects.values_list('id','title','小写的表名称__age')

PS: 前面的所有数据都会显示

- 其他：
UserInfo.objects.all()
UserInfo.objects.filter(id=1,id=2)
UserInfo.objects.all().first()
UserInfo.objects.all().count()
UserInfo.objects.all().update()
UserInfo.objects.all().delete()
UserInfo.objects.all()[1:19]
跨表：
正向：
xxxx.filter(ut__title='超级用户').values('id','name','ut__title')
反向：
xxxx.filter(表名称__title='超级用户').values('id','name','表名称__title')

return HttpResponse('...')

1. Django ORM操作
# 1.增删改查
# 2. 一般：
# models.UserInfo.objects.filter(id__gt=1)
# models.UserInfo.objects.filter(id__lt=1)
# models.UserInfo.objects.filter(id__lte=1)
# models.UserInfo.objects.filter(id__gte=1)
# models.UserInfo.objects.filter(id__in=[1,2,3])
# models.UserInfo.objects.filter(id__range=[1,2])
# models.UserInfo.objects.filter(name__startswith='xxxx')
# models.UserInfo.objects.filter(name__contains='xxxx')
# models.UserInfo.objects.exclude(id=1)
# 3. 排序
user_list = models.UserInfo.objects.all().order_by('-id','name')

# 4. 分组
from django.db.models import Count,Sum,Max,Min
# v =models.UserInfo.objects.values('ut_id').annotate(xxxx=Count('id'))
# print(v.query)
# v =models.UserInfo.objects.values('ut_id').annotate(xxxx=Count('id')).filter(xxxx__gt=2)
# print(v.query)
# v =models.UserInfo.objects.filter(id__gt=2).values('ut_id').annotate(xxxx=Count('id')).filter(xxxx__gt=2)
# print(v.query)



# 5. F，更新时用于获取原来的值
# from django.db.models import F,Q
# models.UserInfo.objects.all().update(age=F("age")+1)

# 6. Q，用于构造复杂查询条件
# 应用一：
# models.UserInfo.objects.filter(Q(id__gt=1))
# models.UserInfo.objects.filter(Q(id=8) | Q(id=2))
# models.UserInfo.objects.filter(Q(id=8) & Q(id=2))
# 应用二：
# q1 = Q()
# q1.connector = 'OR'
# q1.children.append(('id__gt', 1))
# q1.children.append(('id', 10))
# q1.children.append(('id', 9))
#
#
# q2 = Q()
# q2.connector = 'OR'
# q2.children.append(('c1', 1))
# q2.children.append(('c1', 10))
# q2.children.append(('c1', 9))
#
# q3 = Q()
# q3.connector = 'AND'
# q3.children.append(('id', 1))
# q3.children.append(('id', 2))
# q2.add(q3,'OR')
#
# con = Q()
# con.add(q1, 'AND')
# con.add(q2, 'AND')

# models.UserInfo.objects.filter(con)

# 7. extra, 额外查询条件以及相关表，排序

models.UserInfo.objects.filter(id__gt=1)
models.UserInfo.objects.all()
# id name age ut_id


models.UserInfo.objects.extra(self, select=None, where=None, params=None, tables=None, order_by=None, select_params=None)
# a. 映射
# select
# select_params=None
# select 此处 from 表

# b. 条件
# where=None
# params=None,
# select * from 表 where 此处

# c. 表
# tables
# select * from 表,此处

# c. 排序
# order_by=None
# select * from 表 order by 此处


models.UserInfo.objects.extra(
select={'newid':'select count(1) from app01_usertype where id>%s'},
select_params=[1,],
where = ['age>%s'],
params=[18,],
order_by=['-age'],
tables=['app01_usertype']
)
"""
select
app01_userinfo.id,
(select count(1) from app01_usertype where id>1) as newid
from app01_userinfo,app01_usertype
where
app01_userinfo.age > 18
order by
app01_userinfo.age desc
"""

result = models.UserInfo.objects.filter(id__gt=1).extra(
where=['app01_userinfo.id < %s'],
params=[100,],
tables=['app01_usertype'],
order_by=['-app01_userinfo.id'],
select={'uid':1,'sw':"select count(1) from app01_userinfo"}
)
print(result.query)
# SELECT (1) AS "uid", (select count(1) from app01_userinfo) AS "sw", "app01_userinfo"."id", "app01_userinfo"."name", "app01_userinfo"."age", "app01_userinfo"."ut_id" FROM "app01_userinfo" , "app01_usertype" WHERE ("app01_userinfo"."id" > 1 AND (app01_userinfo.id < 100)) ORDER BY ("app01_userinfo".id) DESC

# 8. 原生SQL语句

from django.db import connection, connections

cursor = connection.cursor() # connection=default数据
cursor = connections['db2'].cursor()

cursor.execute("""SELECT * from auth_user where id = %s""", [1])

row = cursor.fetchone()
row = cursor.fetchall()


- extra
- 原生SQL语句
- raw
result = models.UserInfo.objects.raw('select * from userinfo')
[obj(UserInfo),obj,]
result = models.UserInfo.objects.raw('select id,1 as name,2 as age,4 as ut_id from usertype')
[obj(UserInfo),obj,]

v1 = models.UserInfo.objects.raw('SELECT id,title FROM app01_usertype',translations=name_map)

9. 简单的操作
http://www.cnblogs.com/wupeiqi/articles/6216618.html