{"id":1337,"date":"2015-12-06T20:28:48","date_gmt":"2015-12-06T12:28:48","guid":{"rendered":"http:\/\/coderbee.net\/?p=1337"},"modified":"2015-12-07T21:14:16","modified_gmt":"2015-12-07T13:14:16","slug":"%e3%80%8a%e9%ab%98%e6%80%a7%e8%83%bd-mysql%e3%80%8b-%e7%ac%ac%e5%9b%9b%e7%ab%a0-schema-%e4%b8%8e%e6%95%b0%e6%8d%ae%e7%b1%bb%e5%9e%8b%e4%bc%98%e5%8c%96","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/db\/20151206\/1337","title":{"rendered":"\u300a\u9ad8\u6027\u80fd MySQL\u300b &#8212; \u7b2c\u56db\u7ae0 Schema \u4e0e\u6570\u636e\u7c7b\u578b\u4f18\u5316"},"content":{"rendered":"<h2>\u9009\u62e9\u4f18\u5316\u7684\u6570\u636e\u7c7b\u578b<\/h2>\n<p>\u9009\u62e9\u6570\u636e\u7c7b\u578b\u7684\u4e00\u822c\u539f\u5219\uff1a<\/p>\n<ul>\n<li>\n<p>\u66f4\u5c0f\u7684\u901a\u5e38\u66f4\u597d\uff1a\u5c3d\u91cf\u4f7f\u7528\u53ef\u4ee5\u6b63\u786e\u5b58\u50a8\u6570\u636e\u7684\u6700\u5c0f\u6570\u636e\u7c7b\u578b\u3002<\/p>\n<\/li>\n<li>\n<p>\u7b80\u5355\u5c31\u597d\uff1a\u7b80\u5355\u6570\u636e\u7c7b\u578b\u7684\u64cd\u4f5c\u901a\u5e38\u9700\u8981\u66f4\u5c11\u7684 CPU \u5468\u671f\u3002\u4f8b\u5982\u6574\u578b\u6bd4\u5b57\u7b26\u64cd\u4f5c\u4ee3\u4ef7\u66f4\u4f4e\uff0c\u4ee5\u4e3a\u5b57\u7b26\u96c6\u548c\u6821\u5bf9\u89c4\u5219\uff08\u6392\u5e8f\u89c4\u5219\uff09\u4f7f\u5b57\u7b26\u6bd4\u8f83\u6bd4\u6574\u578b\u66f4\u590d\u6742\u3002\u4e3e\u4f8b\uff0c\u5e94\u8be5\u4f7f\u7528 MySQL \u5185\u5efa\u7684\u7c7b\u578b\uff08date, time, datetime\uff09 \u800c\u4e0d\u662f\u5b57\u7b26\u4e32\u6765\u5b58\u50a8\u65e5\u671f\u548c\u65f6\u95f4\uff0c\u5e94\u8be5\u4f7f\u7528\u6574\u578b\u6765\u5b58\u50a8 IP \u5730\u5740\u3002<\/p>\n<\/li>\n<li>\n<p>\u5c3d\u91cf\u907f\u514d NULL\uff1a\u5982\u679c\u67e5\u8be2\u4e2d\u5305\u542b\u53ef\u4e3a NULL \u7684\u5217\uff0c\u5bf9 MySQL \u6765\u8bf4\u66f4\u96be\u4f18\u5316\uff0c\u56e0\u4e3a\u53ef\u4e3a NULL \u7684\u5217\u4f7f\u5f97\u7d22\u5f15\u3001\u7d22\u5f15\u7edf\u8ba1\u548c\u503c\u6bd4\u8f83\u90fd\u66f4\u590d\u6742\u3002\u53ef\u4e3a NULL \u7684\u5217\u4f1a\u4f7f\u7528\u66f4\u591a\u7684\u5b58\u50a8\u7a7a\u95f4\uff0c\u5728 MySQL \u91cc\u4e5f\u9700\u8981\u7279\u6b8a\u5904\u7406\u3002\u5f53\u53ef\u4e3a NULL \u7684\u5217\u88ab\u7d22\u5f15\u65f6\uff0c\u6bcf\u4e2a\u7d22\u5f15\u8bb0\u5f55\u9700\u8981\u4e00\u4e2a\u989d\u5916\u7684\u5b57\u8282\uff0c\u5728 MyISAM \u91cc\u751a\u81f3\u8fd8\u53ef\u80fd\u5bfc\u81f4\u56fa\u5b9a\u5927\u5c0f\u7684\u7d22\u5f15\u53d8\u6210\u53ef\u53d8\u5927\u5c0f\u7684\u7d22\u5f15\u3002\u4f8b\u5916\uff0c\u5bf9\u4e8e\u7a00\u758f\u6570\u636e\uff08\u5f88\u591a\u5217\u7684\u503c\u4e3a NULL\uff09\uff0cInnoDB \u4f7f\u7528\u5355\u72ec\u7684\u4f4d\uff08bit\uff09\u5b58\u50a8 NULL \u503c\uff0c\u6709\u5f88\u597d\u7684\u7a7a\u95f4\u6548\u7387\u3002<\/p>\n<\/li>\n<\/ul>\n<p>\u5728\u4e3a\u5217\u9009\u62e9\u6570\u636e\u7c7b\u578b\u65f6\uff0c\u7b2c\u4e00\u6b65\u9700\u8981\u786e\u5b9a\u5408\u9002\u7684\u5927\u7c7b\u578b\uff1a\u6570\u5b57\u3001\u5b57\u7b26\u4e32\u3001\u65f6\u95f4\u7b49\u3002\u4e0b\u4e00\u6b65\u662f\u9009\u62e9\u5177\u4f53\u7c7b\u578b\u3002<\/p>\n<p><!--more--><\/p>\n<h3>\u6574\u6570\u7c7b\u578b<\/h3>\n<p>TINYINT\uff088\uff09\uff0c SMALLINT\uff0816\uff09\uff0c MEDIUMINT\uff0824\uff09\uff0c INT\uff0832\uff09\uff0cBIGINT\uff0864\uff09\uff0c\u540e\u9762\u7684\u6570\u5b57\u8868\u793a\u5b58\u50a8\u7a7a\u95f4\u7684\u4f4d\u6570 N\uff0c\u53ef\u4ee5\u5b58\u50a8\u7684\u503c\u7684\u8303\u56f4\u4ece <code>-2^(N-1)<\/code> \u5230 <code>2^(N-1) - 1<\/code>\u3002<\/p>\n<p>\u6574\u6570\u7c7b\u578b\u8fd8\u6709\u53ef\u9009\u7684 UNSIGNED \u5c5e\u6027\uff0c\u8868\u793a\u4e0d\u5141\u8bb8\u8d1f\u503c\uff0c\u53ef\u4ee5\u4f7f\u6574\u6570\u7684\u4e0a\u9650\u63d0\u9ad8\u4e00\u500d\u3002\u6709\u7b26\u53f7\u548c\u65e0\u7b26\u53f7\u7c7b\u578b\u4f7f\u7528\u76f8\u540c\u7684\u5b58\u50a8\u7a7a\u95f4\uff0c\u5e76\u5177\u6709\u76f8\u540c\u7684\u6027\u80fd\u3002<\/p>\n<p>\u6570\u636e\u7c7b\u578b\u51b3\u5b9a\u4e86 MySQL \u600e\u4e48\u5728\u5185\u5b58\u548c\u78c1\u76d8\u4e2d\u4fdd\u5b58\u6570\u636e\uff0c\u4f46\u6574\u6570\u8ba1\u7b97\u4e00\u822c\u4f7f\u7528 64 \u4f4d\u7684 BIGINT \u6574\u6570\uff0c\u5373\u4f7f\u5728 32 \u4f4d\u73af\u5883\u4e5f\u662f\u3002\uff08\u4e00\u4e9b\u805a\u5408\u51fd\u6570\u662f\u4f8b\u5916\uff0c\u4f7f\u7528 DECIMAL\/DOUBLE \u8fdb\u884c\u8ba1\u7b97\u3002\uff09<\/p>\n<p>MySQL \u53ef\u4ee5\u4e3a\u6574\u6570\u7c7b\u578b\u6307\u5b9a\u5bbd\u5ea6\uff0c\u5b83\u53ea\u662f\u89c4\u5b9a\u4e86\u4e00\u4e9b\u4ea4\u4e92\u5de5\u5177\u7528\u6765\u663e\u793a\u5b57\u7b26\u7684\u4e2a\u6570\u3002\u5bf9\u4e8e\u5b58\u50a8\u548c\u8ba1\u7b97\uff0c<code>INT(1)<\/code> \u548c <code>INT(20)<\/code> \u662f\u76f8\u540c\u7684\u3002<\/p>\n<h3>\u5b9e\u6570\u7c7b\u578b<\/h3>\n<p>\u5b9e\u6570\u662f\u5e26\u6709\u5c0f\u6570\u90e8\u5206\u7684\u6570\u5b57\u3002<\/p>\n<p>DECIMAL \u7c7b\u578b\u7528\u4e8e\u5b58\u50a8\u7cbe\u786e\u7684\u5c0f\u6570\uff0c\u53ef\u4ee5\u6307\u5b9a\u5c0f\u6570\u70b9\u524d\u540e\u6240\u5141\u8bb8\u7684\u6700\u5927\u4f4d\u6570\u3002<\/p>\n<h3>\u5b57\u7b26\u4e32\u7c7b\u578b<\/h3>\n<p>\u5b58\u50a8\u5f15\u64ce\u5b58\u50a8 varchar \u548c char \u503c\u7684\u65b9\u5f0f\u5728\u5185\u5b58\u4e2d\u548c\u5728\u78c1\u76d8\u4e0a\u53ef\u80fd\u4e0d\u4e00\u6837\uff0c\u6240\u4ee5 MySQL \u670d\u52a1\u5668\u4ece\u5b58\u50a8\u5f15\u64ce\u8bfb\u51fa\u7684\u503c\u53ef\u80fd\u9700\u8981\u8f6c\u6362\u4e3a\u53e6\u4e00\u79cd\u5b58\u50a8\u683c\u5f0f\u3002<\/p>\n<ul>\n<li>\n<p>varchar\uff1a\u4ec5\u4f7f\u7528\u5fc5\u8981\u7684\u7a7a\u95f4\uff0c\u4f46\u9700\u8981\u989d\u5916\u7684 1 \u6216 2 \u4e2a\u5b57\u8282\u6765\u8bb0\u5f55\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\u3002\u9002\u5408\u4f7f\u7528 varchar \u7684\u573a\u666f\uff1a\u5b57\u7b26\u4e32\u5217\u7684\u6700\u5927\u957f\u5ea6\u6bd4\u5e73\u5747\u957f\u5ea6\u5927\u5f88\u591a\uff1b\u5217\u7684\u66f4\u65b0\u5f88\u5c11\uff0c\u6240\u4ee5\u788e\u7247\u4e0d\u662f\u95ee\u9898\uff1b\u4f7f\u7528\u4e86\u50cf UTF8 \u8fd9\u6837\u590d\u6742\u7684\u5b57\u7b26\u96c6\uff0c\u6bcf\u4e2a\u5b57\u7b26\u90fd\u4f7f\u7528\u4e0d\u540c\u7684\u5b57\u8282\u8fdb\u884c\u5b58\u50a8\u3002<\/p>\n<\/li>\n<li>\n<p>char\uff1a\u5b9a\u957f\u7684\uff0c\u4e0d\u5bb9\u6613\u4ea7\u751f\u788e\u7247\u3002\u5b58\u50a8 char \u503c\u65f6\uff0cMySQL \u4f1a\u5220\u9664\u6240\u6709\u7684\u672b\u5c3e\u7a7a\u683c\uff0c\u8fdb\u884c\u6bd4\u8f83\u65f6\u4f1a\u7528\u7a7a\u683c\u8fdb\u884c\u586b\u5145\u3002<\/p>\n<\/li>\n<\/ul>\n<h4>\u679a\u4e3e\uff08enum\uff09<\/h4>\n<p>\u4f7f\u7528\u679a\u4e3e\uff08enum\uff09\u4ee3\u66ff\u5b57\u7b26\u4e32\u7c7b\u578b\uff1aMySQL \u5728\u5185\u90e8\u4f1a\u5c06\u6bcf\u4e2a\u503c\u5728\u5217\u8868\u4e2d\u7684\u4f4d\u7f6e\u4fdd\u5b58\u4e3a\u6574\u6570\uff0c\u5e76\u4e14\u5728\u8868\u7684 <code>.frm<\/code> \u6587\u4ef6\u4e2d\u4fdd\u5b58 \u201d\u6570\u5b57 &#8211; \u5b57\u7b26\u4e32\u201c\u6620\u5c04\u5173\u7cfb\u7684\u201d\u67e5\u627e\u8868\u201c\u3002\u5b58\u50a8\u7a7a\u95f4\u4e00\u822c\u53ea\u9700\u8981\u4e00\u4e2a\u6216\u4e24\u4e2a\u5b57\u8282\u3002<\/p>\n<pre><code class=\"sql\">create table enum_test(\n     e enum('fish',  'apple',  'dog) not null\n);\n\ninsert into enum_test(e) values('fish'), ('dog'), ('apple');\n<\/code><\/pre>\n<p>\u679a\u4e3e\u7684\u95ee\u9898\uff1a<\/p>\n<blockquote>\n<ol>\n<li>\u679a\u4e3e\u5b57\u6bb5\u662f\u6309\u7167\u5185\u90e8\u5b58\u50a8\u7684\u6574\u6570\u800c\u4e0d\u662f\u5b9a\u4e49\u7684\u5b57\u7b26\u4e32\u8fdb\u884c\u6392\u5e8f\u7684\u3002\u7ed5\u8fc7\u9650\u5236\u7684\u65b9\u5f0f\u662f\u6309\u7167\u9700\u8981\u7684\u987a\u5e8f\u6765\u5b9a\u4e49\u679a\u4e3e\uff1b\u6216\u8005\u5728\u67e5\u8be2\u4e2d\u4f7f\u7528 <code>field<\/code> \u51fd\u6570\u663e\u5f0f\u5730\u6307\u5b9a\u6392\u5e8f\u987a\u5e8f\uff0c\u4f46\u8fd9\u4f1a\u5bfc\u81f4 MySQL \u65e0\u6cd5\u5229\u7528\u7d22\u5f15\u6d88\u9664\u6392\u5e8f\u3002<\/li>\n<li>\u5b57\u7b26\u4e32\u5217\u8868\u662f\u56fa\u5b9a\u7684\uff0c\u6dfb\u52a0\u6216\u5220\u9664\u5b57\u7b26\u4e32\u5fc5\u987b\u4f7f\u7528 <code>alter table<\/code>\uff0c\u5982\u679c\u80fd\u63a5\u53d7\u53ea\u5728\u5217\u8868\u7684\u672b\u5c3e\u6dfb\u52a0\u5143\u7d20\uff0c\u90a3\u4e48 MySQL \u5c31\u53ef\u4ee5\u4e0d\u7528\u91cd\u5efa\u6574\u4e2a\u8868\u6765\u5b8c\u6210\u4fee\u6539\u3002<br \/>\n  3   MySQL \u628a\u6bcf\u4e2a\u679a\u4e3e\u503c\u4fdd\u5b58\u4e3a\u6574\u6570\uff0c\u5e76\u4e14\u5fc5\u987b\u8fdb\u884c\u67e5\u627e\u624d\u80fd\u8f6c\u6362\u4e3a\u5b57\u7b26\u4e32\uff0c\u8fd9\u4f1a\u5e26\u6765\u4e00\u5b9a\u7684\u5f00\u9500\u3002<\/li>\n<\/ol>\n<\/blockquote>\n<h3>\u65e5\u671f\u548c\u65f6\u95f4\u7c7b\u578b<\/h3>\n<p>MySQL \u80fd\u5b58\u50a8\u7684\u6700\u5c0f\u65f6\u95f4\u7c92\u5ea6\u4e3a\u79d2\u3002<\/p>\n<ul>\n<li>\n<p>datetime\uff1a\u8fd9\u4e2a\u7c7b\u578b\u80fd\u4fdd\u5b58\u5927\u8303\u56f4\u7684\u503c\uff0c\u4ece 1001 \u5e74\u5230 9999 \u5e74\uff0c\u7cbe\u5ea6\u4e3a\u79d2\u3002\u5b83\u628a\u65e5\u671f\u548c\u65f6\u95f4\u5c01\u88c5\u5230\u683c\u5f0f\u4e3a YYYYMMDDHHMMSS \u7684\u6574\u6570\u4e2d\uff0c\u4e0e\u65f6\u533a\u65e0\u5173\u3002\u4f7f\u7528 8 \u4e2a\u5b57\u8282\u7684\u5b58\u50a8\u7a7a\u95f4\u3002<\/p>\n<\/li>\n<li>\n<p>timestamp\uff1a\u4fdd\u5b58\u4e86\u4ece 1970 \u5e74 1 \u6708 1 \u65e5\u5348\u591c\u4ee5\u6765\u7684\u79d2\u6570\uff0c\u548c UNIX \u65f6\u95f4\u6233\u76f8\u540c\u3002\u53ea\u4f7f\u7528 4 \u4e2a\u5b57\u8282\u7684\u5b58\u50a8\u7a7a\u95f4\uff0c\u53ea\u80fd\u8868\u793a\u4ece 1970 \u5e74\u5230 2038 \u5e74\u3002<\/p>\n<\/li>\n<\/ul>\n<h3>\u9009\u62e9\u6807\u8bc6\u7b26\uff08identifier\uff09<\/h3>\n<p>\u4e3a\u6807\u8bc6\u5217\uff08identifier column\uff09\u9009\u62e9\u5408\u9002\u7684\u6570\u636e\u7c7b\u578b\u975e\u5e38\u91cd\u8981\uff0c\u4e0b\u9762\u662f\u4e00\u4e9b\u5c0f\u6280\u5de7\uff1a<\/p>\n<ul>\n<li>\u6574\u6570\u7c7b\u578b\uff1a\u6574\u6570\u901a\u5e38\u662f\u6807\u8bc6\u5217\u6700\u597d\u7684\u9009\u62e9\uff0c\u56e0\u4e3a\u5b83\u4eec\u5f88\u5feb\u5e76\u4e14\u53ef\u4ee5\u4f7f\u7528 AUTO_INCREMENT\u3002<\/li>\n<li>ENUM \u548c SET \u7c7b\u578b\uff1a\u901a\u5e38\u4e0d\u662f\u6807\u8bc6\u5217\u7684\u597d\u9009\u62e9\u3002MySQL \u5728\u5185\u90e8\u4f7f\u7528\u6574\u6570\u5b58\u50a8 ENUM \u548c SET \u7c7b\u578b\uff0c\u7136\u540e\u5728\u505a\u6bd4\u8f83\u65f6\u8f6c\u6362\u4e3a\u5b57\u7b26\u4e32\u3002<\/li>\n<li>\u5b57\u7b26\u4e32\u7c7b\u578b\uff1a\u5c3d\u91cf\u907f\u514d\uff0c\u8017\u7a7a\u95f4\uff0c\u6bd4\u6570\u5b57\u7c7b\u578b\u6162\u3002\u5bf9\u4e8e\u5b8c\u5168 &#8220;\u968f\u673a&#8221; \u7684\u5b57\u7b26\u4e32\uff0c\u4f1a\u5206\u5e03\u5728\u5f88\u5927\u7684\u7a7a\u95f4\u5185\uff0c\u8fd9\u4f1a\u5bfc\u81f4 insert \u4ee5\u53ca\u4e00\u4e9b select \u8bed\u53e5\u53d8\u5f97\u5f88\u6162\uff1a<br \/>\n>    *    \u56e0\u4e3a\u63d2\u5165\u503c\u4f1a\u968f\u673a\u5730\u5199\u5230\u7d22\u5f15\u7684\u4e0d\u540c\u4f4d\u7f6e\uff0c\u4f7f\u5f97 insert \u8bed\u53e5\u66f4\u6162\u3002\u8fd9\u4f1a\u5bfc\u81f4 \u9875\u5206\u88c2\u3001\u78c1\u76d8\u968f\u673a\u8bbf\u95ee\uff0c\u4ee5\u53ca\u5bf9\u4e8e\u805a\u65cf\u5b58\u50a8\u5f15\u64ce\u4ea7\u751f\u805a\u65cf\u7d22\u5f15\u788e\u7247\u3002<br \/>\n>    *    select \u8bed\u53e5\u4f1a\u53d8\u5f97\u66f4\u6162\uff0c\u56e0\u4e3a\u903b\u8f91\u4e0a\u76f8\u90bb\u7684\u884c\u4f1a\u5206\u5e03\u5728\u78c1\u76d8\u548c\u5185\u5b58\u7684\u4e0d\u540c\u5730\u65b9\u3002<br \/>\n>    *    \u968f\u673a\u503c\u4f1a\u5bfc\u81f4\u7f13\u5b58\u5bf9\u4e8e\u6240\u6709\u7c7b\u578b\u7684\u67e5\u8be2\u8bed\u53e5\u6548\u679c\u90fd\u5f88\u5dee\uff0c\u56e0\u4e3a\u4f1a\u4f7f\u5f97\u7f13\u5b58\u8d56\u4ee5\u5de5\u4f5c\u7684\u8bbf\u95ee\u5c40\u90e8\u6027\u539f\u7406\u5931\u6548\u3002<br \/>\n>    *    \u53e6\u4e00\u65b9\u9762\uff0c\u5bf9\u4e00\u4e9b\u6709\u5f88\u591a\u5199\u7684\u7279\u522b\u5927\u7684\u8868\uff0c\u8fd9\u79cd\u4f2a\u968f\u673a\u503c\u5b9e\u9645\u4e0a\u53ef\u4ee5\u5e2e\u52a9\u6d88\u9664\u70ed\u70b9\u3002<\/li>\n<\/ul>\n<h2>MySQL schema \u8bbe\u8ba1\u4e2d\u7684\u9677\u9631<\/h2>\n<ul>\n<li>\u592a\u591a\u7684\u5217\uff1aMySQL \u7684\u5b58\u50a8\u5f15\u64ce API \u5de5\u4f5c\u65f6\u9700\u8981\u5728\u670d\u52a1\u5668\u5c42\u548c\u5b58\u50a8\u5f15\u64ce\u5c42\u4e4b\u95f4\u901a\u8fc7\u884c\u7f13\u51b2\u683c\u5f0f\u62f7\u8d1d\u6570\u636e\uff0c\u7136\u540e\u5728\u670d\u52a1\u5668\u5c42\u5c06\u7f13\u51b2\u5185\u5bb9\u89e3\u7801\u6210\u5404\u4e2a\u5217\u3002\u4ece\u884c\u7f13\u51b2\u4e2d\u5c06\u7f16\u7801\u8fc7\u7684\u5217\u8f6c\u6362\u6210\u884c\u6570\u636e\u7ed3\u6784\u7684\u64cd\u4f5c\u4ee3\u4ef7\u662f\u975e\u5e38\u9ad8\u7684\uff0c\u8f6c\u6362\u7684\u4ee3\u4ef7\u4f9d\u8d56\u4e8e\u5217\u7684\u6570\u91cf\u3002<\/li>\n<li>\u592a\u591a\u7684\u5173\u8054\uff1aMySQL \u9650\u5236\u4e86\u6bcf\u4e2a\u5173\u8054\u64cd\u4f5c\u6700\u591a\u53ea\u80fd\u6709 61 \u5f20\u8868\u3002<\/li>\n<li>\u5168\u80fd\u7684\u679a\u4e3e\uff1a<\/li>\n<li>\u53d8\u76f8\u7684\u679a\u4e3e\uff1a\u679a\u4e3e\u5217\u5141\u8bb8\u5728\u5217\u4e2d\u5b58\u50a8\u4e00\u7ec4\u5b9a\u4e49\u503c\u4e2d\u7684\u5355\u4e2a\u503c\uff0c\u96c6\u5408\u5217\u5219\u5141\u8bb8\u5728\u5217\u4e2d\u5b58\u50a8\u4e00\u7ec4\u5b9a\u4e49\u503c\u4e2d\u7684\u4e00\u4e2a\u591a\u591a\u4e2a\u503c\u3002<\/li>\n<li>\u975e\u6b64\u53d1\u660e\u7684 NULL\uff1aMySQL \u4f1a\u5728\u7d22\u5f15\u4e2d\u5b58\u50a8 NULL \u503c\uff0c\u800c Oracle \u5219\u4e0d\u4f1a\u3002<\/li>\n<\/ul>\n<h2>\u8303\u5f0f\u548c\u53cd\u8303\u5f0f<\/h2>\n<p>\u8303\u5f0f\u5316\u7684\u597d\u5904\uff1a<\/p>\n<ul>\n<li>\u8303\u5f0f\u5316\u7684\u66f4\u65b0\u64cd\u4f5c\u901a\u5e38\u6bd4\u53cd\u8303\u5f0f\u5316\u8981\u5feb\uff1b<\/li>\n<li>\u5f53\u6570\u636e\u8f83\u597d\u5730\u8303\u5f0f\u5316\u65f6\uff0c\u5c31\u53ea\u6709\u5f88\u5c11\u6216\u8005\u6ca1\u6709\u91cd\u590d\u6570\u636e\uff0c\u6240\u4ee5\u53ea\u9700\u8981\u4fee\u6539\u66f4\u5c11\u7684\u6570\u636e\uff1b<\/li>\n<li>\u8303\u5f0f\u5316\u7684\u8868\u901a\u5e38\u66f4\u5c0f\uff0c\u53ef\u4ee5\u66f4\u597d\u5730\u653e\u5728\u5185\u5b58\u91cc\uff0c\u6240\u4ee5\u6267\u884c\u64cd\u4f5c\u4f1a\u66f4\u5feb\uff1b<\/li>\n<li>\u5f88\u5c11\u6709\u591a\u4f59\u7684\u6570\u636e\u610f\u5473\u7740\u68c0\u7d22\u5217\u8868\u6570\u636e\u65f6\u66f4\u5c11\u9700\u8981 <code>distinct<\/code> \u6216\u8005 <code>group by<\/code> \u8bed\u53e5\u3002<\/li>\n<\/ul>\n<p>\u8303\u5f0f\u5316\u8bbe\u8ba1\u7684\u7f3a\u70b9\u662f\u901a\u5e38\u9700\u8981\u5173\u8054\u3002<\/p>\n<p>\u53cd\u8303\u5f0f\u5316\u4f7f\u6570\u636e\u5b58\u653e\u5728\u5c3d\u53ef\u80fd\u5c11\u7684\u8868\u91cc\uff0c\u5f88\u597d\u5730\u907f\u514d\u5173\u8054\u3002<\/p>\n<p>\u6700\u5e38\u89c1\u7684\u53cd\u8303\u5f0f\u5316\u6570\u636e\u7684\u65b9\u6cd5\u662f\u590d\u5236\u6216\u8005\u7f13\u5b58\uff0c\u5728\u4e0d\u540c\u7684\u8868\u4e2d\u5b58\u50a8\u76f8\u540c\u7684\u7279\u5b9a\u5217\u3002<\/p>\n<h2>\u7f13\u5b58\u8868\u548c\u6c47\u603b\u8868<\/h2>\n<p><code>ON DUPLICATE KEY UPDATE<\/code> \u53ef\u4ee5\u5b9e\u73b0\u4e0d\u5b58\u5728\u5219\u63d2\u5165\u3001\u5b58\u5728\u5219\u66f4\u65b0\u7684\u903b\u8f91\uff1a<\/p>\n<pre><code class=\"sql\">insert into daily_hit_counter(day, slot, cnt)\nvalues (current_date, rand() * 100, 1)\non duplicate key update cnt = cnt + 1;\n<\/code><\/pre>\n<h2>\u52a0\u5feb alter table \u64cd\u4f5c\u7684\u901f\u5ea6<\/h2>\n<p>MySQL \u6267\u884c\u5927\u90e8\u5206\u4fee\u6539\u8868\u7ed3\u6784\u64cd\u4f5c\u7684\u65b9\u6cd5\u662f\u7528\u65b0\u7684\u7ed3\u6784\u521b\u5efa\u4e00\u4e2a\u7a7a\u8868\uff0c\u4ece\u65e7\u8868\u4e2d\u67e5\u51fa\u6240\u6709\u6570\u636e\u63d2\u5165\u65b0\u8868\uff0c\u7136\u540e\u5220\u9664\u65e7\u8868\u3002<\/p>\n<h3>\u5feb\u901f\u521b\u5efa MyISAM \u7d22\u5f15<\/h3>\n<p>\u4e3a\u4e86\u9ad8\u6548\u5730\u8f7d\u5165\u6570\u636e\uff0c\u5e38\u7528\u7684\u6280\u5de7\u662f\u5148\u7981\u7528\u7d22\u5f15\uff08<code>disable keys<\/code>\uff09\u3001\u8f7d\u5165\u6570\u636e\uff0c\u7136\u540e\u91cd\u65b0\u542f\u52a8\u7d22\u5f15\u3002\u4f46 <code>disable keys<\/code> \u53ea\u5bf9\u975e\u552f\u4e00\u7d22\u5f15\u6709\u6548\u3002<\/p>\n<p>MyISAM \u4e3a\u5728\u5185\u5b58\u4e2d\u6784\u9020\u552f\u4e00\u7d22\u5f15\uff0c\u5e76\u4e14\u4e3a\u8f7d\u5165\u7684\u6bcf\u4e00\u884c\u68c0\u67e5\u552f\u4e00\u6027\u3002<\/p>\n<hr\/>\n<p>\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u5fae\u4fe1\u516c\u4f17\u53f7: <strong>coderbee\u7b14\u8bb0<\/strong>\uff0c\u53ef\u4ee5\u66f4\u53ca\u65f6\u56de\u590d\u4f60\u7684\u8ba8\u8bba\u3002<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"258\" height=\"258\" src=\"https:\/\/coderbee.net\/wp-content\/uploads\/2019\/01\/coderbee-note.jpg\" class=\"alignnone size-full wp-image-1707\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u9009\u62e9\u4f18\u5316\u7684\u6570\u636e\u7c7b\u578b \u9009\u62e9\u6570\u636e\u7c7b\u578b\u7684\u4e00\u822c\u539f\u5219\uff1a \u66f4\u5c0f\u7684\u901a\u5e38\u66f4\u597d\uff1a\u5c3d\u91cf\u4f7f\u7528\u53ef\u4ee5\u6b63\u786e\u5b58 &hellip; <a href=\"https:\/\/coderbee.net\/index.php\/db\/20151206\/1337\">\u7ee7\u7eed\u9605\u8bfb <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[149,245,244],"_links":{"self":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1337"}],"collection":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/comments?post=1337"}],"version-history":[{"count":1,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1337\/revisions"}],"predecessor-version":[{"id":1338,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1337\/revisions\/1338"}],"wp:attachment":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/media?parent=1337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/categories?post=1337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/tags?post=1337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}