{"id":1417,"date":"2021-09-11T22:47:18","date_gmt":"2021-09-11T14:47:18","guid":{"rendered":"https:\/\/blog.odliken.top\/?p=1417"},"modified":"2021-09-11T22:47:18","modified_gmt":"2021-09-11T14:47:18","slug":"mysql%e5%9f%ba%e7%a1%80%e4%b9%8b%e8%a1%a8%e7%9a%84%e7%ae%a1%e7%90%86","status":"publish","type":"post","link":"https:\/\/blog.odjbinail.cn\/?p=1417","title":{"rendered":"MySQL\u57fa\u7840\u4e4b\u8868\u7684\u7ba1\u7406"},"content":{"rendered":"<h2>\u6dfb\u52a0\u548c\u5220\u9664\u5b57\u6bb5\u64cd\u4f5c<\/h2>\n<ul>\n<li>\u6dfb\u52a0\u5b57\u6bb5\uff1aALTER TABLE tbl_name<\/li>\n<li>ADD \u5b57\u6bb5\u540d\u79f0 \u5b57\u6bb5\u5c5e\u6027 [\u5b8c\u6574\u6027\u7ea6\u675f\u6761\u4ef6] [FIRST|AFTER \u5b57\u6bb5\u540d\u79f0]<\/li>\n<li>\u5220\u9664\u5b57\u6bb5 O\uff1aALTER TABLE tbl_name DROP \u5b57\u6bb5\u540d\u79f0<\/li>\n<\/ul>\n<pre class=\"prettyprint linenums\" ><code>-- \u6d4b\u8bd5\u6dfb\u52a0\u548c\u5220\u9664\u5b57\u6bb5\nCREATE TABLE IF NOT EXISTS user1(\n    id INT UNSIGNED AUTO_INCREMENT KEY\n);\n-- \u6dfb\u52a0\u7528\u6237\u540d\u5b57\u6bb5 username VARCHAR(20)\nALTER TABLE user1\nADD username VARCHAR(20);\nDESC user1;\n-- \u6dfb\u52a0\u5bc6\u7801\u5b57\u6bb5 password CHAR(32) NOT NULL\nALTER TABLE user1\nADD password CHAR(32) NOT NULL;\n-- \u6dfb\u52a0\u90ae\u7bb1\u5b57\u6bb5 email VARCHAR(50) NOT NULL UNIQUE \u52a0\u5230 username \u4e4b\u540e\nALTER TABLE user1\nADD email VARCHAR(50) NOT NULL UNIQUE AFTER username;\n-- \u6dfb\u52a0\u6d4b\u8bd5\u5b57\u6bb5 test TINYINT(1) NOT NULL DEFAULT 0; \u52a0\u5230\u9996\u4f4d\nALTER TABLE user1\nADD test TINYINT(1) NOT NULL DEFAULT 0 FIRST;\n-- \u5220\u9664 test \u5b57\u6bb5\nALTER TABLE user1\nDROP test;\n-- \u6dfb\u52a0 age\u3001addr \u5b57\u6bb5\uff0c\u5220\u9664 email \u5b57\u6bb5\nALTER TABLE user1\nADD age TINYINT UNSIGNED NOT NULL DEFAULT 18,\nADD addr VARCHAR(100) NOT NULL DEFAULT &#039;\u5317\u4eac&#039;,\nDROP email;\nDESC user1;\n-- \u521b\u5efa\u6570\u636e\u8868 id \/ proName\n-- \u6dfb\u52a0 price FLOAT(8,2) UNSIGNED NOT NULL DEFAULT 0\n-- \u6dfb\u52a0 num INT UNSIGNED NOT NULL DEFAULT 100\n-- \u6dfb\u52a0\u6d4b\u8bd5\u5b57\u6bb5 test VARCHAR(50) NOT NULL \u52a0\u5230\u9996\u4f4d\n-- \u6dfb\u52a0\u6d4b\u8bd5\u5b57\u6bb5 test1 CHAR(23) NOT NULL \u6dfb\u52a0\u5230 price \u4e4b\u540e\n-- \u5220\u9664 test \u5b57\u6bb5\n-- \u9009\u4e2d\u4e00\u6b21\u6570\u636e\u8868\u5b8c\u6210\u591a\u6b21\u64cd\u4f5c\uff0c\u6dfb\u52a0\u4e00\u4e2a desc TEXT, \u6dfb\u52a0 isSale \u5e03\u5c14\u7c7b\u578b 0 \u4e0b\u67b6 1 \u4ee3\u8868\u5728\u5356\n-- \u5220\u9664 test1 \u5b57\u6bb5<\/code><\/pre>\n<h2>\u6dfb\u52a0\u548c\u5220\u9664\u9ed8\u8ba4\u503c\u64cd\u4f5c<\/h2>\n<ul>\n<li>\u6dfb\u52a0\u9ed8\u8ba4\u503c\uff1aALTER TABLE tbl_name ALTER \u5b57\u6bb5\u540d\u79f0 SET DEFAULT \u9ed8\u8ba4\u503c;<\/li>\n<li>\u5220\u9664\u9ed8\u8ba4\u503c\uff1aALTER TABLE tbl_name ALTER \u5b57\u6bb5\u540d\u79f0 DROP DEFAULT<\/li>\n<\/ul>\n<pre class=\"prettyprint linenums\" ><code>-- \u6d4b\u8bd5\u6dfb\u52a0\u5220\u9664\u9ed8\u8ba4\u503c\u64cd\u4f5c\nCREATE TABLE user2(\nid INT UNSIGNED AUTO_INCREMENT KEY,\nusername VARCHAR(20) NOT NULL,\nage TINYINT UNSIGNED NOT NULL DEFAULT 18,\nemail VARCHAR(50) NOT NULL\n);\n-- \u7ed9 email \u5b57\u6bb5\u6dfb\u52a0\u9ed8\u8ba4\u503c imooc@qq.com\nALTER TABLE user2\nALTER email SET DEFAULT &#039;imooc@qq.com&#039;;\n-- \u5220\u9664 age \u5b57\u6bb5\u7684\u9ed8\u8ba4\u503c\nALTER TABLE user2\nALTER age DROP DEFAULT;\n-- \u6dfb\u52a0\u5730\u5740\u5b57\u6bb5\n-- \u7ed9\u5730\u5740\u5b57\u6bb5\u6dfb\u52a0\u9ed8\u8ba4\u503c\u4e3a\u5317\u4eac\n-- \u5220\u9664\u5546\u54c1\u6570\u91cf\u7684\u9ed8\u8ba4\u503c<\/code><\/pre>\n<h2>MODIFY \u548c CHANGE \u5173\u952e\u5b57\u7684\u4f7f\u7528<\/h2>\n<ul>\n<li>\u4fee\u6539\u5b57\u6bb5\u7c7b\u578b\u3001\u5b57\u6bb5\u5c5e\u6027\uff1aALTER TABLE tbl_name MODIFY \u5b57\u6bb5\u540d\u79f0 \u5b57\u6bb5\u7c7b\u578b [\u5b57\u6bb5\u5c5e\u6027] [FIRST | AFTER \u5b57\u6bb5\u540d\u79f0]<\/li>\n<li>\u4fee\u6539\u5b57\u6bb5\u540d\u79f0\u3001\u5b57\u6bb5\u7c7b\u578b\u3001\u5b57\u6bb5\u5c5e\u6027\uff1aALTER TABLE tbl_name CHANGE \u539f\u5b57\u6bb5\u540d\u79f0 \u65b0\u5b57\u6bb5\u540d\u79f0 \u5b57\u6bb5\u7c7b\u578b \u5b57\u6bb5\u5c5e\u6027 [FIRST | AFTER \u5b57\u6bb5\u540d\u79f0]<\/li>\n<\/ul>\n<pre class=\"prettyprint linenums\" ><code>-- \u6d4b\u8bd5\u4fee\u6539\u5b57\u6bb5\u7c7b\u578b\u548c\u5b57\u6bb5\u5c5e\u6027\u3001\u5b57\u6bb5\u540d\u79f0\nCREATE TABLE user3(\nid INT UNSIGNED AUTO_INCREMENT KEY,\nusername VARCHAR(5) NOT NULL UNIQUE,\npassword CHAR(32) NOT NULL,\nemail VARCHAR(10) NOT NULL\n);\n-- \u5c06\u7528\u6237\u540d\u5b57\u6bb5\u7684\u7c7b\u578b\u6539\u4e3a 20\nALTER TABLE user3\nMODIFY username VARCHAR(20) NOT NULL;\n-- \u5c06\u5bc6\u7801\u7684\u957f\u5ea6\u6539\u4e3a 40\nALTER TABLE user3\nMODIFY password CHAR(40) NOT NULL;\n-- \u5c06 email \u5b57\u6bb5\u6539\u4e3a VARCHAR(50) NOT NULL FIRST\nALTER TABLE user3\nMODIFY email VARCHAR(50) NOT NULL FIRST;\n-- \u5c06 username \u540d\u79f0\u6539\u4e3a user\nALTER TABLE user3\nCHANGE username user VARCHAR(20) NOT NULL;\n-- \u5c06 password \u540d\u79f0\u6539\u4e3a pwd\nALTER TABLE user3\nCHANGE password pwd CHAR(40) NOT NULL;\n-- \u5c06 email \u6539\u6210 userEmail \u7c7b\u578b\u6539\u6210 VARCHAR(100) DEFAULT &#039;imooc@qq.com&#039;\nALTER TABLE user3\nCHANGE email userEmail VARCHAR(100) DEFAULT &#039;imooc@qq.com&#039;;<\/code><\/pre>\n<h2>\u4e3b\u952e\u548c\u552f\u4e00\u7d22\u5f15\u64cd\u4f5c<\/h2>\n<ul>\n<li>\u6dfb\u52a0\u4e3b\u952e\uff1aALTER TABLE tbl_name ADD PRIMARY KEY(\u5b57\u6bb5\u540d\u79f0)<\/li>\n<li>\u5220\u9664\u4e3b\u952e\uff1aALTER TABLE tbl_name DROP PRIMARY KEY;<\/li>\n<\/ul>\n<pre class=\"prettyprint linenums\" ><code>-- \u6d4b\u8bd5\u6dfb\u52a0\u548c\u5220\u9664\u4e3b\u952e\nCREATE TABLE user4(\nid INT UNSIGNED,\nusername VARCHAR(20) NOT NULL\n);\n-- \u6dfb\u52a0\u4e3b\u952e\nALTER TABLE user4\nADD PRIMARY KEY(id);\n-- \u5220\u9664\u4e3b\u952e\nALTER TABLE user4\nDROP PRIMARY KEY;\nCREATE TABLE user5(\nid INT UNSIGNED AUTO_INCREMENT KEY,\nusername VARCHAR(20) NOT NULL\n);\n-- \u5c06 id \u7684 AUTO_INCREMENT \u53bb\u6389,\u5148\u53bb\u6389\uff0c\u624d\u53ef\u4ee5\u53bb\u4e3b\u952e\nALTER TABLE user5\nMODIFY id INT UNSIGNED;\nALTER TABLE user5\nDROP PRIMARY KEY;<\/code><\/pre>\n<ul>\n<li>\u6dfb\u52a0\u552f\u4e00\uff1aALTER TABLE tbl_name ADD UNIQUE KEY | INDEX [index_name] (\u5b57\u6bb5\u540d\u79f0)<\/li>\n<li>\u5220\u9664\u552f\u4e00 \uff1aALTER TABLE tbl_name DROP index_name;<\/li>\n<\/ul>\n<pre class=\"prettyprint linenums\" ><code>-- \u6d4b\u8bd5\u6dfb\u52a0\u548c\u5220\u9664\u552f\u4e00\nCREATE TABLE user6(\nid INT UNSIGNED AUTO_INCREMENT KEY,\nusername VARCHAR(20) NOT NULL UNIQUE,\npassword CHAR(32) NOT NULL,\nemail VARCHAR(50) NOT NULL UNIQUE\n);\nDESC user6;\nSHOW CREATE TABLE user6;\n-- \u5220\u9664\u552f\u4e00\u7d22\u5f15 username \u548c email\nALTER TABLE user6\nDROP INDEX username;\nSHOW CREATE TABLE user6;-- \u67e5\u770b\u8be6\u7ec6\u4fe1\u606f\nALTER TABLE user6\nDROP INDEX email;\n-- \u6dfb\u52a0\u552f\u4e00\u7d22\u5f15\nALTER TABLE user6\nADD UNIQUE KEY(username);\nDESC user6;\nSHOW CREATE TABLE user6;-- \u67e5\u770b\u8be6\u7ec6\u4fe1\u606f\n--\u52a0\u4e0a\u7d22\u5f15\u540d\u79f0\nALTER TABLE user6\nADD UNIQUE INDEX uni_email(email);\nDESC user6;\nSHOW CREATE TABLE user6;-- \u67e5\u770b\u8be6\u7ec6\u4fe1\u606f\n--\u5220\u9664\u7d22\u5f15\u540d\u79f0 UNI\nALTER TABLE user6 DROP  INDEX uni_email;\nDESC user6;<\/code><\/pre>\n<h2>\u91cd\u547d\u540d\u8868\u7684\u64cd\u4f5c<\/h2>\n<ul>\n<li>\u4fee\u6539\u6570\u636e\u8868\u540d\u79f0\uff1aALTER TABLE tbl_name RENAME [TO|AS] new_tbl_name <\/li>\n<li>RENAME TABLE tbl_name TO new_tbl_name;<\/li>\n<\/ul>\n<pre class=\"prettyprint linenums\" ><code>-- \u5c06 user6 \u6539\u4e3a user666\nALTER TABLE user6\nRENAME TO user666;\nSHOW TABLES;\n-- \u5c06 user666 \u6539\u4e3a user6\nALTER TABLE user666\nRENAME AS user6;\nALTER TABLE user6\nRENAME user666;\nRENAME TABLE user666 TO user6;<\/code><\/pre>\n<h2>MyISAM \u5b58\u50a8\u5f15\u64ce<\/h2>\n<ul>\n<li>\u9ed8\u8ba4 MyISAM \u7684\u8868\u4f1a\u5728\u78c1\u76d8\u4e2d\u4ea7\u751f 3 \u4e2a\u6587\u4ef6\uff1a.frm  \u8868\u7ed3\u6784\u6587\u4ef6   .MYD  \u6570\u636e\u6587\u4ef6  .MYI  \u7d22\u5f15\u6587\u4ef6<\/li>\n<li>\u53ef\u4ee5\u5728\u521b\u5efa\u8868\u7684\u65f6\u5019\u6307\u5b9a\u6570\u636e\u6587\u4ef6\u548c\u7d22\u5f15\u6587\u4ef6\u7684\u5b58\u50a8\u4f4d\u7f6e\uff0c\u53ea\u6709 MyISAM \u8868\u652f\u6301\n<ul>\n<li>DATA DIRECORY [=] \u6570\u636e\u4fdd\u5b58\u7684\u7edd\u5bf9\u8def\u5f84<\/li>\n<li>INDEX DIRECTORY[=]\u7d22\u5f15\u6587\u4ef6\u4fdd\u5b58\u7684\u7edd\u5bf9\u8def\u5f84<\/li>\n<\/ul>\n<\/li>\n<li>MyISAM \u5355\u8868\u6700\u5927\u652f\u6301\u7684\u6570\u636e\u91cf 2 \u7684 64 \u6b21\u65b9\u6761\u8bb0\u5f55<\/li>\n<li>\u6bcf\u4e2a\u8868\u6700\u591a\u53ef\u4ee5\u5efa\u7acb 64 \u4e2a\u7d22\u5f15<\/li>\n<li>\u5982\u679c\u662f\u590d\u5408\u7d22\u5f15\uff0c\u6bcf\u4e2a\u590d\u5408\u7d22\u5f15\u6700\u591a\u5305\u542b 16 \u4e2a\u5217\uff0c\u7d22\u5f15\u503c\u6700\u5927\u957f\u5ea6\u662f 1000B<\/li>\n<li>MyISAM \u5f15\u64ce\u7684\u5b58\u50a8\u683c\u5f0f\uff1a<\/li>\n<li>\u5b9a\u957f(FIXED \u9759\u6001) \uff1a\u662f\u6307\u5b57\u6bb5\u4e2d\u4e0d\u5305\u542b VARCHAR\/TEXT\/BLOB<\/li>\n<li>\u52a8\u6001(DYNAMIC )  \uff1a\u53ea\u8981\u5b57\u6bb5\u4e2d\u5305\u542b\u4e86 VARCHAR\/TEXT\/BLOB\u3010\u7a7a\u95f4\u5c11\u3011<\/li>\n<li>\u538b\u7f29(COMPRESSED )\uff1amyisampack \u521b\u5efa<\/li>\n<\/ul>\n<pre class=\"prettyprint linenums\" ><code>-- \u6d4b\u8bd5 MyISAM \u5b58\u50a8\u5f15\u64ce\nCREATE TABLE test_myisam(\n    a INT UNSIGNED,\n    b VARCHAR(20),\n    c CHAR(32)\n)ENGINE=MyISAM;\nSHOW TABLES;\nSHOW CREATE TABLE test_myisam;\n-- \u5b9a\u957f:Row_format:Fixed\nCREATE TABLE myisam_1(\na char(30),\nid int\n)ENGINE=MyISAM;\nSHOW CREATE TABLE myisam_1;\nSHOW TABLE STATUS LIKE &#039;myisam_1&#039;\\G\n-- \u53d8\u957f\uff1aRow_format:Dynamic\nCREATE TABLE myisam_2(\na VARCHAR(30),\nid int\n)ENGINE=MyISAM;\nSHOW TABLE STATUS LIKE &#039;myisam_2&#039;\\G\n--\u53d8\u9759\u6001\u5b9a\u957f\nCREATE TABLE myisam_3(\na VARCHAR(30),\nid int\n)ENGINE=MyISAM ROW_FORMAT=FIXED;<\/code><\/pre>\n<h2>InnoDB \u5b58\u50a8\u5f15\u64ce\u3010\u7528\u7684\u591a\u3011<\/h2>\n<ul>\n<li>\u8bbe\u8ba1\u9075\u5faa ACID \u6a21\u578b\uff0c\u652f\u6301\u4e8b\u52a1\uff0c\u5177\u6709\u4ece\u670d\u52a1\u5954\u6e83\u4e2d\u6062\u590d\u7684\u80fd\u529b\uff0c\u80fd\u591f\u6700\u5927\u9650\u5ea6\u4fdd\u62a4\u7528\u6237\u7684\u6570\u636e\n<ul>\n<li>\u539f\u5b50\u6027( Atomiocity )<\/li>\n<li>\u4e00\u81f4\u6027(Consistency)<\/li>\n<li>\u9694\u79bb\u6027( Isolation )<\/li>\n<li>\u6301\u4e45\u6027(Durability )<\/li>\n<\/ul>\n<\/li>\n<li>\u652f\u6301\u884c\u7ea7\u9501\uff0c\u53ef\u4ee5\u63d0\u5347\u591a\u7528\u6237\u5e76\u53d1\u65f6\u7684\u8bfb\u5199\u6027\u80fd<\/li>\n<li>\u652f\u6301\u5916\u952e\uff0c\u4fdd\u8bc1\u6570\u636e\u7684\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027<\/li>\n<li>InnoDB \u62e5\u6709\u81ea\u5df1\u72ec\u7acb\u7684\u7f13\u51b2\u6c60\uff0c\u5e38\u7528\u7684\u6570\u636e\u548c\u7d22\u5f15\u90fd\u5728\u7f13\u5b58\u4e2d<\/li>\n<li>\u5bf9\u4e8e INSERT\u3001UPDATE\u3001DELETE \u64cd\u4f5c\uff0cInnoDB \u4f1a\u4f7f\u7528\u4e00\u79cd change buffering \u7684\u673a\u5236\u6765\u81ea\u52a8\u4f18\u5316\uff0c\u8fd8\u53ef\u4ee5\u63d0\u4f9b\u4e00\u81f4\u6027\u7684\u8bfb\uff0c\u5e76\u4e14\u8fd8\u80fd\u591f\u7f13\u5b58\u53d8\u66f4\u7684\u6570\u636e\uff0c\u51cf\u5c11\u78c1\u76d8 I\/O\uff0c\u63d0\u9ad8\u6027\u80fd<\/li>\n<li>\u521b\u5efa InnoDB \u8868\u4e4b\u540e\u4f1a\u4ea7\u751f\u4e24\u4e2a\u6587\u4ef6\uff1a\n<ul>\n<li>.frm \u8868\u7ed3\u6784\u6587\u4ef6 <\/li>\n<li>.ibd\uff0c\u6570\u636e\u548c\u7d22\u5f15\u5b58\u50a8\u8868\u7a7a\u95f4\u4e2d<\/li>\n<\/ul>\n<\/li>\n<li>\u6240\u6709\u7684\u8868\u90fd\u9700\u8981\u521b\u5efa\u4e3b\u952e\uff0c\u6700\u597d\u662f\u914d\u5408\u4e0a AUTO_INCREMENT,\u4e5f\u53ef\u4ee5\u653e\u5230\u7ecf\u5e38\u67e5\u8be2\u7684\u5217\u4f5c\u4e3a\u4e3b\u952e<\/li>\n<\/ul>\n<pre class=\"prettyprint linenums\" ><code>CREATE TABLE test_innodb(\n id INT UNSIGNED AUTO_INCREMENT KEY,\n username VARCHAR(20) NOT NULL\n);<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u6dfb\u52a0\u548c\u5220\u9664\u5b57\u6bb5\u64cd\u4f5c \u6dfb\u52a0\u5b57\u6bb5\uff1aALTER TABLE tbl_name ADD \u5b57\u6bb5\u540d\u79f0 \u5b57\u6bb5\u5c5e\u6027 [\u5b8c\u6574\u6027\u7ea6 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-1417","post","type-post","status-publish","format-standard","hentry","category-mysql"],"_links":{"self":[{"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=\/wp\/v2\/posts\/1417","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1417"}],"version-history":[{"count":0,"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=\/wp\/v2\/posts\/1417\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1417"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1417"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.odjbinail.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1417"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}