{"id":204524,"date":"2025-05-29T08:02:39","date_gmt":"2025-05-29T00:02:39","guid":{"rendered":"https:\/\/server.hk\/cnblog\/204524\/"},"modified":"2025-05-29T08:02:39","modified_gmt":"2025-05-29T00:02:39","slug":"python-%e4%b8%8e-postgresql-%e6%8f%92%e5%85%a5%e6%95%b0%e6%8d%ae%e6%97%b6%ef%bc%8c%e5%a6%82%e4%bd%95%e4%bc%98%e9%9b%85%e5%9c%b0%e5%a4%84%e7%90%86%e7%a9%ba%e5%80%bc%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/204524\/","title":{"rendered":"Python \u4e0e PostgreSQL \u63d2\u5165\u6570\u636e\u65f6\uff0c\u5982\u4f55\u4f18\u96c5\u5730\u5904\u7406\u7a7a\u503c\uff1f"},"content":{"rendered":"<p><b><\/b>     <\/p>\n<h1>Python \u4e0e PostgreSQL \u63d2\u5165\u6570\u636e\u65f6\uff0c\u5982\u4f55\u4f18\u96c5\u5730\u5904\u7406\u7a7a\u503c\uff1f<\/h1>\n<p>\u4eca\u65e5\u4e0d\u80af\u57cb\u5934\uff0c\u660e\u65e5\u4f55\u4ee5\u62ac\u5934\uff01\u6bcf\u65e5\u4e00\u53e5\u52aa\u529b\u81ea\u5df1\u7684\u8bdd\u54c8\u54c8~\u54c8\u55bd\uff0c\u4eca\u5929\u6211\u5c06\u7ed9\u5927\u5bb6\u5e26\u6765\u4e00\u7bc7\uff0c\u4e3b\u8981\u5185\u5bb9\u662f\u8bb2\u89e3<span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\"><\/span>\u7b49\u7b49\uff0c\u611f\u5174\u8da3\u7684\u670b\u53cb\u53ef\u4ee5\u6536\u85cf\u6216\u8005\u6709\u66f4\u597d\u7684\u5efa\u8bae\u5728\u8bc4\u8bba\u63d0\u51fa\uff0c\u6211\u90fd\u4f1a\u8ba4\u771f\u770b\u7684\uff01\u5927\u5bb6\u4e00\u8d77\u8fdb\u6b65\uff0c\u4e00\u8d77\u5b66\u4e60\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241109\/1731157428672f5db4c7af2.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>postgresql + python \u63d2\u5165\u6570\u636e\u65f6\u5982\u4f55\u5904\u7406\u7a7a\u503c<\/strong><\/p>\n<p>\u5728\u7f16\u5199 sql \u8bed\u53e5\u6216\u4f7f\u7528 python \u5411 postgresql \u6570\u636e\u5e93\u63d2\u5165\u6570\u636e\u65f6\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u7a7a\u503c\u5904\u7406\u7684\u95ee\u9898\u3002<\/p>\n<p><strong>1. sql \u8bed\u53e5\u4e2d\u7684\u7a7a\u503c\u5904\u7406<\/strong><\/p>\n<p>\u7a7a\u503c\u5728 sql \u8bed\u53e5\u4e2d\u8868\u793a\u4e3a null\uff0c\u4f46\u5728 python \u4e2d\u53ef\u4ee5\u8868\u793a\u4e3a &#8220;&#8221;\u3002\u4e3a\u4e86\u5c06 &#8220;&#8221; \u66ff\u6362\u4e3a null\uff0c\u53ef\u4ee5\u5728\u63d2\u5165\u8bed\u53e5\u4e2d\u4f7f\u7528 coalesce \u51fd\u6570\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n<pre>insert into student (name, age) value(coalesce(\"\", null), 15);<\/pre>\n<p><strong>2. np.nan\u3001none<\/strong><\/p>\n<p>\u4e3a\u4e86\u5c06 dataframe \u4e2d\u7684 np.nan \u6216 none \u8f6c\u6362\u4e3a null\uff0c\u53ef\u4ee5\u4f7f\u7528 pandas.to_sql() \u65b9\u6cd5\u7684 nan \u53c2\u6570\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n<pre>data = pd.DataFrame({'name': [\"Alice\", \"Bob\", np.nan], 'age': [15, 16, None]})\ndata.to_sql('student', engine, if_exists='append', index=False, nan=np.nan)<\/pre>\n<p>\u89e3\u51b3\u4e86 np.nan \u548c none \u5728\u63d2\u5165\u65f6\u663e\u793a\u4e3a\u7a7a\u5b57\u7b26\u4e32\u7684\u95ee\u9898\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u300aPython \u4e0e PostgreSQL \u63d2\u5165\u6570\u636e\u65f6\uff0c\u5982\u4f55\u4f18\u96c5\u5730\u5904\u7406\u7a7a\u503c\uff1f\u300b\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u5173\u4e8e\u7684\u8d44\u6599\u8bf7\u5173\u6ce8\u516c\u4f17\u53f7\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Python \u4e0e Postgre&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-204524","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/204524","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=204524"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/204524\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=204524"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=204524"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=204524"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}