Django--models表操作

需求

models对表的增删改查

知识点

1、基础操作

1.1  增

方法一

models.Tb1.objects.create(c1 = 'xx' , c2 = 'oo' )  #增加一条数据

dic = { 'c1' : 'xx' , 'c2' : 'oo' }
models.Tb1.objects.creat( * * dic)     #可以接受字典类型数据 **kwargs

form提交的数据就是字典类型，可以直接当做参数**dic传给models增加数据。

方法二

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

1.2  查

models.Tb1.objects.get( id = 123 )         # 获取单条数据，不存在则报错（不建议使用）

models.Tb1.objects. all ()    # 获取全部，它是一个Django的查询对象；取第一条.first()；取列成字典.values('username')；取列成列表.value_list()

models.Tb1.objects. filter (name = 'seven' ) # 获取指定条件的数据

1.3  删

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

1.4  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()                    # 修改单条数据,不常用

2、进阶操作

2.1  获取个数

models.Tb1.objects. filter (name = 'seven' ).count()

2.2  大于，小于

models.Tb1.objects. filter (id__gt = 1 )              # 获取id大于1的值，（两个双下划线）
models.Tb1.objects. filter (id__lt = 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

2.3  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

2.4  contains

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" )

2.5  range

models.Tb1.objects.filter(id__range=[ 1 , 2 ])      # 范围bettwen and

2.6  其他类似

startswith，istartswith, endswith, iendswith,

2.7  order by

models.Tb1.objects. filter (name = 'seven' ).order_by( 'id' )    # asc，从小到大排列
models.Tb1.objects. filter (name = 'seven' ).order_by( '-id' )   # desc，从大到小排列

2.8  limit 、offset

models.Tb1.objects. all ()[ 10 : 20 ]    #分页用

2.9  group by

from django.db.models import Count, Min, Max, Sum    #个数，最小，最大，求和
models.Tb1.objects.filter(c1= 1 ).values( 'id' ).annotate(c=Count( 'num' ))     #annotate=grounp by，比如id为1的num列的个数
    #SELECT "app01_tb1"."id", COUNT("app01_tb1"."num") AS "c" FROM "app01_tb1" WHERE "app01_tb1"."c1" = 1 GROUP BY "app01_tb1"."id"

详细

1、增

models.py

class SimpleModel(models.Model):
    username = models.CharField(max_length = 64 )
    password = models.CharField(max_length = 64 )

views.py

def index(request):
    dic = { "username" : "user1" , "password" : "123" }
    models.SimpleModel.objects.create( * * dic)
   obj = HomeForm.ImportForm(request.POST)
   return render(request, 'home/index.html' ,{ 'obj' :obj})

2、查

def index(request):
    ret = models.SimpleModel.objects. all ()
    print ret   #[<SimpleModel: SimpleModel object>, ]对象的列表
    print type (ret)     #<class 'django.db.models.query.QuerySet'>
    print ret.query     #SELECT "id", "username","password" FROM "app01_simplemodel"
    print models.SimpleModel.objects. all ().values( "username" )
        #[{'username': u'user1'}, {'username': u'user2'}, {'username': u'user3'}]
    print models.SimpleModel.objects. all ().values_list( "id" , "username" )
        #[(1, u'user1'), (2, u'user2'), (3, u'user3')]
        #正是form--select的格式
    obj = HomeForm.ImportForm(request.POST)
    return render(request, 'home/index.html' ,{ 'obj' :obj})

来自为知笔记(Wiz)