{"id":20357,"date":"2024-01-02T04:50:23","date_gmt":"2024-01-02T04:50:23","guid":{"rendered":"https:\/\/server.hk\/blog\/20357\/"},"modified":"2024-11-14T10:39:51","modified_gmt":"2024-11-14T02:39:51","slug":"postgresql-command-create-trigger","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/20357\/","title":{"rendered":"PostgreSQL \u6307\u4ee4\uff1aCREATE TRIGGER"},"content":{"rendered":"<h1 id=\"postgresql-command-create-trigger-vOVkOGvpdW\">PostgreSQL \u6307\u4ee4\uff1aCREATE TRIGGER<\/h1>\n<p>PostgreSQL \u662f\u4e00\u500b\u529f\u80fd\u5f37\u5927\u7684\u958b\u6e90\u95dc\u806f\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u63d0\u4f9b\u5ee3\u6cdb\u7684\u529f\u80fd\u548c\u7279\u6027\u3002\u5176\u4e2d\u4e00\u500b\u95dc\u9375\u7279\u6027\u662f\u80fd\u5920\u5275\u5efa\u89f8\u767c\u5668\uff0c\u9019\u662f\u4e00\u7a2e\u7279\u6b8a\u985e\u578b\u7684\u5132\u5b58\u904e\u7a0b\uff0c\u6703\u5728\u7279\u5b9a\u4e8b\u4ef6\u6216\u5c0d\u8868\u683c\u57f7\u884c\u7684\u64cd\u4f5c\u6642\u81ea\u52d5\u57f7\u884c\u3002\u5728\u672c\u6587\u4e2d\uff0c\u6211\u5011\u5c07\u63a2\u8a0e PostgreSQL \u6307\u4ee4 <code>CREATE TRIGGER<\/code> \u53ca\u5176\u5404\u500b\u65b9\u9762\u3002<\/p>\n<h2 id=\"what-is-a-trigger-vOVkOGvpdW\">\u4ec0\u9ebc\u662f\u89f8\u767c\u5668\uff1f<\/h2>\n<p>\u89f8\u767c\u5668\u662f\u4e00\u7a2e\u8207\u8868\u683c\u76f8\u95dc\u806f\u7684\u8cc7\u6599\u5eab\u5c0d\u8c61\uff0c\u7576\u7279\u5b9a\u4e8b\u4ef6\u767c\u751f\u6642\u81ea\u52d5\u57f7\u884c\u3002\u9019\u4e9b\u4e8b\u4ef6\u53ef\u4ee5\u5305\u62ec\u5c0d\u8868\u683c\u7684 INSERT\u3001UPDATE \u6216 DELETE \u64cd\u4f5c\u3002\u89f8\u767c\u5668\u5c0d\u65bc\u5f37\u5236\u6578\u64da\u5b8c\u6574\u6027\u3001\u5be6\u65bd\u8907\u96dc\u7684\u696d\u52d9\u898f\u5247\u3001\u5be9\u8a08\u8b8a\u66f4\u4ee5\u53ca\u57f7\u884c\u5176\u4ed6\u81ea\u52d5\u5316\u4efb\u52d9\u975e\u5e38\u6709\u7528\u3002<\/p>\n<h2 id=\"creating-a-trigger-vOVkOGvpdW\">\u5275\u5efa\u89f8\u767c\u5668<\/h2>\n<p><code>CREATE TRIGGER<\/code> \u6307\u4ee4\u7528\u65bc\u5728 PostgreSQL \u4e2d\u5275\u5efa\u89f8\u767c\u5668\u3002\u4ee5\u4e0b\u662f\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>CREATE TRIGGER trigger_name\r\n    {BEFORE | AFTER | INSTEAD OF} {event [OR ...]}\r\n    ON table_name\r\n    [FOR [EACH] {ROW | STATEMENT}]\r\n    EXECUTE FUNCTION function_name();\r\n<\/code><\/pre>\n<p>\u8b93\u6211\u5011\u5206\u89e3\u4e00\u4e0b\u8a9e\u6cd5\uff1a<\/p>\n<ul>\n<li><code>trigger_name<\/code>\uff1a\u89f8\u767c\u5668\u7684\u540d\u7a31\u3002<\/li>\n<li><code>BEFORE | AFTER | INSTEAD OF<\/code>\uff1a\u6307\u5b9a\u89f8\u767c\u5668\u4f55\u6642\u88ab\u89f8\u767c\u3002<code>BEFORE<\/code> \u89f8\u767c\u5668\u5728\u4e8b\u4ef6\u4e4b\u524d\u57f7\u884c\uff0c<code>AFTER<\/code> \u89f8\u767c\u5668\u5728\u4e8b\u4ef6\u4e4b\u5f8c\u57f7\u884c\uff0c\u800c <code>INSTEAD OF<\/code> \u89f8\u767c\u5668\u5247\u662f\u5728\u4e8b\u4ef6\u767c\u751f\u6642\u57f7\u884c\u3002<\/li>\n<li><code>event<\/code>\uff1a\u89f8\u767c\u89f8\u767c\u5668\u57f7\u884c\u7684\u4e8b\u4ef6\uff0c\u5982 <code>INSERT<\/code>\u3001<code>UPDATE<\/code> \u6216 <code>DELETE<\/code>\u3002<\/li>\n<li><code>table_name<\/code>\uff1a\u89f8\u767c\u5668\u5275\u5efa\u7684\u8868\u683c\u540d\u7a31\u3002<\/li>\n<li><code>FOR [EACH] {ROW | STATEMENT}<\/code>\uff1a\u6307\u5b9a\u89f8\u767c\u5668\u662f\u5c0d\u53d7\u4e8b\u4ef6\u5f71\u97ff\u7684\u6bcf\u4e00\u884c\u57f7\u884c\uff08<code>ROW<\/code>\uff09\uff0c\u9084\u662f\u5c0d\u6bcf\u500b\u8a9e\u53e5\u57f7\u884c\u4e00\u6b21\uff0c\u4e0d\u8ad6\u53d7\u5f71\u97ff\u7684\u884c\u6578\uff08<code>STATEMENT<\/code>\uff09\u3002<\/li>\n<li><code>function_name()<\/code>\uff1a\u7576\u89f8\u767c\u5668\u88ab\u89f8\u767c\u6642\u57f7\u884c\u7684\u51fd\u6578\u540d\u7a31\u3002<\/li>\n<\/ul>\n<h2 id=\"example-vOVkOGvpdW\">\u793a\u4f8b<\/h2>\n<p>\u8b93\u6211\u5011\u8003\u616e\u4e00\u500b\u793a\u4f8b\uff0c\u6211\u5011\u5e0c\u671b\u5275\u5efa\u4e00\u500b\u89f8\u767c\u5668\uff0c\u7576\u5c0d\u540d\u70ba <code>employees<\/code> \u7684\u8868\u683c\u57f7\u884c\u66f4\u65b0\u64cd\u4f5c\u6642\uff0c\u81ea\u52d5\u66f4\u65b0\u884c\u7684\u6700\u5f8c\u4fee\u6539\u6642\u9593\u6233\u3002\u4ee5\u4e0b\u662f\u5275\u5efa\u89f8\u767c\u5668\u7684\u65b9\u6cd5\uff1a<\/p>\n<pre><code>CREATE TRIGGER update_timestamp\r\n    BEFORE UPDATE\r\n    ON employees\r\n    FOR EACH ROW\r\n    EXECUTE FUNCTION update_timestamp_function();\r\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u793a\u4f8b\u4e2d\uff0c\u89f8\u767c\u5668\u540d\u70ba <code>update_timestamp<\/code>\uff0c\u4e26\u5728\u5c0d <code>employees<\/code> \u8868\u683c\u9032\u884c\u66f4\u65b0\u64cd\u4f5c\u4e4b\u524d\u89f8\u767c\u3002\u5b83\u6703\u5c0d\u6bcf\u4e00\u884c\u53d7\u66f4\u65b0\u64cd\u4f5c\u5f71\u97ff\u7684\u884c\u57f7\u884c\u3002\u8a72\u89f8\u767c\u5668\u8abf\u7528\u540d\u70ba <code>update_timestamp_function()<\/code> \u7684\u51fd\u6578\uff0c\u8a72\u51fd\u6578\u8ca0\u8cac\u66f4\u65b0\u6700\u5f8c\u4fee\u6539\u6642\u9593\u6233\u3002<\/p>\n<h2 id=\"summary-vOVkOGvpdW\">\u7e3d\u7d50<\/h2>\n<p>PostgreSQL \u7684 <code>CREATE TRIGGER<\/code> \u6307\u4ee4\u5141\u8a31\u60a8\u5275\u5efa\u89f8\u767c\u5668\uff0c\u9019\u4e9b\u89f8\u767c\u5668\u6703\u81ea\u52d5\u57f7\u884c\u4ee5\u97ff\u61c9\u8868\u683c\u4e0a\u7684\u7279\u5b9a\u4e8b\u4ef6\u3002\u89f8\u767c\u5668\u662f\u5f37\u5927\u7684\u5de5\u5177\uff0c\u7528\u65bc\u5f37\u5236\u6578\u64da\u5b8c\u6574\u6027\u3001\u5be6\u65bd\u696d\u52d9\u898f\u5247\u548c\u57f7\u884c\u81ea\u52d5\u5316\u4efb\u52d9\u3002\u901a\u904e\u4f7f\u7528 <code>CREATE TRIGGER<\/code> \u6307\u4ee4\uff0c\u60a8\u53ef\u4ee5\u5145\u5206\u5229\u7528 PostgreSQL \u7684\u89f8\u767c\u5668\u529f\u80fd\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u53ef\u9760\u7684 VPS \u4e3b\u6a5f\u63d0\u4f9b\u5546\u4f86\u904b\u884c\u60a8\u7684 PostgreSQL \u8cc7\u6599\u5eab\uff0c\u8003\u616e <a href=\"https:\/\/server.hk\">Server.HK<\/a>\u3002\u901a\u904e\u4ed6\u5011\u7684\u9ad8\u7d1a VPS \u89e3\u6c7a\u65b9\u6848\uff0c\u60a8\u53ef\u4ee5\u78ba\u4fdd PostgreSQL \u74b0\u5883\u7684\u6700\u4f73\u6027\u80fd\u548c\u53ef\u9760\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>PostgreSQL \u6307\u4ee4\uff1aCR&#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-20357","post","type-post","status-publish","format-standard","hentry","category-setup-tutorials"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20357","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=20357"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20357\/revisions"}],"predecessor-version":[{"id":24399,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/20357\/revisions\/24399"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=20357"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=20357"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=20357"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}