首页 > > 网络编程 > 其它 >

django orm 操作表

2018-12-24 09:06:11来源：博客园阅读 ()

django orm 操作表

1、基本操作

models.Tb1.objects.create(c1='xx', c2='oo')  增加一条数据，可以接受字典类型数据 **kwargs
insert into Tb1 (c1,c2) values ('xx','00')
obj = models.Tb1(c1='xx', c2='oo')
obj.save()
insert into Tb1 (c1,c2) values ('xx','00')

# get_or_create()  如果纯在则获取，否者创建
obj, created = models.UserInfo.objects.get_or_create(name='summer1',
                                                       defaults={'age':123,'pwd':'ab456'})
# 先根据条件去查，如果存在name='summer1'，则后面的default无效不执行。
print(obj,created) # created 为True或False

# update_or_create() 如果存在，则更新，否则，创建
obj, created = models.UserInfo.objects.update_or_create(name='summer1',
                                                       defaults={'age':123,'pwd':'ab456'})

print(obj,created)

models.Tb1.objects.get(id=123)         # 获取单条数据，不存在则报错（不建议）
select * from Tb1 where id=123 limit 1
models.Tb1.objects.all()               # 获取全部
select * from Tb1
models.Tb1.objects.filter(name='seven') # 获取指定条件的数据
select * from Tb1 where name='seven'

# exists()
# 检查查询结果是否存在，返回True或False
result = models.UserInfo.objects.filter(id=1111).exists()
print(result)

models.Tb1.objects.filter(name='seven').delete() # 删除指定条件的数据
delete from Tb1 where name='seven'

models.Tb1.objects.filter(name='seven').update(gender='0')  # 将指定条件的数据更新，均支持 **kwargs
update Tb1 set gender='0' where name='seven'
obj = models.Tb1.objects.get(id=1)
obj.c1 = '111'
obj.save()                                                 # 修改单条数据
update Tb1 set c1 = '111' where id=1

2、进阶操作（了不起的双下划线）

利用双下划线将字段和对应的操作连接起来

获取个数

  models.Tb1.objects.filter(name='seven').count()
  select count(*) from Tb1 where name='seven'

大于，小于

  models.Tb1.objects.filter(id__gt=1)              # 获取id大于1的值
  select * from Tb1 where id>1
  models.Tb1.objects.filter(id__gte=1)              # 获取id大于等于1的值
  select * from Tb1 where id>=1
  models.Tb1.objects.filter(id__lt=10)             # 获取id小于10的值
  select * from Tb1 where id<10
  models.Tb1.objects.filter(id__lte=10)             # 获取id小于等于10的值
  select * from Tb1 where id<=10
  models.Tb1.objects.filter(id__lt=10, id__gt=1)   # 获取id大于1 且 小于10的值
  select * from Tb1 where id<10 and id>1

 models.Tb1.objects.filter(id__in=[11, 22, 33])   # 获取id等于11、22、33的数据
  select * from Tb1 where id in (11, 22, 33)
  models.Tb1.objects.exclude(id__in=[11, 22, 33])  # not in
  select * from Tb1 where id not in (11, 22, 33)

isnull

 Entry.objects.filter(pub_date__isnull=True)
  select * from Tb1 where pub_date is null

contains

models.Tb1.objects.filter(name__contains="ven")
  select * from Tb1 where name like binary '%ven%'
  models.Tb1.objects.filter(name__icontains="ven") # icontains大小写不敏感
  select * from Tb1 where name like  '%ven%'
  models.Tb1.objects.exclude(name__icontains="ven")
  select * from Tb1 where name not like '%ven%'

range

 models.Tb1.objects.filter(id__range=[1, 2])   # 范围bettwen and
  select * from Tb1 where id bettwen 1 and 2

其他类似

startswith，istartswith, endswith, iendswith,
  startswith select * from Tb1 where name like  'ven%'
  endswith  select * from Tb1 where name like  '%ven'

order by

 models.Tb1.objects.filter(name='seven').order_by('id')    # asc
  select * from Tb1 where name='seven' order by id asc
  models.Tb1.objects.filter(name='seven').order_by('-id')   # desc
  select * from Tb1 where name='seven' order by id desc

group by

  from django.db.models import Count, Min, Max, Sum
  models.Tb1.objects.filter(c1=1).values('id').annotate(c=Count('num'))
  SELECT "app01_tb1"."id", COUNT("app01_tb1"."num") AS "c" FROM "app01_tb1" WHERE "app01_tb1"."c1" = 1 GROUP BY "app01_tb1"."id"

limit 、offset

  models.Tb1.objects.all()[10:20]
  select * from Tb1 limit 10,20

regex正则匹配，iregex 不区分大小写

  Entry.objects.get(title__regex=r'^(An?|The) +')
  select * from Entry where title regexp binary "^(An?|The) +"
  Entry.objects.get(title__iregex=r'^(an?|the) +')
  select * from Entry where title regexp "^(An?|The) +"

date

  Entry.objects.filter(pub_date__date=datetime.date(2005, 1, 1))
  Entry.objects.filter(pub_date__date__gt=datetime.date(2005, 1, 1))

year

  Entry.objects.filter(pub_date__year=2005)
  Entry.objects.filter(pub_date__year__gte=2005)

month

  Entry.objects.filter(pub_date__month=12)
  Entry.objects.filter(pub_date__month__gte=6)

day

  Entry.objects.filter(pub_date__day=3)
  Entry.objects.filter(pub_date__day__gte=3)

week_day

  Entry.objects.filter(pub_date__week_day=2)
  Entry.objects.filter(pub_date__week_day__gte=2)

hour

  Event.objects.filter(timestamp__hour=23)
  Event.objects.filter(time__hour=5)
  Event.objects.filter(timestamp__hour__gte=12)

minute

  Event.objects.filter(timestamp__minute=29)
  Event.objects.filter(time__minute=46)
  Event.objects.filter(timestamp__minute__gte=29)

second

  Event.objects.filter(timestamp__second=31)
  Event.objects.filter(time__second=2)
  Event.objects.filter(timestamp__second__gte=31)

3、其他操作

extra

 extra(self, select=None, where=None, params=None, tables=None, order_by=None, select_params=None)
 Entry.objects.extra(select={'new_id': "select col from sometable where othercol > %s"}, select_params=(1,))
 Entry.objects.extra(where=['headline=%s'], params=['Lennon'])
 Entry.objects.extra(where=["foo='a' OR bar = 'a'", "baz = 'a'"])
 Entry.objects.extra(select={'new_id': "select id from tb where id > %s"}, select_params=(1,), order_by=['-nid'])

  from django.db.models import F
  models.Tb1.objects.update(num=F('num')+1)
  update Tb1 set num=num+1

  from django.db.models import Q
  方式一：
  Q(nid__gt=10)
  Q(nid=8) | Q(nid__gt=10)
  select * from table where nid=8 or nid>10
  Q(Q(nid=8) | Q(nid__gt=10)) & Q(caption='root')
  select * from Tb1 where (nid=8 or nid>10) and caption='root'
  方式二：
  con = Q()
  q1 = Q()
  q1.connector = 'OR'
  q1.children.append(('id', 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))
  con.add(q1, 'AND')
  con.add(q2, 'AND')

  models.Tb1.objects.filter(con)
  select * from Tb1 where ( id=1 or id=10 or id=9 ) and ( c1=1 or c1=10 or c1=9 )

执行原生SQL

  from django.db import connection, connections
  cursor = connection.cursor()  # cursor = connections['default'].cursor()
  cursor.execute("""SELECT * from auth_user where id = %s""", [1])
  row = cursor.fetchone()

4、连表操作（了不起的双下划线）

利用双下划线和 _set 将表之间的操作连接起来

表结构实例

class UserProfile(models.Model):
    user_info = models.OneToOneField('UserInfo')
    username = models.CharField(max_length=64)
    password = models.CharField(max_length=64)

    def __str__(self):
        return self.username


class UserInfo(models.Model):
    user_type_choice = (
        (0, '普通用户'),
        (1, '高级用户'),
    )
    user_type = models.IntegerField(choices=user_type_choice)
    name = models.CharField(max_length=32)
    email = models.CharField(max_length=32)
    address = models.CharField(max_length=128)

    def __str__(self):
        return self.name


class UserGroup(models.Model):

    caption = models.CharField(max_length=64)

    user_info = models.ManyToManyField('UserInfo')

    def __str__(self):
        return self.caption


class Host(models.Model):
    hostname = models.CharField(max_length=64)
    ip = models.GenericIPAddressField()
    user_group = models.ForeignKey('UserGroup')

    def __str__(self):
        return self.hostname

一对一操作

  user_info_obj = models.UserInfo.objects.filter(id=1).first()
  print (user_info_obj.user_type)
  select user_type drom UserInfo where id=1 limit 1
  print (user_info_obj.get_user_type_display())
  print (user_info_obj.userprofile.password)
  select userprofile.password from userprofile,UserInfo where UserInfo.id=1 and UserInfo.id=userprofile.user_info
  
  user_info_obj = models.UserInfo.objects.filter(id=1).values('email', 'userprofile__username').first()
  select email, userprofile.username from UserInfo,userprofile where UserInfo.id=1 and UserInfo.id=userprofile.user_info
  print (user_info_obj.keys())
  print (user_info_obj.values())

一对多

  类似一对一
  1、搜索条件使用 __ 连接
  2、获取值时使用 .    连接

多对多操作

  user_info_obj = models.UserInfo.objects.get(name=u'武沛齐')
  user_info_objs = models.UserInfo.objects.all()
  
  group_obj = models.UserGroup.objects.get(caption='CEO')
  group_objs = models.UserGroup.objects.all()
  
  # 添加数据
  group_obj.user_info.add(user_info_obj)
  group_obj.user_info.add(*user_info_objs)
  
  # 删除数据
  group_obj.user_info.remove(user_info_obj)
  group_obj.user_info.remove(*user_info_objs)
  
  # 添加数据
  user_info_obj.usergroup_set.add(group_obj)
  user_info_obj.usergroup_set.add(*group_objs)
  
  # 删除数据
  user_info_obj.usergroup_set.remove(group_obj)
  user_info_obj.usergroup_set.remove(*group_objs)
  
  # 获取数据
  print group_obj.user_info.all()
  print group_obj.user_info.all().filter(id=1)
  
  # 获取数据
  print user_info_obj.usergroup_set.all()
  print user_info_obj.usergroup_set.all().filter(caption='CEO')
  print user_info_obj.usergroup_set.all().filter(caption='DBA')