django orm 操作表

django orm 操作表

1、基本操作

• 增

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','')
obj = models.Tb1(c1='xx', c2='oo')
obj.save()
insert into Tb1 (c1,c2) values ('xx','')

# 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)

• 查

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)

• 删

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

• 改

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

• in

   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'])

• F

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

• Q

    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')