{"id":5751,"date":"2024-11-14T11:14:58","date_gmt":"2024-11-14T03:14:58","guid":{"rendered":"https:\/\/fwq.ai\/blog\/5751\/"},"modified":"2024-11-14T11:14:58","modified_gmt":"2024-11-14T03:14:58","slug":"oracle%e6%80%8e%e4%b9%88%e8%8e%b7%e5%8f%96%e5%ad%97%e6%ae%b5%e9%95%bf%e5%ba%a6","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/5751\/","title":{"rendered":"Oracle\u600e\u4e48\u83b7\u53d6\u5b57\u6bb5\u957f\u5ea6"},"content":{"rendered":"<blockquote><p>\n  \u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u65b9\u6cd5\u83b7\u53d6 oracle \u4e2d\u5b57\u6bb5\u957f\u5ea6\uff1a\u4f7f\u7528 select \u67e5\u8be2\uff1b\u4f7f\u7528 describe \u547d\u4ee4\uff1b\u4f7f\u7528 dbms_metadata \u5305\u3002\n<\/p><\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/202405\/30\/2024053022004318705.jpg\" class=\"aligncenter\" title=\"Oracle\u600e\u4e48\u83b7\u53d6\u5b57\u6bb5\u957f\u5ea6\u63d2\u56fe\" alt=\"Oracle\u600e\u4e48\u83b7\u53d6\u5b57\u6bb5\u957f\u5ea6\u63d2\u56fe\" \/><\/p>\n<p><strong>\u5982\u4f55\u83b7\u53d6 Oracle \u4e2d\u5b57\u6bb5\u7684\u957f\u5ea6<\/strong><\/p>\n<p>\u5728 Oracle \u6570\u636e\u5e93\u4e2d\uff0c\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u65b9\u6cd5\u83b7\u53d6\u5b57\u6bb5\u957f\u5ea6\uff1a<\/p>\n<p><strong>1. \u4f7f\u7528 SELECT \u67e5\u8be2<\/strong><\/p>\n<pre>SELECT data_length FROM user_tab_columns\nWHERE table_name = 'table_name' AND column_name = 'column_name';<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>table_name \u662f\u60a8\u8981\u83b7\u53d6\u5b57\u6bb5\u957f\u5ea6\u7684\u8868\u7684\u540d\u79f0\u3002<\/li>\n<li>column_name \u662f\u60a8\u8981\u83b7\u53d6\u957f\u5ea6\u7684\u5b57\u6bb5\u7684\u540d\u79f0\u3002<\/li>\n<\/ul>\n<p><strong>2. \u4f7f\u7528 DESCRIBE \u547d\u4ee4<\/strong><\/p>\n<pre>DESCRIBE table_name;<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u8fd9\u5c06\u663e\u793a\u8868\u4e2d\u6240\u6709\u5b57\u6bb5\u7684\u4fe1\u606f\uff0c\u5305\u62ec\u5b57\u6bb5\u957f\u5ea6\u3002<\/p>\n<p><strong>3. \u4f7f\u7528 DBMS_METADATA \u5305<\/strong><\/p>\n<pre>SELECT length(column_name)\nFROM user_tab_columns\nWHERE table_name = 'table_name' AND column_name = 'column_name';<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u5176\u4e2d\uff1a<\/p>\n<ul>\n<li>length() \u51fd\u6570\u8fd4\u56de\u5b57\u6bb5\u7684\u957f\u5ea6\u3002<\/li>\n<\/ul>\n<p><strong>\u793a\u4f8b<\/strong><\/p>\n<p>\u4ee5\u4e0b\u793a\u4f8b\u83b7\u53d6\u8868 employees \u4e2d\u5b57\u6bb5 first_name \u7684\u957f\u5ea6\uff1a<\/p>\n<pre>SELECT data_length FROM user_tab_columns\nWHERE table_name = 'employees' AND column_name = 'first_name';<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u8fd9\u5c06\u8fd4\u56de\u5b57\u6bb5 first_name \u7684\u957f\u5ea6\uff0c\u901a\u5e38\u4e3a 30 \u4e2a\u5b57\u7b26\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662fOracle\u600e\u4e48\u83b7\u53d6\u5b57\u6bb5\u957f\u5ea6\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u65b9\u6cd5\u83b7\u53d6 oracle \u4e2d\u5b57\u6bb5\u957f\u5ea6\uff1a\u4f7f\u7528 select \u67e5\u8be2\uff1b\u4f7f\u7528 describe \u547d\u4ee4\uff1b\u4f7f\u7528 dbms_metadata \u5305\u3002 \u5982\u4f55\u83b7\u53d6 Oracle \u4e2d\u5b57\u6bb5\u7684\u957f\u5ea6 \u5728 Oracle \u6570\u636e\u5e93\u4e2d\uff0c\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u65b9\u6cd5\u83b7\u53d6\u5b57\u6bb5\u957f\u5ea6\uff1a 1. \u4f7f\u7528 SELECT \u67e5\u8be2 SELECT data_length FROM user_tab_columns WHERE table_name = &#8216;table_name&#8217; AND column_name = &#8216;column_name&#8217;; \u767b\u5f55\u540e\u590d\u5236 \u5176\u4e2d\uff1a table_name \u662f\u60a8\u8981\u83b7\u53d6\u5b57\u6bb5\u957f\u5ea6\u7684\u8868\u7684\u540d\u79f0\u3002 column_name \u662f\u60a8\u8981\u83b7\u53d6\u957f\u5ea6\u7684\u5b57\u6bb5\u7684\u540d\u79f0\u3002 2. \u4f7f\u7528 DESCRIBE \u547d\u4ee4 DESCRIBE table_name; \u767b\u5f55\u540e\u590d\u5236 \u8fd9\u5c06\u663e\u793a\u8868\u4e2d\u6240\u6709\u5b57\u6bb5\u7684\u4fe1\u606f\uff0c\u5305\u62ec\u5b57\u6bb5\u957f\u5ea6\u3002 3. \u4f7f\u7528 DBMS_METADATA \u5305 SELECT length(column_name) FROM user_tab_columns WHERE table_name [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-5751","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5751","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=5751"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5751\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=5751"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=5751"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=5751"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}