{"id":20343,"date":"2024-01-02T04:36:23","date_gmt":"2024-01-02T04:36:23","guid":{"rendered":"https:\/\/server.hk\/blog\/20343\/"},"modified":"2024-11-14T10:40:06","modified_gmt":"2024-11-14T02:40:06","slug":"postgresql-command-alter-table","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/20343\/","title":{"rendered":"PostgreSQL \u6307\u4ee4\uff1aALTER TABLE"},"content":{"rendered":"

PostgreSQL \u6307\u4ee4\uff1aALTER TABLE<\/h1>\n

PostgreSQL \u662f\u4e00\u500b\u529f\u80fd\u5f37\u5927\u4e14\u7279\u6027\u8c50\u5bcc\u7684\u958b\u6e90\u95dc\u806f\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u3002\u5b83\u63d0\u4f9b\u5ee3\u6cdb\u7684\u6307\u4ee4\u548c\u529f\u80fd\u4f86\u7ba1\u7406\u548c\u64cd\u4f5c\u8cc7\u6599\u5eab\u8868\u683c\u3002\u5176\u4e2d\u4e00\u500b\u6307\u4ee4\u662f ALTER TABLE<\/code> \u6307\u4ee4\uff0c\u8a72\u6307\u4ee4\u5141\u8a31\u60a8\u4fee\u6539\u73fe\u6709\u8868\u683c\u7684\u7d50\u69cb\u3002<\/p>\n

\u4fee\u6539\u8868\u683c\u5217<\/h2>\n

ALTER TABLE<\/code> \u6307\u4ee4\u53ef\u4ee5\u7528\u4f86\u65b0\u589e\u3001\u4fee\u6539\u6216\u522a\u9664\u73fe\u6709\u8868\u683c\u4e2d\u7684\u5217\u3002\u8b93\u6211\u5011\u63a2\u8a0e\u4e00\u4e9b\u5e38\u898b\u7684\u4f7f\u7528\u6848\u4f8b\uff1a<\/p>\n

\u65b0\u589e\u5217<\/h3>\n

\u8981\u5411\u73fe\u6709\u8868\u683c\u6dfb\u52a0\u65b0\u5217\uff0c\u53ef\u4ee5\u4f7f\u7528 ADD COLUMN<\/code> \u5b50\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n

ALTER TABLE employees\r\nADD COLUMN email VARCHAR(255);\r\n<\/code><\/pre>\n
\u9019\u689d\u6307\u4ee4\u5411 employees<\/code> \u8868\u683c\u4e2d\u65b0\u589e\u4e86\u4e00\u500b\u540d\u70ba email<\/code> \u7684\u5217\uff0c\u985e\u578b\u70ba VARCHAR(255)<\/code>\u3002<\/p>\n
\u4fee\u6539\u5217<\/h3>\n
\u5982\u679c\u9700\u8981\u4fee\u6539\u73fe\u6709\u5217\u7684\u6578\u64da\u985e\u578b\u6216\u7d04\u675f\uff0c\u53ef\u4ee5\u4f7f\u7528 ALTER COLUMN<\/code> \u5b50\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
ALTER TABLE employees\r\nALTER COLUMN email SET NOT NULL;\r\n<\/code><\/pre>\n
\u9019\u689d\u6307\u4ee4\u4fee\u6539\u4e86 employees<\/code> \u8868\u683c\u4e2d\u7684 email<\/code> \u5217\uff0c\u4e26\u8a2d\u7f6e\u70ba NOT NULL<\/code>\uff0c\u9019\u610f\u5473\u8457\u8a72\u5217\u4e0d\u80fd\u5305\u542b\u7a7a\u503c\u3002<\/p>\n
\u522a\u9664\u5217<\/h3>\n
\u8981\u5f9e\u8868\u683c\u4e2d\u522a\u9664\u4e00\u5217\uff0c\u53ef\u4ee5\u4f7f\u7528 DROP COLUMN<\/code> \u5b50\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
ALTER TABLE employees\r\nDROP COLUMN email;\r\n<\/code><\/pre>\n
\u9019\u689d\u6307\u4ee4\u5f9e employees<\/code> \u8868\u683c\u4e2d\u522a\u9664\u4e86 email<\/code> \u5217\u3002<\/p>\n
\u4fee\u6539\u8868\u683c\u7d04\u675f<\/h2>\n
\u9664\u4e86\u4fee\u6539\u5217\u4e4b\u5916\uff0cALTER TABLE<\/code> \u6307\u4ee4\u9084\u53ef\u4ee5\u7528\u65bc\u6dfb\u52a0\u3001\u4fee\u6539\u6216\u522a\u9664\u8868\u683c\u4e0a\u7684\u7d04\u675f\u3002<\/p>\n
\u65b0\u589e\u7d04\u675f<\/h3>\n
\u8981\u5411\u8868\u683c\u6dfb\u52a0\u65b0\u7684\u7d04\u675f\uff0c\u53ef\u4ee5\u4f7f\u7528 ADD CONSTRAINT<\/code> \u5b50\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
ALTER TABLE employees\r\nADD CONSTRAINT pk_employees PRIMARY KEY (id);\r\n<\/code><\/pre>\n
\u9019\u689d\u6307\u4ee4\u5411 employees<\/code> \u8868\u683c\u6dfb\u52a0\u4e86\u4e00\u500b\u540d\u70ba pk_employees<\/code> \u7684\u4e3b\u9375\u7d04\u675f\uff0c\u4f7f\u7528 id<\/code> \u5217\u4f5c\u70ba\u4e3b\u9375\u3002<\/p>\n
\u4fee\u6539\u7d04\u675f<\/h3>\n
\u5982\u679c\u9700\u8981\u4fee\u6539\u73fe\u6709\u7684\u7d04\u675f\uff0c\u53ef\u4ee5\u4f7f\u7528 ALTER CONSTRAINT<\/code> \u5b50\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
ALTER TABLE employees\r\nALTER CONSTRAINT pk_employees RENAME TO pk_emp;\r\n<\/code><\/pre>\n
\u9019\u689d\u6307\u4ee4\u5c07 employees<\/code> \u8868\u683c\u4e2d\u7684 pk_employees<\/code> \u7d04\u675f\u91cd\u547d\u540d\u70ba pk_emp<\/code>\u3002<\/p>\n
\u522a\u9664\u7d04\u675f<\/h3>\n
\u8981\u5f9e\u8868\u683c\u4e2d\u522a\u9664\u7d04\u675f\uff0c\u53ef\u4ee5\u4f7f\u7528 DROP CONSTRAINT<\/code> \u5b50\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
ALTER TABLE employees\r\nDROP CONSTRAINT pk_emp;\r\n<\/code><\/pre>\n
\u9019\u689d\u6307\u4ee4\u5f9e employees<\/code> \u8868\u683c\u4e2d\u522a\u9664\u4e86 pk_emp<\/code> \u7d04\u675f\u3002<\/p>\n
\u7d50\u8ad6<\/h2>\n
PostgreSQL \u4e2d\u7684 ALTER TABLE<\/code> \u6307\u4ee4\u63d0\u4f9b\u4e86\u4e00\u7a2e\u9748\u6d3b\u4e14\u5f37\u5927\u7684\u65b9\u5f0f\u4f86\u4fee\u6539\u73fe\u6709\u8cc7\u6599\u5eab\u8868\u683c\u7684\u7d50\u69cb\u3002\u7121\u8ad6\u60a8\u9700\u8981\u6dfb\u52a0\u3001\u4fee\u6539\u6216\u522a\u9664\u5217\u6216\u7d04\u675f\uff0cPostgreSQL \u90fd\u63d0\u4f9b\u4e86\u5ee3\u6cdb\u7684\u9078\u9805\u4f86\u6eff\u8db3\u60a8\u7684\u9700\u6c42\u3002<\/p>\n
\u5982\u9700\u4e86\u89e3\u6709\u95dc VPS \u4e3b\u6a5f\u89e3\u6c7a\u65b9\u6848\u7684\u66f4\u591a\u4fe1\u606f\uff0c\u8acb\u8a2a\u554f Server.HK<\/a>\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
PostgreSQL \u6307\u4ee4\uff1aAL...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4924],"tags":[],"class_list":["post-20343","post","type-post","status-publish","format-standard","hentry","category-setup-tutorials"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20343","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=20343"}],"version-history":[{"count":2,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20343\/revisions"}],"predecessor-version":[{"id":24414,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20343\/revisions\/24414"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=20343"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=20343"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=20343"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}