Django 数据库进阶操作

# 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 # obj = models.Tb1(c1='xx', c2='oo')
# obj.save() # 查
#
# models.Tb1.objects.get(id=123) # 获取单条数据，不存在则报错（不建议）
# models.Tb1.objects.all() # 获取全部
# models.Tb1.objects.filter(name='seven') # 获取指定条件的数据
# models.Tb1.objects.exclude(name='seven') # 获取指定条件的数据 # 删
#
# models.Tb1.objects.filter(name='seven').delete() # 删除指定条件的数据 # 改
# models.Tb1.objects.filter(name='seven').update(gender='0') # 将指定条件的数据更新，均支持 **kwargs
# obj = models.Tb1.objects.get(id=1)
# obj.c1 = '111'
# obj.save()

# 获取个数
#
# models.Tb1.objects.filter(name='seven').count() # 大于，小于
#
# models.Tb1.objects.filter(id__gt=1) # 获取id大于1的值
# models.Tb1.objects.filter(id__gte=1) # 获取id大于等于1的值
# models.Tb1.objects.filter(id__lt=10) # 获取id小于10的值
# models.Tb1.objects.filter(id__lte=10) # 获取id小于10的值
# models.Tb1.objects.filter(id__lt=10, id__gt=1) # 获取id大于1 且 小于10的值 # in
#
# 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 # isnull
# Entry.objects.filter(pub_date__isnull=True) # contains（类似于数据库中like的语法）
#
# models.Tb1.objects.filter(name__contains="ven")
# models.Tb1.objects.filter(name__icontains="ven") # icontains大小写不敏感
# models.Tb1.objects.exclude(name__icontains="ven") # range
#
# models.Tb1.objects.filter(id__range=[1, 2]) # 范围bettwen and # 其他类似
# 以什么开始，以什么结束，和上面一样带i的是大小写不敏感
# startswith，istartswith, endswith, iendswith, # order by
# 排序
# models.Tb1.objects.filter(name='seven').order_by('id') # asc
# models.Tb1.objects.filter(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] # regex正则匹配，iregex 不区分大小写
#
# Entry.objects.get(title__regex=r'^(An?|The) +')
# Entry.objects.get(title__iregex=r'^(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)

# 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) # Q
#
# 方式一：
# Q(nid__gt=10)
# Q(nid=8) | Q(nid__gt=10)
# Q(Q(nid=8) | Q(nid__gt=10)) & Q(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) # 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()