Django基础
一：FBV&CBV
1.FBV:就是在视图里使用函数处理请求。
from django.conf.urls import url, include # from django.contrib import admin from mytest import views urlpatterns = [ # url(r‘^admin/‘, admin.site.urls), url(r‘^index/‘, views.index), ]
from django.shortcuts import render def index(req): if req.method == ‘POST‘: print(‘method is :‘ + req.method) elif req.method == ‘GET‘: print(‘method is :‘ + req.method) return render(req, ‘index.html‘) 注意此处定义的是函数[def index(req):]
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>index</title> </head> <body> <form action="" method="post"> <input type="text" name="A" /> <input type="submit" name="b" value="提交" /> </form> </body> </html> 上面就是FBV的使用。
2.CBV:就是在视图里使用类处理请求；
from mytest import views urlpatterns = [ # url(r‘^index/‘, views.index), url(r‘^index/‘, views.Index.as_view()), ] 注：url(r'^index/',views.Index.as_view()),是固定用法；
from django.views import View class Index(View): def get(self, req): print(‘method is :‘ + req.method) return render(req, ‘index.html‘) def post(self, req): print(‘method is :‘ + req.method) return render(req, ‘index.html‘) 注：类要继承View ,类中函数名必须小写；
二：Django ORM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() # 修改单条数据
基本操作：
# models.UserInfo.objects.filter(id__gt=1) #获取id大于1的值 # models.UserInfo.objects.filter(id__lt=1) #获取id小于1的值 # models.UserInfo.objects.filter(id__lte=1) #获取id小于等于1的值 # models.UserInfo.objects.filter(id__gte=1) #获取id大于等于1的值 # models.UserInfo.objects.filter(id__in=[1,2,3]) #获取id等于1,2,3的数据 # models.UserInfo.objects.filter(id__range=[1,2]) #获取范围bettwen and(两者之间) # models.UserInfo.objects.filter(name__startswith='xxxx') #获取其它类似 # models.UserInfo.objects.filter(name__contains='xxxx') #获取包含某字符串 # models.UserInfo.objects.exclude(id=1) #排除 # 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) django Q和F查询 Q查询——对对象的复杂查询 F查询——专门取对象中某列值的操作 # 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： #Q对象可以与关键字参数查询一起使用，不过一定要把Q对象放在关键字参数查询的前面。 # 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)) 可以组合使用&,|操作符，当一个操作符是用于两个Q的对象,它产生一个新的Q对象 # 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 extra(额外的) 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)
加深理解 ：http://www.cnblogs.com/wupeiqi/articles/6216618.html
http://www.cnblogs.com/wupeiqi/articles/5237704.html
http://www.cnblogs.com/wupeiqi/articles/5246483.html
http://www.cnblogs.com/caseast/p/4806213.html
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