Django \u662f\u4e00\u4e2a\u57fa\u4e8e Python \u7684\u5168\u6808 Web \u6846\u67b6\uff0c\u9002\u5408\u6784\u5efa\u540e\u53f0\u7ba1\u7406\u7cfb\u7edf\u3001\u4e1a\u52a1 API\u3001\u5185\u5bb9\u5e73\u53f0\u3001\u7535\u5546\u7cfb\u7edf\u548c\u4f01\u4e1a\u5185\u90e8\u5de5\u5177\u3002<\/p>\n
\u5b83\u7684\u6838\u5fc3\u4ef7\u503c\u662f\uff1a\u5f00\u53d1\u8005\u4e0d\u5fc5\u4ece\u96f6\u62fc\u88c5\u8def\u7531\u3001\u6570\u636e\u5e93\u8bbf\u95ee\u3001\u7528\u6237\u8ba4\u8bc1\u3001\u540e\u53f0\u7ba1\u7406\u3001\u8868\u5355\u6821\u9a8c\u7b49\u57fa\u7840\u80fd\u529b\uff0c\u800c\u662f\u53ef\u4ee5\u628a\u7cbe\u529b\u96c6\u4e2d\u5728\u4e1a\u52a1\u89c4\u5219\u4e0a\u3002<\/p>\n
\u4e00\u4e2a Web \u670d\u52a1\u901a\u5e38\u8981\u5904\u7406\uff1a<\/p>\n
Django \u63d0\u4f9b\u4e86\u4e00\u5957\u76f8\u4e92\u534f\u4f5c\u7684\u6807\u51c6\u7ec4\u4ef6\u6765\u89e3\u51b3\u8fd9\u4e9b\u95ee\u9898\u3002<\/p>\n
\u5ba2\u6237\u7aef\n \u2193 HTTP Request\nDjango \u8def\u7531\u7cfb\u7edf\n \u2193\nView\uff08\u89c6\u56fe \/ \u4e1a\u52a1\u5165\u53e3\uff09\n \u2193\nModel \/ ORM\uff08\u6570\u636e\u5e93\u64cd\u4f5c\uff09\n \u2193\nSerializer \u6216 Template\uff08\u8f93\u51fa\u6570\u636e\uff09\n \u2193 HTTP Response\n\u5ba2\u6237\u7aef<\/code><\/pre>\n
\n2. Django \u7684\u6838\u5fc3\u8bbe\u8ba1\uff1aMVT<\/h2>\n
Django \u5e38\u88ab\u79f0\u4e3a MVT \u67b6\u6784\uff1a<\/p>\n
\n\n\n\u5c42\u7ea7<\/th>\n \u5168\u79f0<\/th>\n \u804c\u8d23<\/th>\n<\/tr>\n<\/thead>\n \n\nModel<\/td>\n \u6570\u636e\u6a21\u578b<\/td>\n \u63cf\u8ff0\u548c\u64cd\u4f5c\u6570\u636e\u5e93<\/td>\n<\/tr>\n \nView<\/td>\n \u89c6\u56fe<\/td>\n \u63a5\u6536\u8bf7\u6c42\u3001\u5904\u7406\u4e1a\u52a1\u3001\u8fd4\u56de\u54cd\u5e94<\/td>\n<\/tr>\n \nTemplate<\/td>\n \u6a21\u677f<\/td>\n \u751f\u6210 HTML \u9875\u9762<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\u5b83\u548c\u5e38\u89c1\u7684 MVC \u5f88\u50cf\uff1a<\/p>\n
MVC Django MVT\nController \u2192 View\nView \u2192 Template\nModel \u2192 Model<\/code><\/pre>\n\u5bf9\u4e8e\u524d\u540e\u7aef\u5206\u79bb\u9879\u76ee\uff0cTemplate \u5e38\u88ab\u5f31\u5316\uff0cView \u901a\u5e38\u76f4\u63a5\u8fd4\u56de JSON\u3002<\/p>\n
\n3. \u4e00\u4e2a\u8bf7\u6c42\u5728 Django \u4e2d\u5982\u4f55\u6d41\u8f6c\uff1f<\/h2>\n
\u5047\u8bbe\u5ba2\u6237\u7aef\u8bf7\u6c42\uff1a<\/p>\n
GET \/api\/users\/42\/<\/code><\/pre>\n\u5904\u7406\u8fc7\u7a0b\u901a\u5e38\u662f\uff1a<\/p>\n
1. Web Server \u63a5\u6536\u8bf7\u6c42\n2. Django \u52a0\u8f7d\u914d\u7f6e\u4e0e\u4e2d\u95f4\u4ef6\n3. URL \u8def\u7531\u5339\u914d \/api\/users\/42\/\n4. View \u63a5\u6536\u5230 request \u548c user_id=42\n5. View \u4f7f\u7528 ORM \u67e5\u8be2\u6570\u636e\u5e93\n6. \u5c06\u5bf9\u8c61\u8f6c\u6362\u4e3a JSON \u6216 HTML\n7. \u4e2d\u95f4\u4ef6\u5904\u7406\u54cd\u5e94\n8. \u8fd4\u56de HTTP \u54cd\u5e94\u7ed9\u5ba2\u6237\u7aef<\/code><\/pre>\n\u4f2a\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
# urls.py\npath("api\/users\/<int:user_id>\/", views.user_detail)<\/code><\/pre>\n# views.py\ndef user_detail(request, user_id):\n user = User.objects.get(id=user_id)\n return JsonResponse({\n "id": user.id,\n "name": user.name,\n })<\/code><\/pre>\n
\n4. \u9879\u76ee\u914d\u7f6e\uff1aSettings<\/h1>\n
Django \u9879\u76ee\u6709\u4e00\u4e2a\u914d\u7f6e\u4e2d\u5fc3\uff0c\u901a\u5e38\u53eb settings.py<\/code>\u3002\u5b83\u8d1f\u8d23\u58f0\u660e\u6574\u4e2a\u5e94\u7528\u5982\u4f55\u8fd0\u884c\u3002<\/p>\n\u5e38\u89c1\u914d\u7f6e\u5305\u62ec\uff1a<\/p>\n
DEBUG = False\n\nINSTALLED_APPS = [\n "django.contrib.auth",\n "django.contrib.contenttypes",\n "django.contrib.sessions",\n]\n\nMIDDLEWARE = [\n "django.middleware.security.SecurityMiddleware",\n "django.contrib.sessions.middleware.SessionMiddleware",\n]\n\nDATABASES = {\n "default": {\n "ENGINE": "django.db.backends.sqlite3",\n "NAME": "db.sqlite3",\n }\n}<\/code><\/pre>\n\u5e38\u89c1\u914d\u7f6e\u9879\uff1a<\/p>\n
\n\n\n\u914d\u7f6e<\/th>\n \u4f5c\u7528<\/th>\n<\/tr>\n<\/thead>\n \n\nDEBUG<\/code><\/td>\n\u662f\u5426\u5f00\u542f\u5f00\u53d1\u8c03\u8bd5\u6a21\u5f0f<\/td>\n<\/tr>\n \nINSTALLED_APPS<\/code><\/td>\n\u5df2\u5b89\u88c5\u7684 Django App<\/td>\n<\/tr>\n \nMIDDLEWARE<\/code><\/td>\n\u8bf7\u6c42\/\u54cd\u5e94\u5904\u7406\u94fe<\/td>\n<\/tr>\n \nDATABASES<\/code><\/td>\n\u6570\u636e\u5e93\u8fde\u63a5\u914d\u7f6e<\/td>\n<\/tr>\n \nCACHES<\/code><\/td>\n\u7f13\u5b58\u914d\u7f6e<\/td>\n<\/tr>\n \nLOGGING<\/code><\/td>\n\u65e5\u5fd7\u914d\u7f6e<\/td>\n<\/tr>\n \nALLOWED_HOSTS<\/code><\/td>\n\u5141\u8bb8\u8bbf\u95ee\u7684\u4e3b\u673a\u540d<\/td>\n<\/tr>\n \nROOT_URLCONF<\/code><\/td>\n\u6839\u8def\u7531\u6a21\u5757<\/td>\n<\/tr>\n \nTEMPLATES<\/code><\/td>\n\u6a21\u677f\u5f15\u64ce\u914d\u7f6e<\/td>\n<\/tr>\n \nSTATIC_URL<\/code><\/td>\n\u9759\u6001\u6587\u4ef6\u8bbf\u95ee\u524d\u7f00<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\u8bfb\u53d6\u914d\u7f6e\uff1a<\/p>\n
from django.conf import settings\n\nif settings.DEBUG:\n print("\u5f53\u524d\u4e3a\u5f00\u53d1\u8c03\u8bd5\u6a21\u5f0f")<\/code><\/pre>\nDEBUG<\/code> \u7684\u610f\u4e49<\/h2>\nDEBUG = True<\/code><\/pre>\n\u901a\u5e38\u7528\u4e8e\u5f00\u53d1\u73af\u5883\uff0c\u7279\u70b9\uff1a<\/p>\n
\n- \u9875\u9762\u4f1a\u663e\u793a\u8be6\u7ec6\u62a5\u9519\u5806\u6808\uff1b<\/li>\n
- \u9759\u6001\u6587\u4ef6\u5904\u7406\u66f4\u65b9\u4fbf\uff1b<\/li>\n
- \u6709\u5229\u4e8e\u6392\u67e5\u95ee\u9898\uff1b<\/li>\n
- \u4e0d\u9002\u5408\u751f\u4ea7\u73af\u5883\u3002<\/li>\n<\/ul>\n
DEBUG = False<\/code><\/pre>\n\u901a\u5e38\u7528\u4e8e\u751f\u4ea7\u73af\u5883\uff0c\u7279\u70b9\uff1a<\/p>\n
\n- \u907f\u514d\u5411\u5916\u66b4\u9732\u4ee3\u7801\u8def\u5f84\u3001\u914d\u7f6e\u548c\u62a5\u9519\u8be6\u60c5\uff1b<\/li>\n
- \u9700\u8981\u6b63\u786e\u914d\u7f6e
ALLOWED_HOSTS<\/code>\uff1b<\/li>\n- \u5e94\u901a\u8fc7\u65e5\u5fd7\u7cfb\u7edf\u6392\u67e5\u5f02\u5e38\u3002<\/li>\n<\/ul>\n
\u751f\u4ea7\u73af\u5883\u4e0d\u8981\u5f00\u542f DEBUG=True<\/code>\u3002<\/p>\n
\n5. URL \u8def\u7531\uff1adjango.urls<\/code><\/h1>\nURL \u8def\u7531\u51b3\u5b9a\u201c\u4ec0\u4e48\u8def\u5f84\u4ea4\u7ed9\u4ec0\u4e48\u4ee3\u7801\u5904\u7406\u201d\u3002<\/p>\n
from django.urls import path\nfrom . import views\n\nurlpatterns = [\n path("hello\/", views.hello),\n path("users\/<int:user_id>\/", views.user_detail),\n]<\/code><\/pre>\n\u8bf7\u6c42\u548c\u8def\u7531\u7684\u5173\u7cfb\uff1a<\/p>\n
GET \/hello\/\n \u2193\nviews.hello\n\nGET \/users\/100\/\n \u2193\nviews.user_detail(request, user_id=100)<\/code><\/pre>\n\u8def\u7531\u53c2\u6570<\/h2>\npath("articles\/<int:article_id>\/", views.article_detail)<\/code><\/pre>\n\u5bf9\u5e94\u89c6\u56fe\uff1a<\/p>\n
def article_detail(request, article_id):\n return JsonResponse({"article_id": article_id})<\/code><\/pre>\nDjango \u5e38\u7528\u8def\u5f84\u8f6c\u6362\u5668\uff1a<\/p>\n
\n\n\n\u5199\u6cd5<\/th>\n \u5339\u914d\u5185\u5bb9<\/th>\n<\/tr>\n<\/thead>\n \n\n<int:id><\/code><\/td>\n\u6574\u6570<\/td>\n<\/tr>\n \n<str:name><\/code><\/td>\n\u666e\u901a\u5b57\u7b26\u4e32<\/td>\n<\/tr>\n \n<slug:slug><\/code><\/td>\nURL \u53cb\u597d\u5b57\u7b26\u4e32<\/td>\n<\/tr>\n \n<uuid:id><\/code><\/td>\nUUID<\/td>\n<\/tr>\n \n<path:value><\/code><\/td>\n\u542b \/<\/code> \u7684\u8def\u5f84<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\u8def\u7531\u62c6\u5206<\/h2>\n
\u5927\u578b\u9879\u76ee\u901a\u5e38\u6309\u4e1a\u52a1\u6a21\u5757\u62c6\u5206\u8def\u7531\u3002<\/p>\n
# project\/urls.py\nfrom django.urls import include, path\n\nurlpatterns = [\n path("api\/users\/", include("users.urls")),\n path("api\/orders\/", include("orders.urls")),\n]<\/code><\/pre>\n# users\/urls.py\nurlpatterns = [\n path("", views.user_list),\n path("<int:user_id>\/", views.user_detail),\n]<\/code><\/pre>\n
\n6. View\uff1a\u8bf7\u6c42\u5904\u7406\u5165\u53e3<\/h1>\n
View \u7684\u804c\u8d23\u662f\uff1a<\/p>\n
\n- \u63a5\u6536\u8bf7\u6c42\uff1b<\/li>\n
- \u8bfb\u53d6\u53c2\u6570\uff1b<\/li>\n
- \u8c03\u7528\u4e1a\u52a1\u903b\u8f91\uff1b<\/li>\n
- \u67e5\u8be2\u6216\u66f4\u65b0\u6570\u636e\uff1b<\/li>\n
- \u8fd4\u56de HTTP \u54cd\u5e94\u3002<\/li>\n<\/ol>\n
\u51fd\u6570\u89c6\u56fe<\/h2>\n
\u6700\u7b80\u5355\u7684\u5f62\u5f0f\uff1a<\/p>\n
from django.http import JsonResponse\n\ndef health_check(request):\n return JsonResponse({\n "status": "ok",\n })<\/code><\/pre>\n\u8bfb\u53d6\u67e5\u8be2\u53c2\u6570\uff1a<\/p>\n
def user_list(request):\n page = request.GET.get("page", 1)\n return JsonResponse({"page": page})<\/code><\/pre>\n\u5bf9\u4e8e\uff1a<\/p>\n
GET \/users\/?page=2<\/code><\/pre>\npage<\/code> \u7684\u503c\u662f "2"<\/code>\uff0c\u9700\u8981\u65f6\u81ea\u884c\u8f6c\u6362\u4e3a\u6574\u6570\u3002<\/p>\n\u7c7b\u89c6\u56fe<\/h2>\n
\u5f53\u4e00\u4e2a\u8d44\u6e90\u9700\u8981\u5904\u7406\u591a\u79cd HTTP \u65b9\u6cd5\u65f6\uff0c\u7c7b\u89c6\u56fe\u66f4\u6e05\u6670\u3002<\/p>\n
from django.http import JsonResponse\nfrom django.views import View\n\nclass UserView(View):\n def get(self, request):\n return JsonResponse({"method": "GET"})\n\n def post(self, request):\n return JsonResponse({"method": "POST"})<\/code><\/pre>\n\u8def\u7531\uff1a<\/p>\n
path("users\/", UserView.as_view())<\/code><\/pre>\n\u8bf7\u6c42\u6620\u5c04\uff1a<\/p>\n
GET \/users\/ \u2192 UserView.get()\nPOST \/users\/ \u2192 UserView.post()<\/code><\/pre>\n
\n7. HTTP \u8bf7\u6c42\u4e0e\u54cd\u5e94<\/h1>\n
Django \u7528 HttpRequest<\/code> \u8868\u793a\u8bf7\u6c42\uff0c\u7528 HttpResponse<\/code> \u8868\u793a\u54cd\u5e94\u3002<\/p>\n\u8bf7\u6c42\u5bf9\u8c61<\/h2>\ndef example(request):\n method = request.method\n query_params = request.GET\n form_data = request.POST\n headers = request.headers\n raw_body = request.body\n files = request.FILES\n current_user = request.user<\/code><\/pre>\n\u5e38\u89c1\u573a\u666f\uff1a<\/p>\n
def search(request):\n keyword = request.GET.get("keyword", "")\n return JsonResponse({"keyword": keyword})<\/code><\/pre>\n\u8bf7\u6c42\uff1a<\/p>\n
GET \/search\/?keyword=django<\/code><\/pre>\n\u54cd\u5e94\u5bf9\u8c61<\/h2>\nfrom django.http import HttpResponse, JsonResponse\n\ndef text_response(request):\n return HttpResponse("Hello")\n\ndef json_response(request):\n return JsonResponse({\n "code": 0,\n "message": "success",\n "data": {},\n })<\/code><\/pre>\n\u6307\u5b9a\u72b6\u6001\u7801\uff1a<\/p>\n
return JsonResponse(\n {"message": "not found"},\n status=404,\n)<\/code><\/pre>\n\u5e38\u89c1\u72b6\u6001\u7801\uff1a<\/p>\n
\n\n\n\u72b6\u6001\u7801<\/th>\n \u542b\u4e49<\/th>\n<\/tr>\n<\/thead>\n \n\n200<\/code><\/td>\n\u8bf7\u6c42\u6210\u529f<\/td>\n<\/tr>\n \n201<\/code><\/td>\n\u521b\u5efa\u6210\u529f<\/td>\n<\/tr>\n \n204<\/code><\/td>\n\u6210\u529f\u4f46\u65e0\u8fd4\u56de\u5185\u5bb9<\/td>\n<\/tr>\n \n400<\/code><\/td>\n\u8bf7\u6c42\u53c2\u6570\u9519\u8bef<\/td>\n<\/tr>\n \n401<\/code><\/td>\n\u672a\u8ba4\u8bc1<\/td>\n<\/tr>\n \n403<\/code><\/td>\n\u65e0\u6743\u9650<\/td>\n<\/tr>\n \n404<\/code><\/td>\n\u8d44\u6e90\u4e0d\u5b58\u5728<\/td>\n<\/tr>\n \n500<\/code><\/td>\n\u670d\u52a1\u7aef\u5f02\u5e38<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n8. Model \u4e0e ORM\uff1a\u7528 Python \u64cd\u4f5c\u6570\u636e\u5e93<\/h1>\n
Django ORM \u662f\u5176\u6700\u91cd\u8981\u7684\u80fd\u529b\u4e4b\u4e00\u3002\u5b83\u8ba9\u5f00\u53d1\u8005\u53ef\u4ee5\u7528 Python \u7c7b\u63cf\u8ff0\u6570\u636e\u5e93\u8868\uff0c\u5e76\u7528 Python \u65b9\u6cd5\u5b8c\u6210\u589e\u5220\u6539\u67e5\u3002<\/p>\n
from django.db import models\n\nclass User(models.Model):\n name = models.CharField(max_length=100)\n email = models.EmailField(unique=True)\n age = models.IntegerField(default=0)\n is_active = models.BooleanField(default=True)\n created_at = models.DateTimeField(auto_now_add=True)<\/code><\/pre>\n\u8fd9\u4e2a\u7c7b\u5927\u81f4\u5bf9\u5e94\u4e00\u5f20\u7528\u6237\u8868\uff1a<\/p>\n
user\n\u251c\u2500\u2500 id\n\u251c\u2500\u2500 name\n\u251c\u2500\u2500 email\n\u251c\u2500\u2500 age\n\u251c\u2500\u2500 is_active\n\u2514\u2500\u2500 created_at<\/code><\/pre>\n\u5e38\u89c1\u5b57\u6bb5<\/h2>\n
\n\n\n\u5b57\u6bb5<\/th>\n \u7528\u9014<\/th>\n<\/tr>\n<\/thead>\n \n\nCharField<\/code><\/td>\n\u77ed\u6587\u672c<\/td>\n<\/tr>\n \nTextField<\/code><\/td>\n\u957f\u6587\u672c<\/td>\n<\/tr>\n \nIntegerField<\/code><\/td>\n\u6574\u6570<\/td>\n<\/tr>\n \nBooleanField<\/code><\/td>\n\u5e03\u5c14\u503c<\/td>\n<\/tr>\n \nDateField<\/code><\/td>\n\u65e5\u671f<\/td>\n<\/tr>\n \nDateTimeField<\/code><\/td>\n\u65e5\u671f\u65f6\u95f4<\/td>\n<\/tr>\n \nDecimalField<\/code><\/td>\n\u7cbe\u786e\u5c0f\u6570\uff0c\u5982\u91d1\u989d<\/td>\n<\/tr>\n \nJSONField<\/code><\/td>\nJSON \u6570\u636e<\/td>\n<\/tr>\n \nEmailField<\/code><\/td>\n\u90ae\u7bb1<\/td>\n<\/tr>\n \nURLField<\/code><\/td>\nURL<\/td>\n<\/tr>\n \nFileField<\/code><\/td>\n\u6587\u4ef6<\/td>\n<\/tr>\n \nImageField<\/code><\/td>\n\u56fe\u7247<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\u521b\u5efa\u6570\u636e<\/h2>\nUser.objects.create(\n name="Alice",\n email="alice@example.com",\n age=18,\n)<\/code><\/pre>\n\u67e5\u8be2\u6570\u636e<\/h2>\nUser.objects.all()\n\nUser.objects.get(id=1)\n\nUser.objects.filter(is_active=True)\n\nUser.objects.filter(age__gte=18)\n\nUser.objects.order_by("-created_at")\n\nUser.objects.first()\n\nUser.objects.count()\n\nUser.objects.exists()<\/code><\/pre>\nget()<\/code> \u627e\u4e0d\u5230\u6216\u7ed3\u679c\u8d85\u8fc7\u4e00\u6761\u4f1a\u629b\u5f02\u5e38\uff1bfilter()<\/code> \u59cb\u7ec8\u8fd4\u56de QuerySet\uff0c\u5373\u4f7f\u6ca1\u6709\u7ed3\u679c\u4e5f\u4e0d\u4f1a\u629b\u5f02\u5e38\u3002<\/p>\n\u66f4\u65b0\u6570\u636e<\/h2>\nuser = User.objects.get(id=1)\nuser.age = 20\nuser.save()<\/code><\/pre>\n\u6279\u91cf\u66f4\u65b0\uff1a<\/p>\n
User.objects.filter(is_active=False).update(is_active=True)<\/code><\/pre>\n\u5220\u9664\u6570\u636e<\/h2>\nUser.objects.filter(id=1).delete()<\/code><\/pre>\n
\n9. \u8868\u5173\u7cfb<\/h1>\n
\u5b9e\u9645\u4e1a\u52a1\u4e2d\uff0c\u8868\u4e4b\u95f4\u5f80\u5f80\u6709\u5173\u8054\u3002<\/p>\n
\u4e00\u5bf9\u591a\uff1aForeignKey<\/code><\/h2>\n\u4e00\u4e2a\u7528\u6237\u53ef\u4ee5\u62e5\u6709\u591a\u4e2a\u8ba2\u5355\u3002<\/p>\n
class Order(models.Model):\n user = models.ForeignKey(\n User,\n on_delete=models.CASCADE,\n related_name="orders",\n )\n amount = models.DecimalField(max_digits=10, decimal_places=2)<\/code><\/pre>\n\u67e5\u8be2\uff1a<\/p>\n
order.user\nuser.orders.all()<\/code><\/pre>\n\u4e00\u5bf9\u4e00\uff1aOneToOneField<\/code><\/h2>\n\u4e00\u4e2a\u7528\u6237\u5bf9\u5e94\u4e00\u4efd\u6269\u5c55\u8d44\u6599\u3002<\/p>\n
class UserProfile(models.Model):\n user = models.OneToOneField(\n User,\n on_delete=models.CASCADE,\n )\n avatar = models.URLField()<\/code><\/pre>\n\u591a\u5bf9\u591a\uff1aManyToManyField<\/code><\/h2>\n\u4e00\u4e2a\u7528\u6237\u53ef\u62e5\u6709\u591a\u4e2a\u89d2\u8272\uff0c\u4e00\u4e2a\u89d2\u8272\u4e5f\u53ef\u5206\u914d\u7ed9\u591a\u4e2a\u7528\u6237\u3002<\/p>\n
class Role(models.Model):\n name = models.CharField(max_length=50)\n\nclass User(models.Model):\n roles = models.ManyToManyField(Role)<\/code><\/pre>\n
\n10. \u67e5\u8be2\u4f18\u5316\uff1a\u907f\u514d N+1 \u95ee\u9898<\/h1>\n
\u4e0b\u9762\u7684\u4ee3\u7801\u53ef\u80fd\u89e6\u53d1 N+1 \u6b21\u6570\u636e\u5e93\u67e5\u8be2\uff1a<\/p>\n
orders = Order.objects.all()\n\nfor order in orders:\n print(order.user.name)<\/code><\/pre>\n\u539f\u56e0\u662f\u6bcf\u8bbf\u95ee\u4e00\u6b21 order.user<\/code>\uff0c\u90fd\u53ef\u80fd\u989d\u5916\u67e5\u8be2\u4e00\u6b21\u7528\u6237\u8868\u3002<\/p>\n\u5bf9\u4e8e\u5916\u952e\u6216\u4e00\u5bf9\u4e00\u5173\u7cfb\uff0c\u4f7f\u7528 select_related()<\/code>\uff1a<\/p>\norders = Order.objects.select_related("user")<\/code><\/pre>\n\u5bf9\u4e8e\u591a\u5bf9\u591a\u6216\u53cd\u5411\u5173\u7cfb\uff0c\u4f7f\u7528 prefetch_related()<\/code>\uff1a<\/p>\nusers = User.objects.prefetch_related("roles")<\/code><\/pre>\n\u8fd9\u662f Django \u9879\u76ee\u6027\u80fd\u4f18\u5316\u4e2d\u975e\u5e38\u91cd\u8981\u7684\u4e00\u70b9\u3002<\/p>\n
\n11. \u6570\u636e\u5e93\u8fc1\u79fb\uff1a\u8ba9\u6a21\u578b\u53d8\u6210\u8868<\/h1>\n
\u4fee\u6539 Model \u540e\uff0c\u9700\u8981\u901a\u8fc7\u8fc1\u79fb\u628a\u53d8\u66f4\u540c\u6b65\u5230\u6570\u636e\u5e93\u3002<\/p>\n
python manage.py makemigrations\npython manage.py migrate<\/code><\/pre>\n\u6d41\u7a0b\uff1a<\/p>\n
\u4fee\u6539 models.py\n \u2193\nmakemigrations\uff1a\u751f\u6210\u8fc1\u79fb\u6587\u4ef6\n \u2193\nmigrate\uff1a\u6267\u884c\u8fc1\u79fb\uff0c\u4fee\u6539\u6570\u636e\u5e93\u7ed3\u6784<\/code><\/pre>\n