{"id":2966,"date":"2016-11-24T19:45:59","date_gmt":"2016-11-24T11:45:59","guid":{"rendered":"http:\/\/ixyzero.com\/blog\/?p=2966"},"modified":"2016-11-24T19:45:59","modified_gmt":"2016-11-24T11:45:59","slug":"django%e7%9a%84orm%e4%bd%bf%e7%94%a8%e8%ae%b0%e5%bd%95","status":"publish","type":"post","link":"https:\/\/ixyzero.com\/blog\/archives\/2966.html","title":{"rendered":"Django\u7684ORM\u4f7f\u7528\u8bb0\u5f55"},"content":{"rendered":"<p>=Start=<\/p>\n<h4>\u7f18\u7531\uff1a<\/h4>\n<p>\u56e0\u4e3a\u56e2\u961f\u91cc\u73b0\u5728\u90fd\u5728\u7528Django\u4f5c\u4e3aWeb\u5f00\u53d1\u6846\u67b6\uff08Flask\u867d\u7136\u7b80\u5355\u3001\u8f7b\u91cf\uff0c\u4f46\u5e76\u4e0d\u9002\u5408\u56e2\u961f\u534f\u4f5c\u5f00\u53d1\uff09\uff0c\u6240\u4ee5\u6700\u8fd1\u6211\u7684\u4e3b\u8981\u4efb\u52a1\u4e4b\u4e00\u5c31\u662f\u628a\u4e4b\u524d\u7528Flask\u5199\u7684Web\u5e94\u7528\u5f80Django\u4e0a\u8fc1\u79fb\uff0c\u867d\u7136\u4e4b\u524d\u7528\u8fc7\u4e00\u6bb5\u65f6\u95f4\u7684Django\uff0c\u4f46\u5e76\u4e0d\u719f\u6089\uff0c\u8fd9\u6b21\u5c31\u60f3\u7740\u5728\u8fc1\u79fb\u7684\u8fc7\u7a0b\u4e2d\u8bb0\u5f55\u4e00\u4e0b\u5927\u4f53\u8fc7\u7a0b\uff0c\u52a0\u6df1\u5370\u8c61\uff0c\u4e5f\u4e3a\u65b9\u4fbf\u4ee5\u540e\u53c2\u8003\u3002<\/p>\n<h4>\u6b63\u6587\uff1a<\/h4>\n<h5>0.\u4f7f\u7528MySQL\u6570\u636e\u5e93<\/h5>\n<p>\u5148\u5b89\u88c5MySQLdb\u6a21\u5757\u4f5c\u4e3a\u5e95\u5c42\u9a71\u52a8\uff08\u9700\u8981\u5148\u5b89\u88c5MySQL\u7684\u4e00\u4e9b\u57fa\u7840\u5e93\uff09\uff1b<\/p>\n<pre class=\"lang:default decode:true\">(virtualenv) $ pip install MySQL-python<\/pre>\n<p>\u7136\u540e\u4fee\u6539\u9879\u76ee\u7684settings.py\u914d\u7f6e\u6570\u636e\u5e93\u8fde\u63a5\u4fe1\u606f\uff1b<\/p>\n<pre class=\"lang:default decode:true\"># Database\n# https:\/\/docs.djangoproject.com\/en\/1.8\/ref\/settings\/#databases\n# http:\/\/www.ziqiangxuetang.com\/django\/django-multi-database.html\nDATABASES = {\n    'default': {\n        'ENGINE': 'django.db.backends.sqlite3',\n        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),\n    },\n    'db1': {\n        'ENGINE': 'django.db.backends.mysql',\n        'NAME': 'dbname1',\n        'USER': 'your_db_user_name',\n        'PASSWORD': 'yourpassword',\n        \"HOST\": \"localhost\",\n    },\n    'db2': {\n        'ENGINE': 'django.db.backends.mysql',\n        'NAME': 'dbname2',\n        'USER': 'your_db_user_name',\n        'PASSWORD': 'yourpassword',\n        \"HOST\": \"localhost\",\n    },\n}\n\n# use multi-database in django\nDATABASE_ROUTERS = ['project_name.database_router.DatabaseAppsRouter']\nDATABASE_APPS_MAPPING = {\n    #'app_name':'database_name',\n    'app1': 'db1',\n    'app2': 'db2',\n}<\/pre>\n<p>\u9a8c\u8bc1\u6570\u636e\u5e93\u914d\u7f6e\u662f\u5426\u6210\u529f\uff08\u6ca1\u6709\u62a5\u9519\u5219\u8868\u793a\u6210\u529f\uff09\uff1a<\/p>\n<pre class=\"lang:default decode:true\">$ cd project_dir\n$ python manage.py shell\n&gt;&gt;&gt; import MySQLdb\n&gt;&gt;&gt; from django.db import connection\n&gt;&gt;&gt; cursor = connection.cursor()<\/pre>\n<h6><span style=\"color: #0000ff;\">\u5728Django\u4e2d\u4f7f\u7528MySQL\u6570\u636e\u5e93<\/span><\/h6>\n<ul>\n<li><a href=\"http:\/\/www.cnblogs.com\/wendoudou\/p\/mysql.html\">http:\/\/www.cnblogs.com\/wendoudou\/p\/mysql.html<\/a><\/li>\n<li><a href=\"https:\/\/shenxgan.gitbooks.io\/django\/content\/publish\/2015-07-13-django-mysql.html\">https:\/\/shenxgan.gitbooks.io\/django\/content\/publish\/2015-07-13-django-mysql.html<\/a><\/li>\n<li><a href=\"https:\/\/docs.djangoproject.com\/en\/1.8\/ref\/databases\/#connecting-to-the-database\">https:\/\/docs.djangoproject.com\/en\/1.8\/ref\/databases\/#connecting-to-the-database<\/a><\/li>\n<li><a href=\"http:\/\/stackoverflow.com\/questions\/25794121\/cant-install-python-mysql-on-os-x-10-10-yosemite\">http:\/\/stackoverflow.com\/questions\/25794121\/cant-install-python-mysql-on-os-x-10-10-yosemite<\/a><\/li>\n<\/ul>\n<h6><strong><span style=\"color: #0000ff;\">\u5728Django\u4e2d\u8fdb\u884c\u591a\u6570\u636e\u5e93\u7684\u8bbe\u7f6e<\/span><\/strong><\/h6>\n<ul>\n<li><a href=\"https:\/\/docs.djangoproject.com\/en\/1.8\/topics\/db\/multi-db\/\">https:\/\/docs.djangoproject.com\/en\/1.8\/topics\/db\/multi-db\/<\/a><\/li>\n<li><a href=\"http:\/\/stackoverflow.com\/questions\/18547468\/multiple-databases-and-multiple-models-in-django\">http:\/\/stackoverflow.com\/questions\/18547468\/multiple-databases-and-multiple-models-in-django<\/a><\/li>\n<li><a href=\"http:\/\/www.cnblogs.com\/livingintruth\/p\/3760958.html\">django \u9879\u76ee\u4e2d\u4f7f\u7528\u591a\u6570\u636e\u5e93 multiple databases<\/a><\/li>\n<li><a href=\"http:\/\/www.ziqiangxuetang.com\/django\/django-multi-database.html\">Django \u591a\u6570\u636e\u5e93\u8054\u7528<\/a><\/li>\n<\/ul>\n<h5>1.Django\u7684ORM\u4e4bModel<\/h5>\n<h6>\u4ece\u5934\u5f00\u59cb\u521b\u5efa\u65b0\u8868<\/h6>\n<ul>\n<li><a href=\"https:\/\/docs.djangoproject.com\/en\/1.8\/topics\/db\/models\/\">\u7f16\u5199models<\/a><\/li>\n<li><a href=\"http:\/\/www.ziqiangxuetang.com\/django\/django-models.html\">Django \u6a21\u578b\uff08\u6570\u636e\u5e93\uff09<\/a><\/li>\n<li><a href=\"http:\/\/www.ziqiangxuetang.com\/django\/django-custom-field.html\">Django \u81ea\u5b9a\u4e49Field<\/a><\/li>\n<\/ul>\n<h6>\u4f7f\u7528\u5df2\u6709\u7684\u6570\u636e\u8868<\/h6>\n<p>\u5728\u57fa\u4e8eDjango\u7684Web\u5e94\u7528\u4e2d\u53ef\u4ee5\u76f4\u8fdeMySQL\u8fdb\u800c\u64cd\u4f5cMySQL\u6570\u636e\u5e93\uff0c\u6bd4\u8f83\u7075\u6d3b\uff0c\u4f46\u662f\u4e5f\u6bd4\u8f83\u7e41\u7410\uff0c\u9700\u8981\u6ce8\u610f\u9632\u8303SQL\u6ce8\u5165\uff1b<\/p>\n<p>\u5176\u6b21\u53ef\u4ee5\u4f7f\u7528Django\u81ea\u8eab\u63d0\u4f9b\u7684ORM\uff08\u6bd4\u8d77SQLalchemy\u6765\u8bf4\u8981\u7b80\u5355\u4e00\u4e9b\uff09\uff0c\u4f46\u9700\u8981\u7f16\u5199models\uff0c\u5bf9\u4e8e\u5df2\u7ecf\u5b58\u5728\u7684\u6570\u636e\u5e93\u8868\uff0c\u53ef\u4ee5\u901a\u8fc7inspectdb\u547d\u4ee4\u6765\u81ea\u52a8\u751f\u6210models\uff0c\u6bd4\u8f83\u65b9\u4fbf\u300edjango create model from existing table\u300f\uff1a<\/p>\n<p>\u53c2\u8003\u89e3\u7b54\uff1a<\/p>\n<pre class=\"lang:default decode:true\">$ python manage.py inspectdb &gt; django_app\/models.py\n$ python manage.py migrate\n#\u53ef\u80fd\u4f1a\u51fa\u73b0\u300cA model can't have more than one AutoField.\u300d\u7684\u9519\u8bef\u63d0\u793a\uff0c\u6240\u4ee5\u9700\u8981\u7f16\u8f91models.py\uff0c\u5c06 AutoField \u90a3\u4e2a\u5b57\u6bb5\u8bbe\u7f6e\u6210\u300cprimary_key=True\u300d\n$ vim django_app\/models.py\n$ python manage.py migrate<\/pre>\n<p>\u53c2\u8003\u94fe\u63a5\uff1a<\/p>\n<ul>\n<li><a href=\"https:\/\/docs.djangoproject.com\/en\/1.10\/howto\/legacy-databases\/\">https:\/\/docs.djangoproject.com\/en\/1.10\/howto\/legacy-databases\/<\/a><\/li>\n<li><a href=\"http:\/\/stackoverflow.com\/questions\/1179469\/is-it-posible-to-generate-django-models-from-the-database\">http:\/\/stackoverflow.com\/questions\/1179469\/is-it-posible-to-generate-django-models-from-the-database<\/a><\/li>\n<li><a href=\"http:\/\/stackoverflow.com\/questions\/21683095\/want-to-use-my-existing-mysql-database-with-django\">http:\/\/stackoverflow.com\/questions\/21683095\/want-to-use-my-existing-mysql-database-with-django<\/a><\/li>\n<li><a href=\"http:\/\/blog.alarmchang.com\/?p=177\">http:\/\/blog.alarmchang.com\/?p=177<\/a><\/li>\n<li><a href=\"https:\/\/docs.djangoproject.com\/en\/1.8\/topics\/db\/models\/#automatic-primary-key-fields\">https:\/\/docs.djangoproject.com\/en\/1.8\/topics\/db\/models\/#automatic-primary-key-fields<\/a><\/li>\n<\/ul>\n<h5>2.Django\u7684ORM\u4e4bQuerySet<\/h5>\n<ul>\n<li>filter() \u00a0#\u8fc7\u6ee4\uff08\u4f46\u4e0d\u652f\u6301\u300c\u4e0d\u7b49\u4e8e\u300d\uff0c\u9700\u8981\u7528\u5230\u4e0b\u9762\u7684exclude()\u6216Q()\uff09<\/li>\n<li>exclude() \u00a0#\u6392\u9664<\/li>\n<li>Q() \u00a0#\u53ef\u7528\u6765\u505a\u4e00\u4e9b\u590d\u6742\u7684\u67e5\u8be2<\/li>\n<\/ul>\n<p>==<\/p>\n<ul>\n<li><a href=\"https:\/\/docs.djangoproject.com\/en\/1.8\/topics\/db\/queries\/#retrieving-objects\">Django ORM \u67e5\u8be2<\/a><\/li>\n<li><a href=\"https:\/\/docs.djangoproject.com\/en\/1.8\/topics\/db\/sql\/#performing-raw-queries\">\u539f\u751fSQL\u67e5\u8be2<\/a><\/li>\n<li><a href=\"https:\/\/www.oschina.net\/translate\/higher-level-query-api-django-orm\">\u5efa\u7acb\u4e00\u4e2a\u66f4\u9ad8\u7ea7\u522b\u7684\u67e5\u8be2 API\uff1a\u6b63\u786e\u4f7f\u7528Django ORM \u7684\u65b9\u5f0f<\/a><\/li>\n<li><a href=\"https:\/\/tutorial.djangogirls.org\/zh\/django_orm\/\">Django ORM \u548c QuerySets\uff08\u67e5\u8be2\u96c6\uff09<\/a><\/li>\n<li><a href=\"http:\/\/www.ziqiangxuetang.com\/django\/django-queryset-api.html\">Django QuerySet API<\/a><\/li>\n<\/ul>\n<h5>3.Django\u7684ORM\u5982\u4f55\u5b9e\u73b0\u300cgroup by\u300d<\/h5>\n<pre class=\"lang:default decode:true\">from django.db.models import Count\nMembers.objects.values('designation').annotate(dcount=Count('designation')).order_by('-dcount')\n\n\u7b49\u4ef7\u4e8e\uff1a\nSELECT designation, COUNT(designation) AS dcount FROM members GROUP BY designation ORDER BY dcount desc;<\/pre>\n<ul>\n<li><a href=\"http:\/\/stackoverflow.com\/questions\/629551\/how-to-query-as-group-by-in-django\">http:\/\/stackoverflow.com\/questions\/629551\/how-to-query-as-group-by-in-django<\/a><\/li>\n<li><a href=\"http:\/\/stackoverflow.com\/questions\/13403609\/how-to-group-by-and-aggregate-with-django\">http:\/\/stackoverflow.com\/questions\/13403609\/how-to-group-by-and-aggregate-with-django<\/a><\/li>\n<li><a href=\"http:\/\/stackoverflow.com\/questions\/327807\/django-equivalent-for-count-and-group-by\">http:\/\/stackoverflow.com\/questions\/327807\/django-equivalent-for-count-and-group-by<\/a><\/li>\n<\/ul>\n<h5>4.Django\u7684ORM\u4e4b\u6570\u636e\u8868\u66f4\u6539<\/h5>\n<p>\u6211\u4eec\u8bbe\u8ba1\u6570\u636e\u5e93\u7684\u65f6\u5019\uff0c\u65e9\u671f\u8bbe\u8ba1\u5b8c\u540e\uff0c\u540e\u671f\u4f1a\u53d1\u73b0\u4e0d\u5b8c\u5584\uff0c\u8981\u5bf9\u6570\u636e\u8868\u8fdb\u884c\u66f4\u6539\uff0c\u8fd9\u65f6\u5019\u5c31\u8981\u4e86\u89e3\u4e00\u4e0b\u300c<a href=\"http:\/\/www.ziqiangxuetang.com\/django\/django-schema-migration.html\">Django \u6570\u636e\u8868\u66f4\u6539<\/a>\u300d\u7684\u77e5\u8bc6\u3002<\/p>\n<p>=END=<\/p>\n","protected":false},"excerpt":{"rendered":"<p>=Start= \u7f18\u7531\uff1a \u56e0\u4e3a\u56e2\u961f\u91cc\u73b0\u5728\u90fd\u5728\u7528Django\u4f5c\u4e3aWeb\u5f00\u53d1\u6846\u67b6\uff08Flask\u867d\u7136\u7b80\u5355\u3001\u8f7b\u91cf\uff0c\u4f46\u5e76\u4e0d\u9002 [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14,23,7],"tags":[627,681],"class_list":["post-2966","post","type-post","status-publish","format-standard","hentry","category-database","category-knowledgebase-2","category-programing","tag-django","tag-orm"],"views":2885,"_links":{"self":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/2966","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/comments?post=2966"}],"version-history":[{"count":0,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/2966\/revisions"}],"wp:attachment":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/media?parent=2966"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/categories?post=2966"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/tags?post=2966"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}