{"id":1774,"date":"2018-06-20T11:54:30","date_gmt":"2018-06-20T03:54:30","guid":{"rendered":"http:\/\/ufqi.com\/blog\/?p=1774"},"modified":"2018-06-21T11:45:36","modified_gmt":"2018-06-21T03:45:36","slug":"sql-optimize-unique-and-index","status":"publish","type":"post","link":"https:\/\/ufqi.com\/blog\/sql-optimize-unique-and-index\/","title":{"rendered":"SQL\u67e5\u8be2\u4f18\u5316: \u65e2\u6709Unique Index\u4e3a\u4f55\u8fd8\u8981\u53e6\u52a0Index?"},"content":{"rendered":"

\u5728\u4f7f\u7528 -GWA2<\/a> \u8fdb\u884cWebApp\u5f00\u53d1\u65f6\uff0c\u6211\u4eec\u521b\u5efa\u57fa\u4e8eMySQL\u7684\u76f8\u5173\u6570\u636e\u8868\u65f6\uff0c\u90fd\u4f1a\u6709\u610f\u8bc6\u5730\u5728\u6570\u636e\u8868\u7684\u5173\u952e\u5b57\u6bb5\u4e0a\u589e\u52a0\u7d22\u5f15\uff0c\u4ee5\u671f\u5f85\u67e5\u8be2\u65f6\u80fd\u591f\u8f83\u5feb\u5730\u8fd4\u56de\u7ed3\u679c\u96c6\u3002<\/p>\n

\u5728\u6211\u4eec\u73b0\u6709\u7684\u751f\u4ea7\u7ebf\u4e0a\u7684\u6570\u636e\u89c2\u6d4b\u4e2d\uff0c\u540c\u6837\u4e00\u5f20\u6570\u636e\u8868\uff0c\u901a\u5e38\u5f53\u6570\u636e\u8fbe\u523010M+\u65f6\uff0c\u5982\u679c\u67d0\u4e2a\u5f85\u68c0\u7d22\u5b57\u6bb5\uff08\u7528\u5728Where\u91cc\u4f5c\u4e3a\u67e5\u8be2\u5b57\u6bb5\uff09\u6ca1\u6709\u4f7f\u7528\u7d22\u5f15\uff0c\u4e00\u6b21\u67e5\u8be2\u5927\u7ea6\u9700\u8981\u8017\u65f650s+\uff0c\u5982\u679c\u589e\u52a0\u4e86\u76f8\u5e94\u7684\u7d22\u5f15\uff0c\u5219\u5355\u6b21\u67e5\u8be2\u5927\u7ea6\u8017\u65f65s\u5de6\u53f3\uff0c\u6027\u80fd\u63d0\u534710\u500d\u4ee5\u4e0a\u3002<\/p>\n

\u6240\u4ee5\uff0c\u7406\u8bba\u8054\u7cfb\u5b9e\u9645\uff0c\u6211\u4eec\u90fd\u5e94\u8be5\u5728\u76f8\u5173\u5f85\u68c0\u7d22\u7684\u5b57\u6bb5\u4e0a\u589e\u52a0\u7d22\u5f15\uff0c\u8fd9\u6b21\u8981\u63d0\u53ca\u548c\u6f84\u6e05\u7684\u662f\u589e\u52a0Unique Index\u8fd8\u662fIndex? \u53ea\u589e\u52a0Unique Index\uff0c\u8fd8\u662fIndex\u5373\u53ef\uff1f\u6216\u8005\u4e24\u79cdIndex\u90fd\u9700\u8981\uff1f \u5728\u68c0\u7d22\u65b9\u9762\uff0cUnique Index\u4fdd\u6301\u4e86\u6570\u636e\u7684\u552f\u4e00\u6027\uff0c\u5b9e\u9645\u517c\u6709Index\u7684\u529f\u80fd\uff0c\u5728\u88ab\u68c0\u7d22\u65f6\u63d0\u4f9b\u540c\u6837\u7684\u4f18\u5316\u6027\u80fd\u3002<\/p>\n

\u60c5\u51b5\u7a0d\u5fae\u590d\u6742\u4e00\u4e9b\u7684\u4f8b\u5b50\u662f\u8fd9\u6837\uff0c\u5f53\u4e00\u4e2aUnique Index\u589e\u52a0\u5230\u591a\u4e2a\u5b57\u6bb5\u7684\u7ec4\u5408\u4e0a\u65f6\uff0c\u5176Index\u7684\u4f5c\u7528\u5e76\u4e0d\u80fd\u60f3\u5f53\u7136\u5730\u5c06Index\u6548\u679c\u8ffd\u52a0\u5230\u6bcf\u4e00\u4e2a\u7ec4\u5408\u4e2d\u7684\u5b57\u6bb5\u4e0a\u3002\u5982\u4e0b\u662f -MySQL \u5b98\u65b9\u6587\u6863\u5bf9\u4e8e\u7ec4\u5408\u5b57\u6bb5\u7684Unique Index\u7684\u63cf\u8ff0\u3002<\/p>\n

(\u00a0-R\/u2SN<\/a>\u00a0<\/b> ) \u201cIf the table has a multiple-column index, any leftmost prefix of the index can be used by the optimizer to look up rows. For example, if you have a three-column index on\u00a0(col1, col2, col3)<\/code>, you have indexed search capabilities on\u00a0(col1)<\/code>,\u00a0(col1, col2)<\/code>, and\u00a0(col1, col2, col3)<\/code>.
MySQL cannot use the index to perform lookups if the columns do not form a leftmost prefix of the index. \u201d<\/p>\n

\u7528\u7b80\u7565\u5730\u8bdd\u6765\u8bf4\uff0cUnique Index\u7684Index\u4f5c\u7528\uff1a1\uff09\u5f53\u53ea\u6709\u4e00\u4e2a\u5b57\u6bb5\u65f6\uff0c\u5176Index\u4f5c\u7528\u4e5f\u540c\u6837\u5730\u65bd\u52a0\u5230\u8be5\u5b57\u6bb5\u4e0a\uff1b2\uff09\u5f53\u4e3a\u591a\u4e2a\u5b57\u6bb5\u7684\u7ec4\u5408\u65f6\uff0c\u5176Index\u7684\u4f5c\u7528\uff0c\u53ea\u65bd\u52a0\u5230\u7ec4\u5408\u7684\u7b2c\u4e00\u4e2a\u5b57\u6bb5\u4e0a\u3002<\/p>\n

\u6240\u8c13\u5dee\u4e4b\u6beb\u5398\uff0c\u8c2c\u4e4b\u5343\u91cc\u3002\u5f53\u5f85\u68c0\u7d22\u7684\u5b57\u6bb5\u662f\u67d0\u4e2aUnique Index\u7684\u7ec4\u5408\u5b57\u6bb5\u4e4b\u4e00\uff0c\u4e14\u4e0d\u662f\u7b2c\u4e00\u4e2a\u65f6\uff0c\u88ab\u7528\u505aWhere\u7684\u67e5\u8be2\u6761\u4ef6\uff0c\u67e5\u8be2\u6027\u80fd\u5c06\u6025\u5267\u4e0b\u964d\uff0c\u6bcf\u6b21\u7686\u662f\u5168\u8868\u626b\u63cf\uff0c\u9010\u884c\u5bf9\u6bd4\u3002<\/p>\n

\u8fd9\u79cd\u6027\u80fd\u9690\u60a3\uff0c\u5728\u5f00\u53d1\u521d\u671f\u5e76\u4e0d\u5bb9\u6613\u53d1\u73b0\uff0c\u53ea\u6709\u5f53\u6570\u636e\u91cf\u7ea7\u589e\u957f\u523010M+\u65f6\uff0c\u67e5\u8be2\u8017\u65f6\u624d\u4f1a\u9010\u6b65\u663e\u73b0\u51fa\u6765\u3002<\/p>\n

 <\/p>\n

\"gwa2-logo-201606.v2\"<\/p>\n

-GWA2 \u662f”\u901a\u7528\u7f51\u7edc\u5e94\u7528\u67b6\u6784( General Web Application Architeture )”\uff0c\u57fa\u4e8e -GWA2 \u53ef\u4ee5\u8f7b\u4fbf\u6784\u5efa\u5404\u79cd\u7f51\u7edc\u5e94\u7528\u7a0b\u5e8f,\u00a0
\u5305\u62ec\u590d\u6742\u7684\u5728\u7ebf\u8d2d\u7269\u5546\u57ce\u3001\u00a0\u65c5\u6e38\u4ea4\u6613\u5e73\u53f0\u3001\u793e\u7fa4\u6216\u8005\u793e\u4ea4\u7f51\u7ad9\u548c\u65b0\u95fb\u8d44\u8baf\u7f51\u7ad9\u7b49\uff0c\u00a0
\u4e5f\u5305\u62ec\u5404\u79cd\u4f01\u4e8b\u4e1a\u5355\u4f4d\u7f51\u4e0a\u95e8\u6237\uff0c\u5728\u7ebf\u4ea4\u4e92\u53ca\u670d\u52a1\u4f5c\u4e1a\u7cfb\u7edf\u7b49.\u00a0
\u8fd8\u53ef\u4ee5\u5305\u62ec\u4e3aNativeApp\u505a\u670d\u52a1\u5668\u7aef\u652f\u6301, \u751a\u81f3\u662fWebApp\u7684\u5168\u90e8.
-GWA2 \u662f\u4e3a\u6570\u4e0d\u591a\u7684\u652f\u6301\u8de8\u5f00\u53d1\u8bed\u8a00\u7684\u5e94\u7528\u6846\u67b6\uff0c\u76ee\u524d\u652f\u6301 -Java, -PHP, -Perl, -Aspx and -Python .
-GWA2 is a “General Web Application Architecture”, and based on -GWA2 developers can easily build a variety of network applications,
Including complex online shopping malls, travel trading platforms, community or social networking sites and news information sites, etc.
Also the applications include various enterprises and institutions online portals, online interaction and service operations systems.
And it also includes server-side support for NativeApp, or even all of the WebApp.
-GWA2 is one of the web frameworks which provide cross-language support for -Java, -PHP, -Perl, -Aspx and -Python at present.<\/p>\n

-GWA2 is E.A.S.Y\u00a0<\/strong>
Easy Along, Swift Yield
<\/b>\u8f7b\u677e\u542f\u52a8, \u5feb\u901f\u4ea7\u51fa.\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"

\u5728\u4f7f\u7528 -GWA2 \u8fdb\u884cWebApp\u5f00\u53d1\u65f6\uff0c\u6211\u4eec\u521b\u5efa\u57fa\u4e8eMySQL\u7684\u76f8\u5173\u6570\u636e\u8868\u65f6 … \u7ee7\u7eed\u9605\u8bfb →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":1362,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[42,7,2],"tags":[258,255,257,110,256,259],"_links":{"self":[{"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/posts\/1774"}],"collection":[{"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/comments?post=1774"}],"version-history":[{"count":7,"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/posts\/1774\/revisions"}],"predecessor-version":[{"id":1781,"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/posts\/1774\/revisions\/1781"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/media\/1362"}],"wp:attachment":[{"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/media?parent=1774"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/categories?post=1774"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ufqi.com\/blog\/wp-json\/wp\/v2\/tags?post=1774"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}