{"id":20365,"date":"2024-01-02T04:58:22","date_gmt":"2024-01-02T04:58:22","guid":{"rendered":"https:\/\/server.hk\/blog\/20365\/"},"modified":"2024-11-14T10:39:44","modified_gmt":"2024-11-14T02:39:44","slug":"postgresql-command-drop-type","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/20365\/","title":{"rendered":"PostgreSQL \u6307\u4ee4\uff1aDROP TYPE"},"content":{"rendered":"<h1 id=\"postgresql-command-drop-type-mAOxETgxAr\">PostgreSQL \u6307\u4ee4\uff1aDROP TYPE<\/h1>\n<p>PostgreSQL \u662f\u4e00\u500b\u529f\u80fd\u5f37\u5927\u7684\u958b\u6e90\u95dc\u4fc2\u578b\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u63d0\u4f9b\u4e86\u5ee3\u6cdb\u7684\u529f\u80fd\u548c\u7279\u6027\u3002<code>DROP TYPE<\/code> \u662f PostgreSQL \u4e2d\u4e00\u500b\u91cd\u8981\u7684\u6307\u4ee4\uff0c\u5141\u8a31\u7528\u6236\u5f9e\u8cc7\u6599\u5eab\u4e2d\u79fb\u9664\u7528\u6236\u81ea\u5b9a\u7fa9\u7684\u8cc7\u6599\u985e\u578b\u3002<\/p>\n<h2 id=\"understanding-user-defined-data-types-mAOxETgxAr\">\u4e86\u89e3\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b<\/h2>\n<p>\u5728 PostgreSQL \u4e2d\uff0c\u7528\u6236\u53ef\u4ee5\u4f7f\u7528 <code>CREATE TYPE<\/code> \u6307\u4ee4\u4f86\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b\u3002\u9019\u4e9b\u81ea\u5b9a\u7fa9\u7684\u8cc7\u6599\u985e\u578b\u53ef\u4ee5\u57fa\u65bc\u73fe\u6709\u7684\u8cc7\u6599\u985e\u578b\uff0c\u4e5f\u53ef\u4ee5\u662f\u5168\u65b0\u7684\u985e\u578b\u3002\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b\u63d0\u4f9b\u4e86\u4e00\u7a2e\u66f4\u6709\u610f\u7fa9\u4e14\u66f4\u6709\u6548\u7684\u65b9\u5f0f\u4f86\u7d44\u7e54\u548c\u7d50\u69cb\u5316\u6578\u64da\u3002<\/p>\n<p>\u7136\u800c\uff0c\u6709\u6642\u5019\u53ef\u80fd\u4e0d\u518d\u9700\u8981\u67d0\u500b\u81ea\u5b9a\u7fa9\u7684\u8cc7\u6599\u985e\u578b\uff0c\u9019\u6642 <code>DROP TYPE<\/code> \u6307\u4ee4\u5c31\u6703\u6d3e\u4e0a\u7528\u5834\u3002<\/p>\n<h2 id=\"the-drop-type-command-syntax-mAOxETgxAr\">DROP TYPE \u6307\u4ee4\u8a9e\u6cd5<\/h2>\n<p><code>DROP TYPE<\/code> \u6307\u4ee4\u7684\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>DROP TYPE [IF EXISTS] type_name [, ...] [CASCADE | RESTRICT];\r\n<\/code><\/pre>\n<p>\u8b93\u6211\u5011\u4f86\u62c6\u89e3\u8a9e\u6cd5\u4e2d\u7684\u4e0d\u540c\u7d44\u6210\u90e8\u5206\uff1a<\/p>\n<ul>\n<li><code>IF EXISTS<\/code>\uff08\u53ef\u9078\uff09\uff1a\u6b64\u5b50\u53e5\u5141\u8a31\u60a8\u5728\u6307\u5b9a\u7684\u8cc7\u6599\u985e\u578b\u4e0d\u5b58\u5728\u6642\u907f\u514d\u5831\u932f\u3002<\/li>\n<li><code>type_name<\/code>\uff1a\u9019\u662f\u60a8\u60f3\u8981\u522a\u9664\u7684\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b\u7684\u540d\u7a31\u3002<\/li>\n<li><code>CASCADE | RESTRICT<\/code>\uff08\u53ef\u9078\uff09\uff1a\u9019\u662f\u8655\u7406\u4f9d\u8cf4\u7269\u4ef6\u7684\u5169\u500b\u9078\u9805\u3002\u6307\u5b9a <code>CASCADE<\/code> \u6642\uff0c\u6240\u6709\u4f9d\u8cf4\u8a72\u8cc7\u6599\u985e\u578b\u7684\u7269\u4ef6\u4e5f\u5c07\u88ab\u522a\u9664\u3002\u6307\u5b9a <code>RESTRICT<\/code> \u6642\uff0c\u5982\u679c\u5b58\u5728\u4f9d\u8cf4\u7269\u4ef6\uff0c\u5247\u8a72\u6307\u4ee4\u5c07\u5931\u6557\u3002<\/li>\n<\/ul>\n<h2 id=\"examples-mAOxETgxAr\">\u7bc4\u4f8b<\/h2>\n<p>\u8b93\u6211\u5011\u770b\u770b\u5e7e\u500b\u7bc4\u4f8b\u4f86\u4e86\u89e3 <code>DROP TYPE<\/code> \u6307\u4ee4\u7684\u904b\u4f5c\u65b9\u5f0f\uff1a<\/p>\n<h3 id=\"example-1-dropping-a-user-defined-data-type-mAOxETgxAr\">\u7bc4\u4f8b 1\uff1a\u522a\u9664\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>color<\/code> \u7684\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b\uff0c\u73fe\u5728\u6211\u5011\u60f3\u5c07\u5176\u5f9e\u8cc7\u6599\u5eab\u4e2d\u522a\u9664\u3002\u6211\u5011\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u6307\u4ee4\uff1a<\/p>\n<pre><code>DROP TYPE color;\r\n<\/code><\/pre>\n<p>\u6b64\u6307\u4ee4\u5c07\u6703\u5f9e\u8cc7\u6599\u5eab\u4e2d\u522a\u9664 <code>color<\/code> \u8cc7\u6599\u985e\u578b\u3002<\/p>\n<h3 id=\"example-2-dropping-a-user-defined-data-type-with-cascade-mAOxETgxAr\">\u7bc4\u4f8b 2\uff1a\u4f7f\u7528 CASCADE \u522a\u9664\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b<\/h3>\n<p>\u5982\u679c\u6709\u7269\u4ef6\u4f9d\u8cf4\u65bc\u8a72\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 <code>CASCADE<\/code> \u9078\u9805\u4f86\u9023\u540c\u4f9d\u8cf4\u7269\u4ef6\u4e00\u8d77\u522a\u9664\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>DROP TYPE color CASCADE;\r\n<\/code><\/pre>\n<p>\u6b64\u6307\u4ee4\u5c07\u522a\u9664 <code>color<\/code> \u8cc7\u6599\u985e\u578b\u4ee5\u53ca\u6240\u6709\u4f9d\u8cf4\u8a72\u8cc7\u6599\u985e\u578b\u7684\u7269\u4ef6\u3002<\/p>\n<h3 id=\"example-3-dropping-multiple-user-defined-data-types-mAOxETgxAr\">\u7bc4\u4f8b 3\uff1a\u522a\u9664\u591a\u500b\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b<\/h3>\n<p>\u60a8\u4e5f\u53ef\u4ee5\u5728\u4e00\u500b\u6307\u4ee4\u4e2d\u522a\u9664\u591a\u500b\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>DROP TYPE color, size, shape;\r\n<\/code><\/pre>\n<p>\u6b64\u6307\u4ee4\u5c07\u6703\u5f9e\u8cc7\u6599\u5eab\u4e2d\u522a\u9664 <code>color<\/code>\u3001<code>size<\/code> \u548c <code>shape<\/code> \u8cc7\u6599\u985e\u578b\u3002<\/p>\n<h2 id=\"summary-mAOxETgxAr\">\u6458\u8981<\/h2>\n<p>PostgreSQL \u4e2d\u7684 <code>DROP TYPE<\/code> \u6307\u4ee4\u5141\u8a31\u7528\u6236\u5f9e\u8cc7\u6599\u5eab\u4e2d\u79fb\u9664\u7528\u6236\u81ea\u5b9a\u7fa9\u7684\u8cc7\u6599\u985e\u578b\uff0c\u4e26\u63d0\u4f9b\u4e86\u4e00\u7a2e\u6e05\u7406\u4e0d\u518d\u9700\u8981\u7684\u8cc7\u6599\u985e\u578b\u7684\u65b9\u6cd5\u3002\u901a\u904e\u4f7f\u7528 <code>CASCADE<\/code> \u9078\u9805\uff0c\u60a8\u9084\u53ef\u4ee5\u9023\u540c\u4f9d\u8cf4\u7269\u4ef6\u4e00\u8d77\u522a\u9664\u8a72\u8cc7\u6599\u985e\u578b\u3002PostgreSQL \u5728\u7ba1\u7406\u7528\u6236\u81ea\u5b9a\u7fa9\u8cc7\u6599\u985e\u578b\u65b9\u9762\u7684\u9748\u6d3b\u6027\uff0c\u4f7f\u5176\u6210\u70ba\u958b\u767c\u8005\u548c\u8cc7\u6599\u5eab\u7ba1\u7406\u54e1\u7684\u5f37\u5927\u9078\u64c7\u3002<\/p>\n<p>\u5982\u9700\u66f4\u591a\u6709\u95dc VPS \u8a17\u7ba1\u89e3\u6c7a\u65b9\u6848\u7684\u4fe1\u606f\uff0c\u8acb\u8a2a\u554f <a href=\"https:\/\/server.hk\">Server.HK<\/a>\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>PostgreSQL \u6307\u4ee4\uff1aDR&#46;&#46;&#46;<\/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-20365","post","type-post","status-publish","format-standard","hentry","category-setup-tutorials"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20365","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=20365"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20365\/revisions"}],"predecessor-version":[{"id":24389,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20365\/revisions\/24389"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=20365"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=20365"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=20365"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}