{"id":187634,"date":"2024-11-11T15:54:18","date_gmt":"2024-11-11T07:54:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/187634\/"},"modified":"2024-11-11T15:54:19","modified_gmt":"2024-11-11T07:54:19","slug":"%e6%95%b8%e6%93%9a%e5%ba%ab%e7%b4%84%e6%9d%9f%e8%a8%ad%e7%bd%ae%e6%8a%80%e5%b7%a7%e8%a9%b3%e8%a7%a3-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%b4%84%e6%9d%9f%e6%80%8e%e9%ba%bc%e8%a8%ad%e7%bd%ae","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/187634\/","title":{"rendered":"\u6578\u64da\u5eab\u7d04\u675f\u8a2d\u7f6e\u6280\u5de7\u8a73\u89e3 (\u6578\u64da\u5eab\u4e2d\u7d04\u675f\u600e\u9ebc\u8a2d\u7f6e)"},"content":{"rendered":"<h1 id=\"%e6%95%b8%e6%93%9a%e5%ba%ab%e7%b4%84%e6%9d%9f%e8%a8%ad%e7%bd%ae%e6%8a%80%e5%b7%a7%e8%a9%b3%e8%a7%a3-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%b4%84%e6%9d%9f%e6%80%8e%e9%ba%bc%e8%a8%ad%e7%bd%ae-hbQcDEqkbD\">\u6578\u64da\u5eab\u7d04\u675f\u8a2d\u7f6e\u6280\u5de7\u8a73\u89e3 (\u6578\u64da\u5eab\u4e2d\u7d04\u675f\u600e\u9ebc\u8a2d\u7f6e)<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u8a2d\u8a08\u4e2d\uff0c\u7d04\u675f\uff08Constraints\uff09\u662f\u78ba\u4fdd\u6578\u64da\u5b8c\u6574\u6027\u548c\u4e00\u81f4\u6027\u7684\u91cd\u8981\u5de5\u5177\u3002\u7d04\u675f\u53ef\u4ee5\u9650\u5236\u6578\u64da\u7684\u8f38\u5165\uff0c\u9632\u6b62\u4e0d\u6b63\u78ba\u6216\u4e0d\u5408\u898f\u7684\u6578\u64da\u9032\u5165\u6578\u64da\u5eab\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u6578\u64da\u5eab\u4e2d\u7d04\u675f\u7684\u985e\u578b\u53ca\u5176\u8a2d\u7f6e\u6280\u5de7\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u66f4\u597d\u5730\u7ba1\u7406\u6578\u64da\u3002<\/p>\n<h2 id=\"%e7%b4%84%e6%9d%9f%e7%9a%84%e9%a1%9e%e5%9e%8b-hbQcDEqkbD\">\u7d04\u675f\u7684\u985e\u578b<\/h2>\n<p>\u6578\u64da\u5eab\u4e2d\u7684\u7d04\u675f\u4e3b\u8981\u5206\u70ba\u4ee5\u4e0b\u5e7e\u7a2e\u985e\u578b\uff1a<\/p>\n<ul>\n<li><strong>\u4e3b\u9375\u7d04\u675f\uff08Primary Key Constraint\uff09<\/strong>: \u78ba\u4fdd\u6bcf\u4e00\u884c\u6578\u64da\u7684\u552f\u4e00\u6027\uff0c\u4e26\u4e14\u4e0d\u5141\u8a31\u7a7a\u503c\u3002<\/li>\n<li><strong>\u5916\u9375\u7d04\u675f\uff08Foreign Key Constraint\uff09<\/strong>: \u7528\u65bc\u5efa\u7acb\u5169\u500b\u8868\u4e4b\u9593\u7684\u95dc\u806f\uff0c\u78ba\u4fdd\u5f15\u7528\u7684\u6578\u64da\u5728\u4e3b\u8868\u4e2d\u5b58\u5728\u3002<\/li>\n<li><strong>\u552f\u4e00\u7d04\u675f\uff08Unique Constraint\uff09<\/strong>: \u78ba\u4fdd\u67d0\u4e00\u5217\u7684\u6578\u64da\u5728\u6574\u500b\u8868\u4e2d\u662f\u552f\u4e00\u7684\uff0c\u4f46\u5141\u8a31\u7a7a\u503c\u3002<\/li>\n<li><strong>\u6aa2\u67e5\u7d04\u675f\uff08Check Constraint\uff09<\/strong>: \u7528\u65bc\u9650\u5236\u67d0\u4e00\u5217\u7684\u6578\u64da\u7bc4\u570d\u6216\u683c\u5f0f\u3002<\/li>\n<li><strong>\u9ed8\u8a8d\u7d04\u675f\uff08Default Constraint\uff09<\/strong>: \u7576\u63d2\u5165\u6578\u64da\u6642\uff0c\u5982\u679c\u672a\u63d0\u4f9b\u67d0\u5217\u7684\u503c\uff0c\u5247\u4f7f\u7528\u9810\u8a2d\u503c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e8%a8%ad%e7%bd%ae%e7%b4%84%e6%9d%9f%e7%9a%84%e6%8a%80%e5%b7%a7-hbQcDEqkbD\">\u8a2d\u7f6e\u7d04\u675f\u7684\u6280\u5de7<\/h2>\n<h3 id=\"1-%e4%b8%bb%e9%8d%b5%e7%b4%84%e6%9d%9f%e7%9a%84%e8%a8%ad%e7%bd%ae-hbQcDEqkbD\">1. \u4e3b\u9375\u7d04\u675f\u7684\u8a2d\u7f6e<\/h3>\n<p>\u4e3b\u9375\u7d04\u675f\u901a\u5e38\u5728\u5275\u5efa\u8868\u6642\u8a2d\u7f6e\uff0c\u78ba\u4fdd\u6bcf\u4e00\u884c\u6578\u64da\u7684\u552f\u4e00\u6027\u3002\u4ee5\u4e0b\u662f\u8a2d\u7f6e\u4e3b\u9375\u7d04\u675f\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>CREATE TABLE Users (\n    UserID INT NOT NULL,\n    UserName VARCHAR(100) NOT NULL,\n    PRIMARY KEY (UserID)\n);<\/code><\/pre>\n<h3 id=\"2-%e5%a4%96%e9%8d%b5%e7%b4%84%e6%9d%9f%e7%9a%84%e8%a8%ad%e7%bd%ae-hbQcDEqkbD\">2. \u5916\u9375\u7d04\u675f\u7684\u8a2d\u7f6e<\/h3>\n<p>\u5916\u9375\u7d04\u675f\u7528\u65bc\u7dad\u8b77\u6578\u64da\u7684\u53c3\u7167\u5b8c\u6574\u6027\u3002\u8a2d\u7f6e\u5916\u9375\u7d04\u675f\u6642\uff0c\u9700\u8981\u6307\u5b9a\u4e3b\u8868\u548c\u5f9e\u8868\u7684\u95dc\u806f\u3002\u4ee5\u4e0b\u662f\u8a2d\u7f6e\u5916\u9375\u7d04\u675f\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>CREATE TABLE Orders (\n    OrderID INT NOT NULL,\n    UserID INT,\n    PRIMARY KEY (OrderID),\n    FOREIGN KEY (UserID) REFERENCES Users(UserID)\n);<\/code><\/pre>\n<h3 id=\"3-%e5%94%af%e4%b8%80%e7%b4%84%e6%9d%9f%e7%9a%84%e8%a8%ad%e7%bd%ae-hbQcDEqkbD\">3. \u552f\u4e00\u7d04\u675f\u7684\u8a2d\u7f6e<\/h3>\n<p>\u552f\u4e00\u7d04\u675f\u53ef\u4ee5\u5728\u8868\u5275\u5efa\u6642\u6216\u5f8c\u7e8c\u4fee\u6539\u6642\u8a2d\u7f6e\u3002\u4ee5\u4e0b\u662f\u8a2d\u7f6e\u552f\u4e00\u7d04\u675f\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>ALTER TABLE Users\nADD CONSTRAINT UniqueUserName UNIQUE (UserName);<\/code><\/pre>\n<h3 id=\"4-%e6%aa%a2%e6%9f%a5%e7%b4%84%e6%9d%9f%e7%9a%84%e8%a8%ad%e7%bd%ae-hbQcDEqkbD\">4. \u6aa2\u67e5\u7d04\u675f\u7684\u8a2d\u7f6e<\/h3>\n<p>\u6aa2\u67e5\u7d04\u675f\u7528\u65bc\u9650\u5236\u5217\u7684\u6578\u64da\u7bc4\u570d\u3002\u4ee5\u4e0b\u662f\u8a2d\u7f6e\u6aa2\u67e5\u7d04\u675f\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>CREATE TABLE Products (\n    ProductID INT NOT NULL,\n    Price DECIMAL(10, 2),\n    CHECK (Price &gt;= 0)\n);<\/code><\/pre>\n<h3 id=\"5-%e9%bb%98%e8%aa%8d%e7%b4%84%e6%9d%9f%e7%9a%84%e8%a8%ad%e7%bd%ae-hbQcDEqkbD\">5. \u9ed8\u8a8d\u7d04\u675f\u7684\u8a2d\u7f6e<\/h3>\n<p>\u9ed8\u8a8d\u7d04\u675f\u53ef\u4ee5\u5728\u5275\u5efa\u8868\u6642\u8a2d\u7f6e\uff0c\u6216\u5728\u8868\u5275\u5efa\u5f8c\u6dfb\u52a0\u3002\u4ee5\u4e0b\u662f\u8a2d\u7f6e\u9ed8\u8a8d\u7d04\u675f\u7684\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>ALTER TABLE Products\nADD CONSTRAINT DefaultStock DEFAULT 0 FOR Stock;<\/code><\/pre>\n<h2 id=\"%e7%b8%bd%e7%b5%90-hbQcDEqkbD\">\u7e3d\u7d50<\/h2>\n<p>\u6578\u64da\u5eab\u7d04\u675f\u662f\u78ba\u4fdd\u6578\u64da\u5b8c\u6574\u6027\u548c\u4e00\u81f4\u6027\u7684\u95dc\u9375\u5de5\u5177\u3002\u901a\u904e\u5408\u7406\u8a2d\u7f6e\u4e3b\u9375\u3001\u5916\u9375\u3001\u552f\u4e00\u3001\u6aa2\u67e5\u548c\u9ed8\u8a8d\u7d04\u675f\uff0c\u53ef\u4ee5\u6709\u6548\u5730\u7ba1\u7406\u6578\u64da\uff0c\u9632\u6b62\u4e0d\u6b63\u78ba\u7684\u6578\u64da\u9032\u5165\u7cfb\u7d71\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u7ba1\u7406\u7684\u4f01\u696d\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\u81f3\u95dc\u91cd\u8981\u3002\u82e5\u60a8\u5c0d\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u6216\u5176\u4ed6\u6578\u64da\u5eab\u7ba1\u7406\u89e3\u6c7a\u65b9\u6848\u6709\u8208\u8da3\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8cc7\u8a0a\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22\u6578\u64da\u5eab\u7d04\u675f\u8a2d\u7f6e\u6280\u5de7\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u914d\u7f6e\u7d04\u675f\u4ee5\u78ba\u4fdd\u6578\u64da\u5b8c\u6574\u6027\u548c\u4e00\u81f4\u6027\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-187634","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187634","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=187634"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187634\/revisions"}],"predecessor-version":[{"id":187635,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187634\/revisions\/187635"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=187634"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=187634"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=187634"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}