{"id":5779,"date":"2022-04-03T09:54:12","date_gmt":"2022-04-03T01:54:12","guid":{"rendered":"https:\/\/egonlin.com\/?p=5779"},"modified":"2022-04-26T14:30:44","modified_gmt":"2022-04-26T06:30:44","slug":"05-04-django%e4%b9%8b%e6%a8%a1%e5%9e%8b%e5%b1%82%e7%ac%ac%e5%9b%9b%e7%af%87%ef%bc%9a%e8%bf%9b%e9%98%b6%e6%93%8d%e4%bd%9c","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=5779","title":{"rendered":"05-04 \u6a21\u578b\u5c42\u7b2c\u56db\u7bc7\uff1a\u8fdb\u9636\u64cd\u4f5c"},"content":{"rendered":"<h1>Django-model\u8fdb\u9636<\/h1>\n<h2>\u4e00 QuerySet\u5bf9\u8c61<\/h2>\n<h3>1.1\u53ef\u5207\u7247<\/h3>\n<p>\u4f7f\u7528Python \u7684\u5207\u7247\u8bed\u6cd5\u6765\u9650\u5236\u67e5\u8be2\u96c6\u8bb0\u5f55\u7684\u6570\u76ee \u3002\u5b83\u7b49\u540c\u4e8eSQL \u7684LIMIT \u548cOFFSET \u5b50\u53e5\u3002<\/p>\n<pre><code class=\"language-yaml\">Entry.objects.all()[:5]      # (LIMIT 5)\nEntry.objects.all()[5:10]    # (OFFSET 5 LIMIT 5)<\/code><\/pre>\n<p>\u4e0d\u652f\u6301\u8d1f\u7684\u7d22\u5f15\uff08\u4f8b\u5982Entry.objects.all()[-1]\uff09\u3002\u901a\u5e38\uff0c\u67e5\u8be2\u96c6 \u7684\u5207\u7247\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684\u67e5\u8be2\u96c6 \u2014\u2014 \u5b83\u4e0d\u4f1a\u6267\u884c\u67e5\u8be2\u3002<\/p>\n<h3>1.2\u53ef\u8fed\u4ee3<\/h3>\n<pre><code class=\"language-yaml\">articleList=models.Article.objects.all()\n\nfor article in articleList:\n    print(article.title)<\/code><\/pre>\n<h3>1.3\u60f0\u6027\u67e5\u8be2<\/h3>\n<p>\u67e5\u8be2\u96c6 \u662f\u60f0\u6027\u6267\u884c\u7684 \u2014\u2014 \u521b\u5efa\u67e5\u8be2\u96c6\u4e0d\u4f1a\u5e26\u6765\u4efb\u4f55\u6570\u636e\u5e93\u7684\u8bbf\u95ee\u3002\u4f60\u53ef\u4ee5\u5c06\u8fc7\u6ee4\u5668\u4fdd\u6301\u4e00\u6574\u5929\uff0c\u76f4\u5230\u67e5\u8be2\u96c6 \u9700\u8981\u6c42\u503c\u65f6\uff0cDjango \u624d\u4f1a\u771f\u6b63\u8fd0\u884c\u8fd9\u4e2a\u67e5\u8be2\u3002<br \/>\n\u590d\u5236\u4ee3\u7801<\/p>\n<pre><code class=\"language-yaml\">queryResult=models.Article.objects.all() # not hits database\n\nprint(queryResult) # hits database\n\nfor article in queryResult:\n    print(article.title)    # hits database<\/code><\/pre>\n<p>\u4e00\u822c\u6765\u8bf4\uff0c\u53ea\u6709\u5728\u201c\u8bf7\u6c42\u201d\u67e5\u8be2\u96c6 \u7684\u7ed3\u679c\u65f6\u624d\u4f1a\u5230\u6570\u636e\u5e93\u4e2d\u53bb\u83b7\u53d6\u5b83\u4eec\u3002\u5f53\u4f60\u786e\u5b9e\u9700\u8981\u7ed3\u679c\u65f6\uff0c\u67e5\u8be2\u96c6 \u901a\u8fc7\u8bbf\u95ee\u6570\u636e\u5e93\u6765\u6c42\u503c<\/p>\n<h3>1.4\u7f13\u5b58\u673a\u5236<\/h3>\n<p>\u6bcf\u4e2a\u67e5\u8be2\u96c6\u90fd\u5305\u542b\u4e00\u4e2a\u7f13\u5b58\u6765\u6700\u5c0f\u5316\u5bf9\u6570\u636e\u5e93\u7684\u8bbf\u95ee\u3002\u7406\u89e3\u5b83\u662f\u5982\u4f55\u5de5\u4f5c\u7684\u5c06\u8ba9\u4f60\u7f16\u5199\u6700\u9ad8\u6548\u7684\u4ee3\u7801\u3002<\/p>\n<p>\u5728\u4e00\u4e2a\u65b0\u521b\u5efa\u7684\u67e5\u8be2\u96c6\u4e2d\uff0c\u7f13\u5b58\u4e3a\u7a7a\u3002\u9996\u6b21\u5bf9\u67e5\u8be2\u96c6\u8fdb\u884c\u6c42\u503c \u2014\u2014 \u540c\u65f6\u53d1\u751f\u6570\u636e\u5e93\u67e5\u8be2 \u2014\u2014Django \u5c06\u4fdd\u5b58\u67e5\u8be2\u7684\u7ed3\u679c\u5230\u67e5\u8be2\u96c6\u7684\u7f13\u5b58\u4e2d\u5e76\u8fd4\u56de\u660e\u786e\u8bf7\u6c42\u7684\u7ed3\u679c\uff08\u4f8b\u5982\uff0c\u5982\u679c\u6b63\u5728\u8fed\u4ee3\u67e5\u8be2\u96c6\uff0c\u5219\u8fd4\u56de\u4e0b\u4e00\u4e2a\u7ed3\u679c\uff09\u3002\u63a5\u4e0b\u6765\u5bf9\u8be5\u67e5\u8be2\u96c6 \u7684\u6c42\u503c\u5c06\u91cd\u7528\u7f13\u5b58\u7684\u7ed3\u679c\u3002<\/p>\n<p>\u8bf7\u7262\u8bb0\u8fd9\u4e2a\u7f13\u5b58\u884c\u4e3a\uff0c\u56e0\u4e3a\u5bf9\u67e5\u8be2\u96c6\u4f7f\u7528\u4e0d\u5f53\u7684\u8bdd\uff0c\u5b83\u4f1a\u5751\u4f60\u7684\u3002\u4f8b\u5982\uff0c\u4e0b\u9762\u7684\u8bed\u53e5\u521b\u5efa\u4e24\u4e2a\u67e5\u8be2\u96c6\uff0c\u5bf9\u5b83\u4eec\u6c42\u503c\uff0c\u7136\u540e\u6254\u6389\u5b83\u4eec\uff1a<\/p>\n<pre><code class=\"language-yaml\">print([a.title for a in models.Article.objects.all()])\nprint([a.create_time for a in models.Article.objects.all()])<\/code><\/pre>\n<p>\u8fd9\u610f\u5473\u7740\u76f8\u540c\u7684\u6570\u636e\u5e93\u67e5\u8be2\u5c06\u6267\u884c\u4e24\u6b21\uff0c\u663e\u7136\u500d\u589e\u4e86\u4f60\u7684\u6570\u636e\u5e93\u8d1f\u8f7d\u3002\u540c\u65f6\uff0c\u8fd8\u6709\u53ef\u80fd\u4e24\u4e2a\u7ed3\u679c\u5217\u8868\u5e76\u4e0d\u5305\u542b\u76f8\u540c\u7684\u6570\u636e\u5e93\u8bb0\u5f55\uff0c\u56e0\u4e3a\u5728\u4e24\u6b21\u8bf7\u6c42\u671f\u95f4\u6709\u53ef\u80fd\u6709Article\u88ab\u6dfb\u52a0\u8fdb\u6765\u6216\u5220\u9664\u6389\u3002\u4e3a\u4e86\u907f\u514d\u8fd9\u4e2a\u95ee\u9898\uff0c\u53ea\u9700\u4fdd\u5b58\u67e5\u8be2\u96c6\u5e76\u91cd\u65b0\u4f7f\u7528\u5b83\uff1a<\/p>\n<pre><code class=\"language-yaml\">queryResult=models.Article.objects.all()\nprint([a.title for a in queryResult])\nprint([a.create_time for a in queryResult])<\/code><\/pre>\n<h4>\u4f55\u65f6\u67e5\u8be2\u96c6\u4e0d\u4f1a\u88ab\u7f13\u5b58?<\/h4>\n<p>\u67e5\u8be2\u96c6\u4e0d\u4f1a\u6c38\u8fdc\u7f13\u5b58\u5b83\u4eec\u7684\u7ed3\u679c\u3002\u5f53\u53ea\u5bf9\u67e5\u8be2\u96c6\u7684\u90e8\u5206\u8fdb\u884c\u6c42\u503c\u65f6\u4f1a\u68c0\u67e5\u7f13\u5b58\uff0c \u5982\u679c\u8fd9\u4e2a\u90e8\u5206\u4e0d\u5728\u7f13\u5b58\u4e2d\uff0c\u90a3\u4e48\u63a5\u4e0b\u6765\u67e5\u8be2\u8fd4\u56de\u7684\u8bb0\u5f55\u90fd\u5c06\u4e0d\u4f1a\u88ab\u7f13\u5b58\u3002\u6240\u4ee5\uff0c\u8fd9\u610f\u5473\u7740\u4f7f\u7528\u5207\u7247\u6216\u7d22\u5f15\u6765\u9650\u5236\u67e5\u8be2\u96c6\u5c06\u4e0d\u4f1a\u586b\u5145\u7f13\u5b58\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u91cd\u590d\u83b7\u53d6\u67e5\u8be2\u96c6\u5bf9\u8c61\u4e2d\u4e00\u4e2a\u7279\u5b9a\u7684\u7d22\u5f15\u5c06\u6bcf\u6b21\u90fd\u67e5\u8be2\u6570\u636e\u5e93\uff1a<\/p>\n<pre><code class=\"language-yaml\">queryset = Entry.objects.all()\nprint queryset[5] # Queries the database\nprint queryset[5] # Queries the database again<\/code><\/pre>\n<p>\u7136\u800c\uff0c\u5982\u679c\u5df2\u7ecf\u5bf9\u5168\u90e8\u67e5\u8be2\u96c6\u6c42\u503c\u8fc7\uff0c\u5219\u5c06\u68c0\u67e5\u7f13\u5b58\uff1a<\/p>\n<pre><code class=\"language-yaml\">queryset = Entry.objects.all()\n[entry for entry in queryset] # Queries the database\nprint queryset[5] # Uses cache\nprint queryset[5] # Uses cache\n<\/code><\/pre>\n<p>\u4e0b\u9762\u662f\u4e00\u4e9b\u5176\u5b83\u4f8b\u5b50\uff0c\u5b83\u4eec\u4f1a\u4f7f\u5f97\u5168\u90e8\u7684\u67e5\u8be2\u96c6\u88ab\u6c42\u503c\u5e76\u586b\u5145\u5230\u7f13\u5b58\u4e2d\uff1a<\/p>\n<pre><code class=\"language-yaml\">[entry for entry in queryset]\nbool(queryset)\nentry in queryset\nlist(queryset)<\/code><\/pre>\n<p>\u6ce8\uff1a\u7b80\u5355\u5730\u6253\u5370\u67e5\u8be2\u96c6\u4e0d\u4f1a\u586b\u5145\u7f13\u5b58\u3002<\/p>\n<pre><code class=\"language-yaml\">queryResult=models.Article.objects.all()\nprint(queryResult) #  hits database\nprint(queryResult) #  hits database<\/code><\/pre>\n<h3>1.5 exists()\u4e0eiterator()\u65b9\u6cd5<\/h3>\n<h5>exists\uff1a<\/h5>\n<p>\u7b80\u5355\u7684\u4f7f\u7528if\u8bed\u53e5\u8fdb\u884c\u5224\u65ad\u4e5f\u4f1a\u5b8c\u5168\u6267\u884c\u6574\u4e2aqueryset\u5e76\u4e14\u628a\u6570\u636e\u653e\u5165cache\uff0c\u867d\u7136\u4f60\u5e76\u4e0d\u9700\u8981\u8fd9\u4e9b \u6570\u636e\uff01\u4e3a\u4e86\u907f\u514d\u8fd9\u4e2a\uff0c\u53ef\u4ee5\u7528exists()\u65b9\u6cd5\u6765\u68c0\u67e5\u662f\u5426\u6709\u6570\u636e\uff1a<\/p>\n<pre><code class=\"language-yaml\">if queryResult.exists():\n    #SELECT (1) AS &quot;a&quot; FROM &quot;blog_article&quot; LIMIT 1; args=()\n        print(&quot;exists...&quot;)<\/code><\/pre>\n<h5>iterator:<\/h5>\n<p>\u5f53queryset\u975e\u5e38\u5de8\u5927\u65f6\uff0ccache\u4f1a\u6210\u4e3a\u95ee\u9898\u3002<\/p>\n<p>\u5904\u7406\u6210\u5343\u4e0a\u4e07\u7684\u8bb0\u5f55\u65f6\uff0c\u5c06\u5b83\u4eec\u4e00\u6b21\u88c5\u5165\u5185\u5b58\u662f\u5f88\u6d6a\u8d39\u7684\u3002\u66f4\u7cdf\u7cd5\u7684\u662f\uff0c\u5de8\u5927\u7684queryset\u53ef\u80fd\u4f1a\u9501\u4f4f\u7cfb\u7edf \u8fdb\u7a0b\uff0c\u8ba9\u4f60\u7684\u7a0b\u5e8f\u6fd2\u4e34\u5d29\u6e83\u3002\u8981\u907f\u514d\u5728\u904d\u5386\u6570\u636e\u7684\u540c\u65f6\u4ea7\u751fqueryset cache\uff0c\u53ef\u4ee5\u4f7f\u7528iterator()\u65b9\u6cd5 \u6765\u83b7\u53d6\u6570\u636e\uff0c\u5904\u7406\u5b8c\u6570\u636e\u5c31\u5c06\u5176\u4e22\u5f03\u3002<\/p>\n<pre><code class=\"language-yaml\">objs = Book.objects.all().iterator()\n# iterator()\u53ef\u4ee5\u4e00\u6b21\u53ea\u4ece\u6570\u636e\u5e93\u83b7\u53d6\u5c11\u91cf\u6570\u636e\uff0c\u8fd9\u6837\u53ef\u4ee5\u8282\u7701\u5185\u5b58\nfor obj in objs:\n    print(obj.title)\n#BUT,\u518d\u6b21\u904d\u5386\u6ca1\u6709\u6253\u5370,\u56e0\u4e3a\u8fed\u4ee3\u5668\u5df2\u7ecf\u5728\u4e0a\u4e00\u6b21\u904d\u5386(next)\u5230\u6700\u540e\u4e00\u6b21\u4e86,\u6ca1\u5f97\u904d\u5386\u4e86\nfor obj in objs:\n    print(obj.title)<\/code><\/pre>\n<p>\u5f53\u7136\uff0c\u4f7f\u7528iterator()\u65b9\u6cd5\u6765\u9632\u6b62\u751f\u6210cache\uff0c\u610f\u5473\u7740\u904d\u5386\u540c\u4e00\u4e2aqueryset\u65f6\u4f1a\u91cd\u590d\u6267\u884c\u67e5\u8be2\u3002\u6240\u4ee5\u4f7f #\u7528iterator()\u7684\u65f6\u5019\u8981\u5f53\u5fc3\uff0c\u786e\u4fdd\u4f60\u7684\u4ee3\u7801\u5728\u64cd\u4f5c\u4e00\u4e2a\u5927\u7684queryset\u65f6\u6ca1\u6709\u91cd\u590d\u6267\u884c\u67e5\u8be2\u3002<\/p>\n<h6>\u603b\u7ed3:<\/h6>\n<p>queryset\u7684cache\u662f\u7528\u4e8e\u51cf\u5c11\u7a0b\u5e8f\u5bf9\u6570\u636e\u5e93\u7684\u67e5\u8be2\uff0c\u5728\u901a\u5e38\u7684\u4f7f\u7528\u4e0b\u4f1a\u4fdd\u8bc1\u53ea\u6709\u5728\u9700\u8981\u7684\u65f6\u5019\u624d\u4f1a\u67e5\u8be2\u6570\u636e\u5e93\u3002 \u4f7f\u7528exists()\u548citerator()\u65b9\u6cd5\u53ef\u4ee5\u4f18\u5316\u7a0b\u5e8f\u5bf9\u5185\u5b58\u7684\u4f7f\u7528\u3002\u4e0d\u8fc7\uff0c\u7531\u4e8e\u5b83\u4eec\u5e76\u4e0d\u4f1a\u751f\u6210queryset cache\uff0c\u53ef\u80fd \u4f1a\u9020\u6210\u989d\u5916\u7684\u6570\u636e\u5e93\u67e5\u8be2\u3002<\/p>\n<h2>\u4e8c \u4e2d\u4ecb\u6a21\u578b<\/h2>\n<p>\u5904\u7406\u7c7b\u4f3c\u642d\u914d pizza \u548c topping \u8fd9\u6837\u7b80\u5355\u7684\u591a\u5bf9\u591a\u5173\u7cfb\u65f6\uff0c\u4f7f\u7528\u6807\u51c6\u7684ManyToManyField  \u5c31\u53ef\u4ee5\u4e86\u3002\u4f46\u662f\uff0c\u6709\u65f6\u4f60\u53ef\u80fd\u9700\u8981\u5173\u8054\u6570\u636e\u5230\u4e24\u4e2a\u6a21\u578b\u4e4b\u95f4\u7684\u5173\u7cfb\u4e0a\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u6709\u8fd9\u6837\u4e00\u4e2a\u5e94\u7528\uff0c\u5b83\u8bb0\u5f55\u97f3\u4e50\u5bb6\u6240\u5c5e\u7684\u97f3\u4e50\u5c0f\u7ec4\u3002\u6211\u4eec\u53ef\u4ee5\u7528\u4e00\u4e2aManyToManyField \u8868\u793a\u5c0f\u7ec4\u548c\u6210\u5458\u4e4b\u95f4\u7684\u591a\u5bf9\u591a\u5173\u7cfb\u3002\u4f46\u662f\uff0c\u6709\u65f6\u4f60\u53ef\u80fd\u60f3\u77e5\u9053\u66f4\u591a\u6210\u5458\u5173\u7cfb\u7684\u7ec6\u8282\uff0c\u6bd4\u5982\u6210\u5458\u662f\u4f55\u65f6\u52a0\u5165\u5c0f\u7ec4\u7684\u3002<\/p>\n<p>\u5bf9\u4e8e\u8fd9\u4e9b\u60c5\u51b5\uff0cDjango \u5141\u8bb8\u4f60\u6307\u5b9a\u4e00\u4e2a\u4e2d\u4ecb\u6a21\u578b\u6765\u5b9a\u4e49\u591a\u5bf9\u591a\u5173\u7cfb\u3002 \u4f60\u53ef\u4ee5\u5c06\u5176\u4ed6\u5b57\u6bb5\u653e\u5728\u4e2d\u4ecb\u6a21\u578b\u91cc\u9762\u3002\u6e90\u6a21\u578b\u7684ManyToManyField \u5b57\u6bb5\u5c06\u4f7f\u7528through \u53c2\u6570\u6307\u5411\u4e2d\u4ecb\u6a21\u578b\u3002\u5bf9\u4e8e\u4e0a\u9762\u7684\u97f3\u4e50\u5c0f\u7ec4\u7684\u4f8b\u5b50\uff0c\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n<pre><code class=\"language-yaml\">from django.db import models\n\nclass Person(models.Model):\n    name = models.CharField(max_length=128)\n\n    def __str__(self):              # __unicode__ on Python 2\n        return self.name\n\nclass Group(models.Model):\n    name = models.CharField(max_length=128)\n    members = models.ManyToManyField(Person, through=&#039;Membership&#039;)\n\n    def __str__(self):              # __unicode__ on Python 2\n        return self.name\n\nclass Membership(models.Model):\n    person = models.ForeignKey(Person)\n    group = models.ForeignKey(Group)\n    date_joined = models.DateField()\n    invite_reason = models.CharField(max_length=64)\n<\/code><\/pre>\n<p>\u65e2\u7136\u4f60\u5df2\u7ecf\u8bbe\u7f6e\u597dManyToManyField \u6765\u4f7f\u7528\u4e2d\u4ecb\u6a21\u578b\uff08\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\u5c31\u662fMembership\uff09\uff0c\u63a5\u4e0b\u6765\u4f60\u8981\u5f00\u59cb\u521b\u5efa\u591a\u5bf9\u591a\u5173\u7cfb\u3002\u4f60\u8981\u505a\u7684\u5c31\u662f\u521b\u5efa\u4e2d\u4ecb\u6a21\u578b\u7684\u5b9e\u4f8b\uff1a<\/p>\n<pre><code class=\"language-yaml\">>&gt;&gt; ringo = Person.objects.create(name=&quot;Ringo Starr&quot;)\n>&gt;&gt; paul = Person.objects.create(name=&quot;Paul McCartney&quot;)\n>&gt;&gt; beatles = Group.objects.create(name=&quot;The Beatles&quot;)\n>&gt;&gt; m1 = Membership(person=ringo, group=beatles,\n...     date_joined=date(1962, 8, 16),\n...     invite_reason=&quot;Needed a new drummer.&quot;)\n>&gt;&gt; m1.save()\n>&gt;&gt; beatles.members.all()\n[&lt;Person: Ringo Starr&gt;]\n>&gt;&gt; ringo.group_set.all()\n[&lt;Group: The Beatles&gt;]\n>&gt;&gt; m2 = Membership.objects.create(person=paul, group=beatles,\n...     date_joined=date(1960, 8, 1),\n...     invite_reason=&quot;Wanted to form a band.&quot;)\n>&gt;&gt; beatles.members.all()\n[&lt;Person: Ringo Starr&gt;, &lt;Person: Paul McCartney&gt;]\n<\/code><\/pre>\n<p>\u4e0e\u666e\u901a\u7684\u591a\u5bf9\u591a\u5b57\u6bb5\u4e0d\u540c\uff0c\u4f60\u4e0d\u80fd\u4f7f\u7528add\u3001 create\u548c\u8d4b\u503c\u8bed\u53e5\uff08\u6bd4\u5982\uff0cbeatles.members = [&#8230;]\uff09\u6765\u521b\u5efa\u5173\u7cfb\uff1a<\/p>\n<pre><code class=\"language-yaml\"># THIS WILL NOT WORK\n>&gt;&gt; beatles.members.add(john)\n# NEITHER WILL THIS\n>&gt;&gt; beatles.members.create(name=&quot;George Harrison&quot;)\n# AND NEITHER WILL THIS\n>&gt;&gt; beatles.members = [john, paul, ringo, george]<\/code><\/pre>\n<p>\u4e3a\u4ec0\u4e48\u4e0d\u80fd\u8fd9\u6837\u505a\uff1f \u8fd9\u662f\u56e0\u4e3a\u4f60\u4e0d\u80fd\u53ea\u521b\u5efa Person\u548c Group\u4e4b\u95f4\u7684\u5173\u8054\u5173\u7cfb\uff0c\u4f60\u8fd8\u8981\u6307\u5b9a Membership\u6a21\u578b\u4e2d\u6240\u9700\u8981\u7684\u6240\u6709\u4fe1\u606f\uff1b\u800c\u7b80\u5355\u7684add\u3001create \u548c\u8d4b\u503c\u8bed\u53e5\u662f\u505a\u4e0d\u5230\u8fd9\u4e00\u70b9\u7684\u3002\u6240\u4ee5\u5b83\u4eec\u4e0d\u80fd\u5728\u4f7f\u7528\u4e2d\u4ecb\u6a21\u578b\u7684\u591a\u5bf9\u591a\u5173\u7cfb\u4e2d\u4f7f\u7528\u3002\u6b64\u65f6\uff0c\u552f\u4e00\u7684\u529e\u6cd5\u5c31\u662f\u521b\u5efa\u4e2d\u4ecb\u6a21\u578b\u7684\u5b9e\u4f8b\u3002<\/p>\n<p>remove()\u65b9\u6cd5\u88ab\u7981\u7528\u4e5f\u662f\u51fa\u4e8e\u540c\u6837\u7684\u539f\u56e0\u3002\u4f46\u662fclear() \u65b9\u6cd5\u5374\u662f\u53ef\u7528\u7684\u3002\u5b83\u53ef\u4ee5\u6e05\u7a7a\u67d0\u4e2a\u5b9e\u4f8b\u6240\u6709\u7684\u591a\u5bf9\u591a\u5173\u7cfb\uff1a<\/p>\n<pre><code class=\"language-yaml\">>&gt;&gt; # Beatles have broken up\n>&gt;&gt; beatles.members.clear()\n>&gt;&gt; # Note that this deletes the intermediate model instances\n>&gt;&gt; Membership.objects.all()\n[]<\/code><\/pre>\n<h2>\u4e09 \u67e5\u8be2\u4f18\u5316<\/h2>\n<h3>3.1\u8868\u6570\u636e<\/h3>\n<div id=\"rml_readmorelogin_placeholder\" style=\"position:relative;\"><div id=\"rml_fade_content\" style=\"position: absolute;\r\ntop:-10em;\r\nwidth:100%;\r\nheight:10em;\r\nbackground: -webkit-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -moz-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -o-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\r\nbackground-image: -ms-linear-gradient(rgba(255, 255, 255, 0) 0%,#ffffff 100%);\"><\/div><div class=\"wpf-controller aru_rml_from_in_post\" style=\"background-color:#eeeeee;border:5px solid #cce6ff;\" id=\"ARU_ReadMoreLogin_ReadMoreLoginController\"><h2 id=\"Header\">\u67e5\u770b\u66f4\u591a<\/h2><div id=\"Message\"><p>\u8054\u7cfb\u7ba1\u7406\u5458\u5fae\u4fe1tutu19192010\uff0c\u6ce8\u518c\u8d26\u53f7<\/p>\n<\/div><div id=\"StatusBarHeader\"><\/div><form id=\"ARU_ReadMoreLogin_ReadMoreLoginController\"><input name=\"post_id\" value=\"5779\" type=\"hidden\"\/><input name=\"_init_callback\" value=\"InitLogin\" type=\"hidden\"\/><input name=\"post_id\" value=\"5779\" type=\"hidden\"\/><input name=\"rt_ype\" value=\"1\" type=\"hidden\"\/><input name=\"nonce\" value=\"c9c8100a3b\" type=\"hidden\"\/><input name=\"_wpnonce\" value=\"b0e6d8f8bf\" type=\"hidden\"\/><input name=\"_controller\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginController\" type=\"hidden\"\/><input name=\"_proxy_controller\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginController\" type=\"hidden\"\/><input name=\"_view\" value=\"ARU_ReadMoreLogin\\ReadMoreLoginView\" type=\"hidden\"\/><table class=\"wpf-table-placeholder\"><tbody class=\"wpf-table-placeholder\"><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\" width=\"400px\"><table class=\"wpf-table-placeholder\"><tbody class=\"wpf-table-placeholder\"><tr class=\"wpf-table-placeholder\"><th class=\"wpf-table-placeholder-input\"><label class=\"wpf-label\">Username:<\/label><\/th><\/tr><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\"><input class=\"regular-text text_input\" name=\"username\" value=\"\" type=\"text\"\/><\/td><\/tr><tr class=\"wpf-table-placeholder\"><th class=\"wpf-table-placeholder-input\"><label class=\"wpf-label\">Password:<\/label><\/th><\/tr><tr class=\"wpf-table-placeholder\"><td class=\"wpf-table-placeholder-input\"><input class=\"regular-text text_input\" name=\"password\" value=\"\" type=\"password\"\/><\/td><\/tr><\/tbody><\/table><p class=\"wpf-table-placeholder submit\"><button class=\"wp_plugin_framework_ajax_button\" type=\"button\" style=\"background-color:#4D90FE;;color:#ffffff;;border:1px solid #3079ed;\" name=\"_event\" value=\"ButtonLogin\">Log in<\/button><\/p><\/td><td class=\"wpf-table-placeholder-input\"><\/td><\/tr><\/tbody><\/table><\/form><div id=\"ButtonStartRegister\"><a href=\"https:\/\/egonlin.com\/wp-login.php?action=register\">Register<\/a><\/div><div id=\"Link1\"><a href=\"https:\/\/egonlin.com\/wp-login.php?action=lostpassword\">Forgotten username or password?<\/a><\/div><div id=\"StatusBarFooter\"><\/div><\/div><\/div><div id=aru_remaining_content><\/div>","protected":false},"excerpt":{"rendered":"<p>Django-model\u8fdb\u9636 \u4e00 QuerySet\u5bf9\u8c61 1.1\u53ef\u5207\u7247 \u4f7f\u7528Python \u7684\u5207\u7247\u8bed\u6cd5\u6765\u9650\u5236\u67e5\u8be2\u96c6 [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[385,389],"tags":[],"_links":{"self":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/5779"}],"collection":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5779"}],"version-history":[{"count":0,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/5779\/revisions"}],"wp:attachment":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5779"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5779"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5779"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}