{"id":1678,"date":"2022-11-23T23:05:43","date_gmt":"2022-11-23T15:05:43","guid":{"rendered":"https:\/\/qaqaq.top\/?p=1678"},"modified":"2022-11-27T12:40:57","modified_gmt":"2022-11-27T04:40:57","slug":"%e4%ba%8b%e5%8a%a1%e7%9a%84acid%e7%89%b9%e6%80%a7%e4%b8%8e%e4%ba%8b%e5%8a%a1%e7%9a%84%e7%8a%b6%e6%80%81%e3%80%81%e6%98%be%e5%bc%8f%e4%ba%8b%e5%8a%a1%e4%b8%8e%e9%9a%90%e5%bc%8f%e4%ba%8b%e5%8a%a1","status":"publish","type":"post","link":"https:\/\/qaqaq.top\/?p=1678","title":{"rendered":"\u4e8b\u52a1\u7684ACID\u7279\u6027\u4e0e\u4e8b\u52a1\u7684\u72b6\u6001\u3001\u663e\u5f0f\u4e8b\u52a1\u4e0e\u9690\u5f0f\u4e8b\u52a1\u3001\u4e8b\u52a1\u7684\u4f7f\u7528\u4e3e\u4f8b\u3001\u6570\u636e\u5e76\u53d1\u95ee\u9898\u4e0e4\u79cd\u9694\u79bb\u7ea7\u522b\u3001MySQL\u9694\u79bb\u7ea7\u522b\u7684\u67e5\u770b\u548c\u8bbe\u7f6e\u3001\u8bfb\u672a\u63d0\u4ea4\u9694\u79bb\u6027\u4e0b\u7684\u6f14\u793a\u3001\u8bfb\u5df2\u63d0\u4ea4\u548c\u53ef\u91cd\u590d\u8bfb\u7684\u9694\u79bb\u6027\u4e0b\u7684\u6f14\u793a\u3001\u5e7b\u8bfb\u7684\u6f14\u793a\u4e0e\u89e3\u51b3\u65b9\u6848"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code># \u7b2c13\u7ae0_\u4e8b\u52a1\u57fa\u7840\u77e5\u8bc6\r\n\r\n# 09-\u4e8b\u7269\u7684\u57fa\u7840\u77e5\u8bc6\r\n\r\n# 1. \u6570\u636e\u5e93\u4e8b\u52a1\u6982\u8ff0\r\n\r\n# 1.1 \u5b58\u50a8\u5f15\u64ce\u652f\u6301\u60c5\u51b5\r\n# SHOW ENGINES \u547d\u4ee4\u6765\u67e5\u770b\u5f53\u524d MySQL \u652f\u6301\u7684\u5b58\u50a8\u5f15\u64ce\u90fd\u6709\u54ea\u4e9b\uff0c\u4ee5\u53ca\u8fd9\u4e9b\u5b58\u50a8\u5f15\u64ce\u662f\u5426\u652f\u6301\u4e8b\u52a1\u3002\r\n\r\n# \u80fd\u770b\u51fa\u5728 MySQL \u4e2d\uff0c\u53ea\u6709InnoDB \u662f\u652f\u6301\u4e8b\u52a1\u7684\u3002\r\n\r\n# 1.2 \u57fa\u672c\u6982\u5ff5\r\n# \u4e8b\u52a1\uff1a\u4e00\u7ec4\u903b\u8f91\u64cd\u4f5c\u5355\u5143\uff0c\u4f7f\u6570\u636e\u4ece\u4e00\u79cd\u72b6\u6001\u53d8\u6362\u5230\u53e6\u4e00\u79cd\u72b6\u6001\u3002\r\n# \u4e8b\u52a1\u5904\u7406\u7684\u539f\u5219\uff1a\u4fdd\u8bc1\u6240\u6709\u4e8b\u52a1\u90fd\u4f5c\u4e3a \u4e00\u4e2a\u5de5\u4f5c\u5355\u5143 \u6765\u6267\u884c\uff0c\u5373\u4f7f\u51fa\u73b0\u4e86\u6545\u969c\uff0c\u90fd\u4e0d\u80fd\u6539\u53d8\u8fd9\u79cd\u6267\u884c\u65b9\u5f0f\u3002\r\n# \u5f53\u5728\u4e00\u4e2a\u4e8b\u52a1\u4e2d\u6267\u884c\u591a\u4e2a\u64cd\u4f5c\u65f6\uff0c\u8981\u4e48\u6240\u6709\u7684\u4e8b\u52a1\u90fd\u88ab\u63d0\u4ea4( commit )\uff0c\u90a3\u4e48\u8fd9\u4e9b\u4fee\u6539\u5c31 \u6c38\u4e45 \u5730\u4fdd\u5b58\u4e0b\u6765\uff1b\r\n# \u8981\u4e48\u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\u5c06 \u653e\u5f03 \u6240\u4f5c\u7684\u6240\u6709 \u4fee\u6539 \uff0c\u6574\u4e2a\u4e8b\u52a1\u56de\u6eda( rollback )\u5230\u6700\u521d\u72b6\u6001\u3002\r\n\r\n# 1.3 \u4e8b\u52a1\u7684ACID\u7279\u6027\r\n# \u539f\u5b50\u6027\uff08atomicity\uff09\uff1a\r\n# \u539f\u5b50\u6027\u662f\u6307\u4e8b\u52a1\u662f\u4e00\u4e2a\u4e0d\u53ef\u5206\u5272\u7684\u5de5\u4f5c\u5355\u4f4d\uff0c\u8981\u4e48\u5168\u90e8\u63d0\u4ea4\uff0c\u8981\u4e48\u5168\u90e8\u5931\u8d25\u56de\u6eda\u3002\r\n\r\n# \u4e00\u81f4\u6027\uff08consistency\uff09\uff1a\r\n# \uff08\u56fd\u5185\u5f88\u591a\u7f51\u7ad9\u4e0a\u5bf9\u4e00\u81f4\u6027\u7684\u9610\u8ff0\u6709\u8bef\uff0c\u5177\u4f53\u4f60\u53ef\u4ee5\u53c2\u8003 Wikipedia \u5bf9Consistency\u7684\u9610\u8ff0\uff09\u6839\u636e\u5b9a\u4e49\uff0c\r\n# \u4e00\u81f4\u6027\u662f\u6307\u4e8b\u52a1\u6267\u884c\u524d\u540e\uff0c\u6570\u636e\u4ece\u4e00\u4e2a \u5408\u6cd5\u6027\u72b6\u6001 \u53d8\u6362\u5230\u53e6\u5916\u4e00\u4e2a \u5408\u6cd5\u6027\u72b6\u6001 \u3002\r\n# \u8fd9\u79cd\u72b6\u6001\u662f \u8bed\u4e49\u4e0a \u7684\u800c\u4e0d\u662f\u8bed\u6cd5\u4e0a\u7684\uff0c\u8ddf\u5177\u4f53\u7684\u4e1a\u52a1\u6709\u5173\u3002\r\n\r\n# \u90a3\u4ec0\u4e48\u662f\u5408\u6cd5\u7684\u6570\u636e\u72b6\u6001\u5462\uff1f\u6ee1\u8db3 \u9884\u5b9a\u7684\u7ea6\u675f \u7684\u72b6\u6001\u5c31\u53eb\u505a\u5408\u6cd5\u7684\u72b6\u6001\u3002\u901a\u4fd7\u4e00\u70b9\uff0c\r\n# \u8fd9\u72b6\u6001\u662f\u7531\u4f60\u81ea\u5df1\u6765\u5b9a\u4e49\u7684\uff08\u6bd4\u5982\u6ee1\u8db3\u73b0\u5b9e\u4e16\u754c\u4e2d\u7684\u7ea6\u675f\uff09\u3002\u6ee1\u8db3\u8fd9\u4e2a\u72b6\u6001\uff0c\u6570\u636e\u5c31\u662f\u4e00\u81f4\u7684\uff0c\u4e0d\u6ee1\u8db3\u8fd9\u4e2a\u72b6\u6001\uff0c\r\n# \u6570\u636e\u5c31\u662f\u4e0d\u4e00\u81f4\u7684\uff01\u5982\u679c\u4e8b\u52a1\u4e2d\u7684\u67d0\u4e2a\u64cd\u4f5c\u5931\u8d25\u4e86\uff0c\u7cfb\u7edf\u5c31\u4f1a\u81ea\u52a8\u64a4\u9500\u5f53\u524d\u6b63\u5728\u6267\u884c\u7684\u4e8b\u52a1\uff0c\r\n# \u8fd4\u56de\u5230\u4e8b\u52a1\u64cd\u4f5c\u4e4b\u524d\u7684\u72b6\u6001\u3002\r\n\r\n# \u9694\u79bb\u578b\uff08isolation\uff09\uff1a\r\n# \u4e8b\u52a1\u7684\u9694\u79bb\u6027\u662f\u6307\u4e00\u4e2a\u4e8b\u52a1\u7684\u6267\u884c \u4e0d\u80fd\u88ab\u5176\u4ed6\u4e8b\u52a1\u5e72\u6270 \uff0c\r\n# \u5373\u4e00\u4e2a\u4e8b\u52a1\u5185\u90e8\u7684\u64cd\u4f5c\u53ca\u4f7f\u7528\u7684\u6570\u636e\u5bf9 \u5e76\u53d1 \u7684\u5176\u4ed6\u4e8b\u52a1\u662f\u9694\u79bb\u7684\uff0c\u5e76\u53d1\u6267\u884c\u7684\u5404\u4e2a\u4e8b\u52a1\u4e4b\u95f4\u4e0d\u80fd\u4e92\u76f8\u5e72\u6270\u3002\r\n\r\n# \u6301\u4e45\u6027\uff08durability\uff09\uff1a\r\n# \u6301\u4e45\u6027\u662f\u6307\u4e00\u4e2a\u4e8b\u52a1\u4e00\u65e6\u88ab\u63d0\u4ea4\uff0c\u5b83\u5bf9\u6570\u636e\u5e93\u4e2d\u6570\u636e\u7684\u6539\u53d8\u5c31\u662f \u6c38\u4e45\u6027\u7684 \uff0c\r\n# \u63a5\u4e0b\u6765\u7684\u5176\u4ed6\u64cd\u4f5c\u548c\u6570\u636e\u5e93\u6545\u969c\u4e0d\u5e94\u8be5\u5bf9\u5176\u6709\u4efb\u4f55\u5f71\u54cd\u3002\r\n\r\n# \u6301\u4e45\u6027\u662f\u901a\u8fc7 \u4e8b\u52a1\u65e5\u5fd7 \u6765\u4fdd\u8bc1\u7684\u3002\u65e5\u5fd7\u5305\u62ec\u4e86 \u91cd\u505a\u65e5\u5fd7 \u548c \u56de\u6eda\u65e5\u5fd7 \u3002\u5f53\u6211\u4eec\u901a\u8fc7\u4e8b\u52a1\u5bf9\u6570\u636e\u8fdb\u884c\u4fee\u6539\u7684\u65f6\u5019\uff0c\r\n# \u9996\u5148\u4f1a\u5c06\u6570\u636e\u5e93\u7684\u53d8\u5316\u4fe1\u606f\u8bb0\u5f55\u5230\u91cd\u505a\u65e5\u5fd7\u4e2d\uff0c\u7136\u540e\u518d\u5bf9\u6570\u636e\u5e93\u4e2d\u5bf9\u5e94\u7684\u884c\u8fdb\u884c\u4fee\u6539\u3002\u8fd9\u6837\u505a\u7684\u597d\u5904\u662f\uff0c\r\n# \u5373\u4f7f\u6570\u636e\u5e93\u7cfb\u7edf\u5d29\u6e83\uff0c\u6570\u636e\u5e93\u91cd\u542f\u540e\u4e5f\u80fd\u627e\u5230\u6ca1\u6709\u66f4\u65b0\u5230\u6570\u636e\u5e93\u7cfb\u7edf\u4e2d\u7684\u91cd\u505a\u65e5\u5fd7\uff0c\u91cd\u65b0\u6267\u884c\uff0c\u4ece\u800c\u4f7f\u4e8b\u52a1\u5177\u6709\u6301\u4e45\u6027\u3002\r\n\r\n# 1.4 \u4e8b\u52a1\u7684\u72b6\u6001\r\n# \u6211\u4eec\u73b0\u5728\u77e5\u9053 \u4e8b\u52a1 \u662f\u4e00\u4e2a\u62bd\u8c61\u7684\u6982\u5ff5\uff0c\u5b83\u5176\u5b9e\u5bf9\u5e94\u7740\u4e00\u4e2a\u6216\u591a\u4e2a\u6570\u636e\u5e93\u64cd\u4f5c\uff0c\r\n# MySQL\u6839\u636e\u8fd9\u4e9b\u64cd\u4f5c\u6240\u6267\u884c\u7684\u4e0d\u540c\u9636\u6bb5\u628a \u4e8b\u52a1 \u5927\u81f4\u5212\u5206\u6210\u51e0\u4e2a\u72b6\u6001\uff1a\r\n\r\n# \u6d3b\u52a8\u7684\uff08active\uff09\r\n# \u4e8b\u52a1\u5bf9\u5e94\u7684\u6570\u636e\u5e93\u64cd\u4f5c\u6b63\u5728\u6267\u884c\u8fc7\u7a0b\u4e2d\u65f6\uff0c\u6211\u4eec\u5c31\u8bf4\u8be5\u4e8b\u52a1\u5904\u5728 \u6d3b\u52a8\u7684 \u72b6\u6001\u3002\r\n\r\n# \u90e8\u5206\u63d0\u4ea4\u7684\uff08partially committed\uff09\r\n# \u5f53\u4e8b\u52a1\u4e2d\u7684\u6700\u540e\u4e00\u4e2a\u64cd\u4f5c\u6267\u884c\u5b8c\u6210\uff0c\u4f46\u7531\u4e8e\u64cd\u4f5c\u90fd\u5728\u5185\u5b58\u4e2d\u6267\u884c\uff0c\u6240\u9020\u6210\u7684\u5f71\u54cd\u5e76 \u6ca1\u6709\u5237\u65b0\u5230\u78c1\u76d8\u65f6\uff0c\r\n# \u6211\u4eec\u5c31\u8bf4\u8be5\u4e8b\u52a1\u5904\u5728 \u90e8\u5206\u63d0\u4ea4\u7684 \u72b6\u6001\u3002\r\n\r\n# \u5931\u8d25\u7684\uff08failed\uff09\r\n# \u5f53\u4e8b\u52a1\u5904\u5728 \u6d3b\u52a8\u7684 \u6216\u8005 \u90e8\u5206\u63d0\u4ea4\u7684 \u72b6\u6001\u65f6\uff0c\u53ef\u80fd\u9047\u5230\u4e86\u67d0\u4e9b\u9519\u8bef\r\n# \uff08\u6570\u636e\u5e93\u81ea\u8eab\u7684\u9519\u8bef\u3001\u64cd\u4f5c\u7cfb\u7edf\u9519\u8bef\u6216\u8005\u76f4\u63a5\u65ad\u7535\u7b49\uff09\u800c\u65e0\u6cd5\u7ee7\u7eed\u6267\u884c\uff0c\u6216\u8005\u4eba\u4e3a\u7684\u505c\u6b62\u5f53\u524d\u4e8b\u52a1\u7684\u6267\u884c\uff0c\r\n# \u6211\u4eec\u5c31\u8bf4\u8be5\u4e8b\u52a1\u5904\u5728 \u5931\u8d25\u7684 \u72b6\u6001\u3002\r\n\r\n# \u4e2d\u6b62\u7684\uff08aborted\uff09\r\n# \u5982\u679c\u4e8b\u52a1\u6267\u884c\u4e86\u4e00\u90e8\u5206\u800c\u53d8\u4e3a \u5931\u8d25\u7684 \u72b6\u6001\uff0c\u90a3\u4e48\u5c31\u9700\u8981\u628a\u5df2\u7ecf\u4fee\u6539\u7684\u4e8b\u52a1\u4e2d\u7684\u64cd\u4f5c\u8fd8\u539f\u5230\u4e8b\u52a1\u6267\u884c\u524d\u7684\u72b6\u6001\u3002\r\n# \u6362\u53e5\u8bdd\u8bf4\uff0c\u5c31\u662f\u8981\u64a4\u9500\u5931\u8d25\u4e8b\u52a1\u5bf9\u5f53\u524d\u6570\u636e\u5e93\u9020\u6210\u7684\u5f71\u54cd\u3002\u6211\u4eec\u628a\u8fd9\u4e2a\u64a4\u9500\u7684\u8fc7\u7a0b\u79f0\u4e4b\u4e3a \u56de\u6eda \u3002\r\n# \u5f53 \u56de\u6eda \u64cd\u4f5c\u6267\u884c\u5b8c\u6bd5\u65f6\uff0c\u4e5f\u5c31\u662f\u6570\u636e\u5e93\u6062\u590d\u5230\u4e86\u6267\u884c\u4e8b\u52a1\u4e4b\u524d\u7684\u72b6\u6001\uff0c\u6211\u4eec\u5c31\u8bf4\u8be5\u4e8b\u52a1\u5904\u5728\u4e86 \u4e2d\u6b62\u7684 \u72b6\u6001\u3002\r\n\r\n# \u63d0\u4ea4\u7684\uff08committed\uff09\r\n# \u5f53\u4e00\u4e2a\u5904\u5728 \u90e8\u5206\u63d0\u4ea4\u7684 \u72b6\u6001\u7684\u4e8b\u52a1\u5c06\u4fee\u6539\u8fc7\u7684\u6570\u636e\u90fd \u540c\u6b65\u5230\u78c1\u76d8 \u4e0a\u4e4b\u540e\uff0c\r\n# \u6211\u4eec\u5c31\u53ef\u4ee5\u8bf4\u8be5\u4e8b\u52a1\u5904\u5728\u4e86 \u63d0\u4ea4\u7684 \u72b6\u6001\u3002\r\n\r\n# 2. \u5982\u4f55\u4f7f\u7528\u4e8b\u52a1\r\n\r\n# \u4f7f\u7528\u4e8b\u52a1\u6709\u4e24\u79cd\u65b9\u5f0f\uff0c\u5206\u522b\u4e3a \u663e\u5f0f\u4e8b\u52a1 \u548c \u9690\u5f0f\u4e8b\u52a1 \u3002\r\n\r\n#\u4e8b\u52a1\u7684\u5b8c\u6210\u8fc7\u7a0b\r\n#\u6b65\u9aa41\uff1a\u5f00\u542f\u4e8b\u52a1\r\n#\u6b65\u9aa42\uff1a\u4e00\u7cfb\u5217\u7684DML\u64cd\u4f5c\r\n# ....\r\n#\u6b65\u9aa43\uff1a\u4e8b\u52a1\u7ed3\u675f\u7684\u72b6\u6001\uff1a\u63d0\u4ea4\u7684\u72b6\u6001\uff08COMMIT\uff09\u3001\u4e2d\u6b62\u7684\u72b6\u6001\uff08ROLLBACK\uff09\r\n\r\n# 2.1 \u663e\u5f0f\u4e8b\u52a1\r\n\r\n# \u2460 \u5982\u4f55\u5f00\u542f\uff1f\u4f7f\u7528\u5173\u952e\u5b57\uff1astart transaction \u6216 begin\r\n\r\n# start transaction \u540e\u9762\u53ef\u4ee5\u8ddf\uff1aread only \/ read write \uff08\u9ed8\u8ba4\uff09\/with consistent snapshot\r\n\r\n# \u2160 READ ONLY \uff1a\u6807\u8bc6\u5f53\u524d\u4e8b\u52a1\u662f\u4e00\u4e2a \u53ea\u8bfb\u4e8b\u52a1 \uff0c\u4e5f\u5c31\u662f\u5c5e\u4e8e\u8be5\u4e8b\u52a1\u7684\u6570\u636e\u5e93\u64cd\u4f5c\u53ea\u80fd\u8bfb\u53d6\u6570\u636e\uff0c\u800c\u4e0d\u80fd\u4fee\u6539\u6570\u636e\u3002\r\n# \u2161 READ WRITE \uff1a\u6807\u8bc6\u5f53\u524d\u4e8b\u52a1\u662f\u4e00\u4e2a \u8bfb\u5199\u4e8b\u52a1 \uff0c\u4e5f\u5c31\u662f\u5c5e\u4e8e\u8be5\u4e8b\u52a1\u7684\u6570\u636e\u5e93\u64cd\u4f5c\u65e2\u53ef\u4ee5\u8bfb\u53d6\u6570\u636e\uff0c\u4e5f\u53ef\u4ee5\u4fee\u6539\u6570\u636e\u3002\r\n# \u2162 WITH CONSISTENT SNAPSHOT \uff1a\u542f\u52a8\u4e00\u81f4\u6027\u8bfb\u3002\r\n\r\n# \u2461 \u4fdd\u5b58\u70b9\uff08savepoint\uff09\r\n# \u5728\u4e8b\u52a1\u4e2d\u521b\u5efa\u4fdd\u5b58\u70b9\uff0c\u65b9\u4fbf\u540e\u7eed\u9488\u5bf9\u4fdd\u5b58\u70b9\u8fdb\u884c\u56de\u6eda\u3002\u4e00\u4e2a\u4e8b\u52a1\u4e2d\u53ef\u4ee5\u5b58\u5728\u591a\u4e2a\u4fdd\u5b58\u70b9\u3002\r\n# SAVEPOINT \u4fdd\u5b58\u70b9\u540d\u79f0;\r\n\r\n# \u5220\u9664\u67d0\u4e2a\u4fdd\u5b58\u70b9\u3002\r\n# RELEASE SAVEPOINT \u4fdd\u5b58\u70b9\u540d\u79f0;\r\n\r\n# 2.2 \u9690\u5f0f\u4e8b\u52a1\r\n\r\n# \u2460 \u5173\u952e\u5b57 autocommit\r\n# SET AUTOCOMMIT = FALSE;\r\n\r\nSHOW VARIABLES LIKE 'autocommit';   #\u9ed8\u8ba4\u662fON\r\n\r\nUPDATE account SET balance = balance - 10 WHERE id = 1; #\u6b64\u65f6\u8fd9\u6761DML\u64cd\u4f5c\u662f\u4e00\u4e2a\u72ec\u7acb\u7684\u4e8b\u52a1\r\n\r\nUPDATE account SET balance = balance + 10 WHERE id = 2; #\u6b64\u65f6\u8fd9\u6761DML\u64cd\u4f5c\u662f\u4e00\u4e2a\u72ec\u7acb\u7684\u4e8b\u52a1\r\n\r\n# \u2461 \u5982\u4f55\u5173\u95ed\u81ea\u52a8\u63d0\u4ea4\uff1f\r\n# \u65b9\u5f0f1\uff1a\r\nSET AUTOCOMMIT = FALSE; #\u9488\u5bf9\u4e0eDML\u64cd\u4f5c\u662f\u6709\u6548\u7684\uff0c\u5bf9DDL\u64cd\u4f5c\u662f\u65e0\u6548\u7684\u3002\r\n\r\nUPDATE account SET balance = balance - 10 WHERE id = 1;\r\n\r\nUPDATE account SET balance = balance + 10 WHERE id = 2;\r\n\r\nCOMMIT # \u6216rollback;\r\n\r\n#\u65b9\u5f0f2\uff1a\u6211\u4eec\u5728autocommit\u4e3atrue\u7684\u60c5\u51b5\u4e0b\uff0c\u4f7f\u7528start transaction \u6216begin \u5f00\u542f\u4e8b\u52a1\uff0c\r\n# \u90a3\u4e48DML\u64cd\u4f5c\u5c31\u4e0d\u4f1a\u81ea\u52a8\u63d0\u4ea4\u6570\u636e\r\n\r\nSTART TRANSACTION;\r\n\r\nUPDATE account SET balance = balance - 10 WHERE id = 1;\r\n\r\nUPDATE account SET balance = balance + 10 WHERE id = 2;\r\n\r\nCOMMIT # \u6216rollback\r\n\r\n# 2.3 \u9690\u5f0f\u63d0\u4ea4\u6570\u636e\u7684\u60c5\u51b5\r\n\r\n# \u6570\u636e\u5b9a\u4e49\u8bed\u8a00\uff08Data definition language\uff0c\u7f29\u5199\u4e3a\uff1aDDL\uff09\r\n\r\n# \u9690\u5f0f\u4f7f\u7528\u6216\u4fee\u6539mysql\u6570\u636e\u5e93\u4e2d\u7684\u8868\r\n\r\n# \u4e8b\u52a1\u63a7\u5236\u6216\u5173\u4e8e\u9501\u5b9a\u7684\u8bed\u53e5\r\n#     \u2460 \u5f53\u6211\u4eec\u5728\u4e00\u4e2a\u4e8b\u52a1\u8fd8\u6ca1\u63d0\u4ea4\u6216\u8005\u56de\u6eda\u65f6\u5c31\u53c8\u4f7f\u7528 START TRANSACTION \u6216\u8005 BEGIN \u8bed\u53e5\u5f00\u542f\u4e86\u53e6\u4e00\u4e2a\u4e8b\u52a1\u65f6\uff0c\r\n# \u4f1a \u9690\u5f0f\u7684\u63d0\u4ea4 \u4e0a\u4e00\u4e2a\u4e8b\u52a1\u3002\u5373\uff1a\r\n#     \u2461 \u5f53\u524d\u7684 autocommit \u7cfb\u7edf\u53d8\u91cf\u7684\u503c\u4e3a OFF \uff0c\u6211\u4eec\u624b\u52a8\u628a\u5b83\u8c03\u4e3a ON \u65f6\uff0c\r\n# \u4e5f\u4f1a \u9690\u5f0f\u7684\u63d0\u4ea4 \u524d\u8fb9\u8bed\u53e5\u6240\u5c5e\u7684\u4e8b\u52a1\u3002\r\n#     \u2462 \u4f7f\u7528 LOCK TABLES \u3001 UNLOCK TABLES \u7b49\u5173\u4e8e\u9501\u5b9a\u7684\u8bed\u53e5\u4e5f\u4f1a \u9690\u5f0f\u7684\u63d0\u4ea4 \u524d\u8fb9\u8bed\u53e5\u6240\u5c5e\u7684\u4e8b\u52a1\u3002\r\n\r\n# \u52a0\u8f7d\u6570\u636e\u7684\u8bed\u53e5\r\n\r\n# \u5173\u4e8eMySQL\u590d\u5236\u7684\u4e00\u4e9b\u8bed\u53e5\r\n\r\n# \u5176\u5b83\u7684\u4e00\u4e9b\u8bed\u53e5\r\n\r\n# \u6848\u4f8b\u5206\u6790\r\nSET AUTOCOMMIT = TRUE;\r\n\r\n# 2.4 \u4f7f\u7528\u4e3e\u4f8b1\uff1a\u63d0\u4ea4\u4e0e\u56de\u6eda\r\n#\u4e3e\u4f8b1\uff1acommit \u548c rollback\r\n\r\nUSE atguigudb2;\r\n\r\n#\u60c5\u51b51\uff1a\r\nCREATE TABLE user3(name VARCHAR(15) PRIMARY KEY);\r\n\r\nSELECT * FROM user3;\r\n\r\nBEGIN;\r\nINSERT INTO user3 VALUES('\u5f20\u4e09'); #\u6b64\u65f6\u4e0d\u4f1a\u81ea\u52a8\u63d0\u4ea4\u6570\u636e\r\nCOMMIT;\r\n\r\nBEGIN;  #\u5f00\u542f\u4e00\u4e2a\u65b0\u7684\u4e8b\u52a1\r\nINSERT INTO user3 VALUES('\u674e\u56db');\r\nINSERT INTO user3 VALUES('\u674e\u56db'); #\u53d7\u4e3b\u952e\u7684\u5f71\u54cd\uff0c\u4e0d\u80fd\u6dfb\u52a0\u6210\u529f\r\nROLLBACK;\r\n\r\nSELECT * FROM user3;\r\n\r\n#\u60c5\u51b52\uff1a\r\nTRUNCATE TABLE user3;    #DDL\u64cd\u4f5c\u4f1a\u81ea\u52a8\u63d0\u4ea4\u6570\u636e\uff0c\u4e0d\u53d7autocommit\u53d8\u91cf\u7684\u5f71\u54cd\u3002\r\n\r\nSELECT * FROM user3;\r\n\r\nBEGIN;\r\nINSERT INTO user3 VALUES('\u5f20\u4e09');\r\nCOMMIT;\r\n\r\nINSERT INTO user3 VALUES('\u674e\u56db'); #\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff08\u5373autocommit\u4e3atrue\uff09\uff0cDML\u64cd\u4f5c\u4e5f\u4f1a\u81ea\u52a8\u63d0\u4ea4\u6570\u636e\u3002\r\nINSERT INTO user3 VALUES('\u674e\u56db'); #\u4e8b\u52a1\u662f\u5931\u8d25\u7684\u72b6\u6001\r\n\r\nROLLBACK;\r\n\r\nSELECT * FROM user3;\r\n\r\n#\u60c5\u51b53\uff1a\r\nTRUNCATE TABLE user3;\r\n\r\nSELECT * FROM user3;\r\n\r\nSELECT @@completion_type;\r\n\r\nSET @@completion_type = 1;\r\n\r\nBEGIN;\r\nINSERT INTO user3 VALUES('\u5f20\u4e09');\r\nCOMMIT;\r\n\r\nSELECT * FROM user3;\r\n\r\nINSERT INTO user3 VALUES('\u674e\u56db');\r\nINSERT INTO user3 VALUES('\u674e\u56db');\r\n\r\nROLLBACK;\r\n\r\nSELECT * FROM user3;\r\n\r\n# MySQL\u4e2dcompletion_type\u53c2\u6570\u7684\u4f5c\u7528\uff0c\u5b9e\u9645\u4e0a\u8fd9\u4e2a\u53c2\u6570\u67093\u79cd\u53ef\u80fd\uff1a\r\n# 1. completion_type=1\uff0c\u8fd9\u662f\u9ed8\u8ba4\u60c5\u51b5\u3002\u5f53\u6211\u4eec\u6267\u884cCOMMIT\u7684\u65f6\u5019\u4f1a\u63d0\u4ea4\u4e8b\u52a1\uff0c\u5728\u6267\u884c\u4e0b\u4e00\u4e2a\u4e8b\u52a1\u65f6\uff0c\r\n# \u8fd8\u9700\u8981\u4f7f\u7528START TRANSACTION \u6216\u8005 BEGIN \u6765\u5f00\u542f\u3002\r\n\r\n# 2. completion_type=1\uff0c\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u5f53\u6211\u4eec\u63d0\u4ea4\u4e8b\u52a1\u540e\uff0c\u76f8\u5f53\u4e8e\u6267\u884c\u4e86COMMIT AND CHAIN\uff0c\r\n# \u4e5f\u5c31\u662f\u5f00\u542f\u4e00\u4e2a\u94fe\u5f0f\u4e8b\u52a1\uff0c\u5373\u5f53\u6211\u4eec\u63d0\u4ea4\u4e8b\u52a1\u4e4b\u540e\u4f1a\u5f00\u542f\u4e00\u4e2a\u76f8\u540c\u9694\u79bb\u7ea7\u522b\u7684\u4e8b\u52a1\u3002\r\n\r\n# 3. completion_type=2\uff0c\u8fd9\u79cd\u60c5\u51b5\u4e0b COMMIT = COMMIT AND RELEASE\uff0c\u4e5f\u5c31\u662f\u5f53\u6211\u4eec\u63d0\u4ea4\u540e\uff0c\r\n# \u4f1a\u81ea\u52a8\u4e0e\u670d\u52a1\u5668\u65ad\u5f00\u8fde\u63a5\u3002\r\n\r\n# \u5f53\u6211\u4eec\u8bbe\u7f6e autocommit=0 \u65f6\uff0c\u4e0d\u8bba\u662f\u5426\u91c7\u7528 START TRANSACTION \u6216\u8005 BEGIN \u7684\u65b9\u5f0f\u6765\u5f00\u542f\u4e8b\u52a1\uff0c\r\n# \u90fd\u9700\u8981\u7528 COMMIT \u8fdb\u884c\u63d0\u4ea4\uff0c\u8ba9\u4e8b\u52a1\u751f\u6548\uff0c\u4f7f\u7528 ROLLBACK \u5bf9\u4e8b\u52a1\u8fdb\u884c\u56de\u6eda\u3002\r\n\r\n# \u5f53\u6211\u4eec\u8bbe\u7f6e autocommit=1 \u65f6\uff0c\u6bcf\u6761 SQL \u8bed\u53e5\u90fd\u4f1a\u81ea\u52a8\u8fdb\u884c\u63d0\u4ea4\u3002 \u4e0d\u8fc7\u8fd9\u65f6\uff0c\r\n# \u5982\u679c\u4f60\u91c7\u7528 START TRANSACTION \u6216\u8005 BEGIN \u7684\u65b9\u5f0f\u6765\u663e\u5f0f\u5730\u5f00\u542f\u4e8b\u52a1\uff0c\r\n# \u90a3\u4e48\u8fd9\u4e2a\u4e8b\u52a1\u53ea\u6709\u5728 COMMIT \u65f6\u624d\u4f1a\u751f\u6548\uff0c\u5728 ROLLBACK \u65f6\u624d\u4f1a\u56de\u6eda\u3002\r\n\r\n# \u4f7f\u7528\u4e3e\u4f8b2\uff1a\u6d4b\u8bd5\u4e0d\u652f\u6301\u4e8b\u52a1\u7684engine\r\n#\u4e3e\u4f8b2\uff1a\u4f53\u4f1aINNODB \u548c MyISAM\r\n\r\nCREATE TABLE test1(i INT) ENGINE = INNODB;\r\n\r\nCREATE TABLE test2(i INT) ENGINE = MYISAM;\r\n\r\n#\u9488\u5bf9\u4e8einnodb\u8868\r\nBEGIN;\r\nINSERT INTO test1 VALUES (1);\r\nROLLBACK;\r\n\r\nSELECT * FROM test1;\r\n\r\n#\u9488\u5bf9\u4e8emyisam\u8868:\u4e0d\u652f\u6301\u4e8b\u52a1\r\nBEGIN;\r\nINSERT INTO test2 VALUES (1);\r\nROLLBACK;\r\n\r\nSELECT * FROM test2;\r\n\r\n# \u4f7f\u7528\u4e3e\u4f8b3\uff1aSAVEPOINT\r\n#\u4e3e\u4f8b3\uff1a\u4f53\u4f1asavepoint\r\n\r\nUSE atguigudb3;\r\n\r\nCREATE TABLE user3(name VARCHAR(15),balance DECIMAL(10,2));\r\n\r\nBEGIN;\r\nINSERT INTO user3(name, balance) VALUES ('\u5f20\u4e09',1000);\r\nCOMMIT;\r\n\r\nSELECT * FROM user3;\r\n\r\nBEGIN;\r\nUPDATE user3 SET balance = balance - 100 WHERE name = '\u5f20\u4e09';\r\n\r\nUPDATE user3 SET balance = balance - 100 WHERE name = '\u5f20\u4e09';\r\n\r\nSAVEPOINT s1;   #\u8bbe\u7f6e\u4fdd\u5b58\u70b9\r\n\r\nUPDATE user3 SET balance = balance + 1 WHERE name = '\u5f20\u4e09';\r\n\r\nROLLBACK TO s1; #\u56de\u6eda\u5230\u4fdd\u5b58\u70b9\r\n\r\nSELECT * FROM user3;\r\n\r\nROLLBACK;    #\u56de\u6eda\u64cd\u4f5c\r\n\r\n# 3. \u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\r\n\r\n# MySQL\u662f\u4e00\u4e2a \u5ba2\u6237\u7aef\uff0f\u670d\u52a1\u5668 \u67b6\u6784\u7684\u8f6f\u4ef6\uff0c\u5bf9\u4e8e\u540c\u4e00\u4e2a\u670d\u52a1\u5668\u6765\u8bf4\uff0c\u53ef\u4ee5\u6709\u82e5\u5e72\u4e2a\u5ba2\u6237\u7aef\u4e0e\u4e4b\u8fde\u63a5\uff0c\r\n# \u6bcf\u4e2a\u5ba2\u6237\u7aef\u4e0e\u670d\u52a1\u5668\u8fde\u63a5\u4e0a\u4e4b\u540e\uff0c\u5c31\u53ef\u4ee5\u79f0\u4e3a\u4e00\u4e2a\u4f1a\u8bdd\uff08 Session \uff09\u3002\r\n# \u6bcf\u4e2a\u5ba2\u6237\u7aef\u90fd\u53ef\u4ee5\u5728\u81ea\u5df1\u7684\u4f1a\u8bdd\u4e2d\u5411\u670d\u52a1\u5668\u53d1\u51fa\u8bf7\u6c42\u8bed\u53e5\uff0c\u4e00\u4e2a\u8bf7\u6c42\u8bed\u53e5\u53ef\u80fd\u662f\u67d0\u4e2a\u4e8b\u52a1\u7684\u4e00\u90e8\u5206\uff0c\r\n# \u4e5f\u5c31\u662f\u5bf9\u4e8e\u670d\u52a1\u5668\u6765\u8bf4\u53ef\u80fd\u540c\u65f6\u5904\u7406\u591a\u4e2a\u4e8b\u52a1\u3002\u4e8b\u52a1\u6709 \u9694\u79bb\u6027 \u7684\u7279\u6027\uff0c\u7406\u8bba\u4e0a\u5728\u67d0\u4e2a\u4e8b\u52a1 \u5bf9\u67d0\u4e2a\u6570\u636e\u8fdb\u884c\u8bbf\u95ee \u65f6\uff0c\r\n# \u5176\u4ed6\u4e8b\u52a1\u5e94\u8be5\u8fdb\u884c \u6392\u961f \uff0c\u5f53\u8be5\u4e8b\u52a1\u63d0\u4ea4\u4e4b\u540e\uff0c\u5176\u4ed6\u4e8b\u52a1\u624d\u53ef\u4ee5\u7ee7\u7eed\u8bbf\u95ee\u8fd9\u4e2a\u6570\u636e\u3002\u4f46\u662f\u8fd9\u6837\u5bf9 \u6027\u80fd\u5f71\u54cd\u592a\u5927 \uff0c\r\n# \u6211\u4eec\u65e2\u60f3\u4fdd\u6301\u4e8b\u52a1\u7684\u9694\u79bb\u6027\uff0c\u53c8\u60f3\u8ba9\u670d\u52a1\u5668\u5728\u5904\u7406\u8bbf\u95ee\u540c\u4e00\u6570\u636e\u7684\u591a\u4e2a\u4e8b\u52a1\u65f6 \u6027\u80fd\u5c3d\u91cf\u9ad8\u4e9b \uff0c\r\n# \u90a3\u5c31\u770b\u4e8c\u8005\u5982\u4f55\u6743\u8861\u53d6\u820d\u4e86\u3002\r\n\r\n# 3.2 \u6570\u636e\u5e76\u53d1\u95ee\u9898\r\n\r\n# \u9488\u5bf9\u4e8b\u52a1\u7684\u9694\u79bb\u6027\u548c\u5e76\u53d1\u6027\uff0c\u6211\u4eec\u600e\u4e48\u505a\u53d6\u820d\u5462\uff1f\r\n# \u5148\u770b\u4e00\u4e0b\u8bbf\u95ee\u76f8\u540c\u6570\u636e\u7684\u4e8b\u52a1\u5728 \u4e0d\u4fdd\u8bc1\u4e32\u884c\u6267\u884c \uff08\u4e5f\u5c31\u662f\u6267\u884c\u5b8c\u4e00\u4e2a\u518d\u6267\u884c\u53e6\u4e00\u4e2a\uff09\u7684\u60c5\u51b5\u4e0b\u53ef\u80fd\u4f1a\u51fa\u73b0\u54ea\u4e9b\u95ee\u9898\uff1a\r\n\r\n# 1. \u810f\u5199\uff08 Dirty Write \uff09\r\n# \u5bf9\u4e8e\u4e24\u4e2a\u4e8b\u52a1 Session A\u3001Session B\uff0c\u5982\u679c\u4e8b\u52a1Session A \u4fee\u6539\u4e86 \u53e6\u4e00\u4e2a \u672a\u63d0\u4ea4 \u4e8b\u52a1Session B \u4fee\u6539\u8fc7 \u7684\u6570\u636e\uff0c\r\n# \u90a3\u5c31\u610f\u5473\u7740\u53d1\u751f\u4e86 \u810f\u5199\r\n\r\n# 2. \u810f\u8bfb\uff08 Dirty Read \uff09\r\n# \u5bf9\u4e8e\u4e24\u4e2a\u4e8b\u52a1 Session A\u3001Session B\uff0cSession A \u8bfb\u53d6 \u4e86\u5df2\u7ecf\u88ab Session B \u66f4\u65b0 \u4f46\u8fd8 \u6ca1\u6709\u88ab\u63d0\u4ea4 \u7684\u5b57\u6bb5\u3002\r\n# \u4e4b\u540e\u82e5 Session B \u56de\u6eda \uff0cSession A \u8bfb\u53d6 \u7684\u5185\u5bb9\u5c31\u662f \u4e34\u65f6\u4e14\u65e0\u6548 \u7684\u3002\r\n\r\n# Session A\u548cSession B\u5404\u5f00\u542f\u4e86\u4e00\u4e2a\u4e8b\u52a1\uff0cSession B\u4e2d\u7684\u4e8b\u52a1\u5148\u5c06studentno\u5217\u4e3a1\u7684\u8bb0\u5f55\u7684name\u5217\u66f4\u65b0\u4e3a'\u5f20\u4e09'\uff0c\r\n# \u7136\u540eSession A\u4e2d\u7684\u4e8b\u52a1\u518d\u53bb\u67e5\u8be2\u8fd9\u6761studentno\u4e3a1\u7684\u8bb0\u5f55\uff0c\u5982\u679c\u8bfb\u5230\u5217name\u7684\u503c\u4e3a'\u5f20\u4e09'\uff0c\r\n# \u800cSession B\u4e2d\u7684\u4e8b\u52a1\u7a0d\u540e\u8fdb\u884c\u4e86\u56de\u6eda\uff0c\u90a3\u4e48Session A\u4e2d\u7684\u4e8b\u52a1\u76f8\u5f53\u4e8e\u8bfb\u5230\u4e86\u4e00\u4e2a\u4e0d\u5b58\u5728\u7684\u6570\u636e\uff0c\r\n# \u8fd9\u79cd\u73b0\u8c61\u5c31\u79f0\u4e4b\u4e3a \u810f\u8bfb \u3002\r\n\r\n# 3. \u4e0d\u53ef\u91cd\u590d\u8bfb\uff08 Non-Repeatable Read \uff09\r\n# \u5bf9\u4e8e\u4e24\u4e2a\u4e8b\u52a1Session A\u3001Session B\uff0cSession A \u8bfb\u53d6 \u4e86\u4e00\u4e2a\u5b57\u6bb5\uff0c\u7136\u540e Session B \u66f4\u65b0 \u4e86\u8be5\u5b57\u6bb5\u3002\r\n# \u4e4b\u540eSession A \u518d\u6b21\u8bfb\u53d6 \u540c\u4e00\u4e2a\u5b57\u6bb5\uff0c \u503c\u5c31\u4e0d\u540c \u4e86\u3002\u90a3\u5c31\u610f\u5473\u7740\u53d1\u751f\u4e86\u4e0d\u53ef\u91cd\u590d\u8bfb\u3002\r\n\r\n# \u6211\u4eec\u5728Session B\u4e2d\u63d0\u4ea4\u4e86\u51e0\u4e2a \u9690\u5f0f\u4e8b\u52a1 \uff08\u6ce8\u610f\u662f\u9690\u5f0f\u4e8b\u52a1\uff0c\u610f\u5473\u7740\u8bed\u53e5\u7ed3\u675f\u4e8b\u52a1\u5c31\u63d0\u4ea4\u4e86\uff09\uff0c\r\n# \u8fd9\u4e9b\u4e8b\u52a1\u90fd\u4fee\u6539\u4e86studentno\u5217\u4e3a1\u7684\u8bb0\u5f55\u7684\u5217name\u7684\u503c\uff0c\u6bcf\u6b21\u4e8b\u52a1\u63d0\u4ea4\u4e4b\u540e\uff0c\r\n# \u5982\u679cSession A\u4e2d\u7684\u4e8b\u52a1\u90fd\u53ef\u4ee5\u67e5\u770b\u5230\u6700\u65b0\u7684\u503c\uff0c\u8fd9\u79cd\u73b0\u8c61\u4e5f\u88ab\u79f0\u4e4b\u4e3a \u4e0d\u53ef\u91cd\u590d\u8bfb \u3002\r\n\r\n# 4. \u5e7b\u8bfb\uff08 Phantom \uff09\r\n# \u5bf9\u4e8e\u4e24\u4e2a\u4e8b\u52a1Session A\u3001Session B, Session A \u4ece\u4e00\u4e2a\u8868\u4e2d \u8bfb\u53d6 \u4e86\u4e00\u4e2a\u5b57\u6bb5,\r\n# \u7136\u540e Session B \u5728\u8be5\u8868\u4e2d \u63d2\u5165 \u4e86\u4e00\u4e9b\u65b0\u7684\u884c\u3002 \u4e4b\u540e, \u5982\u679c Session A \u518d\u6b21\u8bfb\u53d6 \u540c\u4e00\u4e2a\u8868, \u5c31\u4f1a\u591a\u51fa\u51e0\u884c\u3002\r\n# \u90a3\u5c31\u610f\u5473\u7740\u53d1\u751f\u4e86\u5e7b\u8bfb\u3002\r\n\r\n# Session A\u4e2d\u7684\u4e8b\u52a1\u5148\u6839\u636e\u6761\u4ef6 studentno > 0\u8fd9\u4e2a\u6761\u4ef6\u67e5\u8be2\u8868student\uff0c\u5f97\u5230\u4e86name\u5217\u503c\u4e3a'\u5f20\u4e09'\u7684\u8bb0\u5f55\uff1b\r\n# \u4e4b\u540eSession B\u4e2d\u63d0\u4ea4\u4e86\u4e00\u4e2a \u9690\u5f0f\u4e8b\u52a1 \uff0c\u8be5\u4e8b\u52a1\u5411\u8868student\u4e2d\u63d2\u5165\u4e86\u4e00\u6761\u65b0\u8bb0\u5f55\uff1b\r\n# \u4e4b\u540eSession A\u4e2d\u7684\u4e8b\u52a1\u518d\u6839\u636e\u76f8\u540c\u7684\u6761\u4ef6 studentno > 0\u67e5\u8be2\u8868student\uff0c\r\n# \u5f97\u5230\u7684\u7ed3\u679c\u96c6\u4e2d\u5305\u542bSession B\u4e2d\u7684\u4e8b\u52a1\u65b0\u63d2\u5165\u7684\u90a3\u6761\u8bb0\u5f55\uff0c\u8fd9\u79cd\u73b0\u8c61\u4e5f\u88ab\u79f0\u4e4b\u4e3a \u5e7b\u8bfb \u3002\r\n# \u6211\u4eec\u628a\u65b0\u63d2\u5165\u7684\u90a3\u4e9b\u8bb0\u5f55\u79f0\u4e4b\u4e3a \u5e7b\u5f71\u8bb0\u5f55 \u3002\r\n\r\n# 3.3 SQL\u4e2d\u7684\u56db\u79cd\u9694\u79bb\u7ea7\u522b\r\n\r\n# \u4e0a\u9762\u4ecb\u7ecd\u4e86\u51e0\u79cd\u5e76\u53d1\u4e8b\u52a1\u6267\u884c\u8fc7\u7a0b\u4e2d\u53ef\u80fd\u9047\u5230\u7684\u4e00\u4e9b\u95ee\u9898\uff0c\u8fd9\u4e9b\u95ee\u9898\u6709\u8f7b\u91cd\u7f13\u6025\u4e4b\u5206\uff0c\r\n# \u6211\u4eec\u7ed9\u8fd9\u4e9b\u95ee\u9898\u6309\u7167\u4e25\u91cd\u6027\u6765\u6392\u4e00\u4e0b\u5e8f\uff1a\r\n\r\n# \u810f\u5199 > \u810f\u8bfb > \u4e0d\u53ef\u91cd\u590d\u8bfb > \u5e7b\u8bfb\r\n\r\n# \u6211\u4eec\u613f\u610f\u820d\u5f03\u4e00\u90e8\u5206\u9694\u79bb\u6027\u6765\u6362\u53d6\u4e00\u90e8\u5206\u6027\u80fd\u5728\u8fd9\u91cc\u5c31\u4f53\u73b0\u5728\uff1a\u8bbe\u7acb\u4e00\u4e9b\u9694\u79bb\u7ea7\u522b\uff0c\u9694\u79bb\u7ea7\u522b\u8d8a\u4f4e\uff0c\r\n# \u5e76\u53d1\u95ee\u9898\u53d1\u751f\u7684\u5c31\u8d8a\u591a\u3002 SQL\u6807\u51c6 \u4e2d\u8bbe\u7acb\u4e864\u4e2a \u9694\u79bb\u7ea7\u522b \uff1a\r\n\r\n# READ UNCOMMITTED \uff1a\u8bfb\u672a\u63d0\u4ea4\uff0c\u5728\u8be5\u9694\u79bb\u7ea7\u522b\uff0c\u6240\u6709\u4e8b\u52a1\u90fd\u53ef\u4ee5\u770b\u5230\u5176\u4ed6\u672a\u63d0\u4ea4\u4e8b\u52a1\u7684\u6267\u884c\u7ed3\u679c\u3002\r\n# \u4e0d\u80fd\u907f\u514d\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb\u3001\u5e7b\u8bfb\u3002\r\n\r\n# READ COMMITTED \uff1a\u8bfb\u5df2\u63d0\u4ea4\uff0c\u5b83\u6ee1\u8db3\u4e86\u9694\u79bb\u7684\u7b80\u5355\u5b9a\u4e49\uff1a\u4e00\u4e2a\u4e8b\u52a1\u53ea\u80fd\u770b\u89c1\u5df2\u7ecf\u63d0\u4ea4\u4e8b\u52a1\u6240\u505a\u7684\u6539\u53d8\u3002\r\n# \u8fd9\u662f\u5927\u591a\u6570\u6570\u636e\u5e93\u7cfb\u7edf\u7684\u9ed8\u8ba4\u9694\u79bb\u7ea7\u522b\uff08\u4f46\u4e0d\u662fMySQL\u9ed8\u8ba4\u7684\uff09\u3002\u53ef\u4ee5\u907f\u514d\u810f\u8bfb\uff0c\u4f46\u4e0d\u53ef\u91cd\u590d\u8bfb\u3001\u5e7b\u8bfb\u95ee\u9898\u4ecd\u7136\u5b58\u5728\u3002\r\n\r\n# REPEATABLE READ \uff1a\u53ef\u91cd\u590d\u8bfb\uff0c\u4e8b\u52a1A\u5728\u8bfb\u5230\u4e00\u6761\u6570\u636e\u4e4b\u540e\uff0c\u6b64\u65f6\u4e8b\u52a1B\u5bf9\u8be5\u6570\u636e\u8fdb\u884c\u4e86\u4fee\u6539\u5e76\u63d0\u4ea4\uff0c\r\n# \u90a3\u4e48\u4e8b\u52a1A\u518d\u8bfb\u8be5\u6570\u636e\uff0c\u8bfb\u5230\u7684\u8fd8\u662f\u539f\u6765\u7684\u5185\u5bb9\u3002\u53ef\u4ee5\u907f\u514d\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb\uff0c\u4f46\u5e7b\u8bfb\u95ee\u9898\u4ecd\u7136\u5b58\u5728\u3002\r\n# \u8fd9\u662fMySQL\u7684\u9ed8\u8ba4\u9694\u79bb\u7ea7\u522b\u3002\r\n\r\n# SERIALIZABLE \uff1a\u53ef\u4e32\u884c\u5316\uff0c\u786e\u4fdd\u4e8b\u52a1\u53ef\u4ee5\u4ece\u4e00\u4e2a\u8868\u4e2d\u8bfb\u53d6\u76f8\u540c\u7684\u884c\u3002\u5728\u8fd9\u4e2a\u4e8b\u52a1\u6301\u7eed\u671f\u95f4\uff0c\r\n# \u7981\u6b62\u5176\u4ed6\u4e8b\u52a1\u5bf9\u8be5\u8868\u6267\u884c\u63d2\u5165\u3001\u66f4\u65b0\u548c\u5220\u9664\u64cd\u4f5c\u3002\u6240\u6709\u7684\u5e76\u53d1\u95ee\u9898\u90fd\u53ef\u4ee5\u907f\u514d\uff0c\u4f46\u6027\u80fd\u5341\u5206\u4f4e\u4e0b\u3002\r\n# \u80fd\u907f\u514d\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb\u548c\u5e7b\u8bfb\u3002\r\n\r\n# \u810f\u5199 \u600e\u4e48\u6ca1\u6d89\u53ca\u5230\uff1f\u56e0\u4e3a\u810f\u5199\u8fd9\u4e2a\u95ee\u9898\u592a\u4e25\u91cd\u4e86\uff0c\u4e0d\u8bba\u662f\u54ea\u79cd\u9694\u79bb\u7ea7\u522b\uff0c\u90fd\u4e0d\u5141\u8bb8\u810f\u5199\u7684\u60c5\u51b5\u53d1\u751f\u3002\r\n\r\n# \u4e0d\u540c\u7684\u9694\u79bb\u7ea7\u522b\u6709\u4e0d\u540c\u7684\u73b0\u8c61\uff0c\u5e76\u6709\u4e0d\u540c\u7684\u9501\u548c\u5e76\u53d1\u673a\u5236\uff0c\u9694\u79bb\u7ea7\u522b\u8d8a\u9ad8\uff0c\u6570\u636e\u5e93\u7684\u5e76\u53d1\u6027\u80fd\u5c31\u8d8a\u5dee\uff0c\r\n\r\n# 3.4 MySQL\u652f\u6301\u7684\u56db\u79cd\u9694\u79bb\u7ea7\u522b\r\n\r\n# \u67e5\u770b\u9694\u79bb\u7ea7\u522b\uff0cMySQL 5.7.20\u7684\u7248\u672c\u4e4b\u524d\uff1a\r\nSHOW VARIABLES LIKE 'tx_isolation';\r\n\r\n# MySQL 5.7.20\u7248\u672c\u4e4b\u540e\uff0c\u5f15\u5165transaction_isolation\u6765\u66ff\u6362tx_isolation\r\n# \u67e5\u770b\u9694\u79bb\u7ea7\u522b\uff0cMySQL 5.7.20\u7684\u7248\u672c\u53ca\u4e4b\u540e\uff1a\r\nSHOW VARIABLES LIKE 'transaction_isolation';\r\n\r\n#\u6216\u8005\u4e0d\u540cMySQL\u7248\u672c\u4e2d\u90fd\u53ef\u4ee5\u4f7f\u7528\u7684\uff1a\r\nSELECT @@transaction_isolation;\r\n\r\n# 3.5 \u5982\u4f55\u8bbe\u7f6e\u4e8b\u52a1\u7684\u9694\u79bb\u7ea7\u522b\r\n\r\n# \u901a\u8fc7\u4e0b\u9762\u7684\u8bed\u53e5\u4fee\u6539\u4e8b\u52a1\u7684\u9694\u79bb\u7ea7\u522b\uff1a\r\n# SET &#91;GLOBAL|SESSION] TRANSACTION ISOLATION LEVEL \u9694\u79bb\u7ea7\u522b;\r\n#\u5176\u4e2d\uff0c\u9694\u79bb\u7ea7\u522b\u683c\u5f0f\uff1a\r\n# > READ UNCOMMITTED\r\n# > READ COMMITTED\r\n# > REPEATABLE READ\r\n# > SERIALIZABLE\r\n\r\n# \u6216\u8005\uff1a\r\n\r\n# SET &#91;GLOBAL|SESSION] TRANSACTION_ISOLATION = '\u9694\u79bb\u7ea7\u522b'\r\n#\u5176\u4e2d\uff0c\u9694\u79bb\u7ea7\u522b\u683c\u5f0f\uff1a\r\n# > READ-UNCOMMITTED\r\n# > READ-COMMITTED\r\n# > REPEATABLE-READ\r\n# > SERIALIZABLE\r\n\r\n# \u5173\u4e8e\u8bbe\u7f6e\u65f6\u4f7f\u7528GLOBAL\u6216SESSION\u7684\u5f71\u54cd\uff1a\r\n\r\n# \u4f7f\u7528 GLOBAL \u5173\u952e\u5b57\uff08\u5728\u5168\u5c40\u8303\u56f4\u5f71\u54cd\uff09\uff1a\r\n#     SET GLOBAL TRANSACTION ISOLATION LEVEL SERIALIZABLE;\r\n#     \u6216\r\n#     SET GLOBAL TRANSACTION ISOLATION = 'SERIALIZABLE';\r\n# \u5219\uff1a\r\n#     \u5f53\u524d\u5df2\u7ecf\u5b58\u5728\u7684\u4f1a\u8bdd\u65e0\u6548\r\n#     \u53ea\u5bf9\u6267\u884c\u5b8c\u8be5\u8bed\u53e5\u4e4b\u540e\u4ea7\u751f\u7684\u4f1a\u8bdd\u8d77\u4f5c\u7528\r\n\r\n# \u4f7f\u7528 SESSION \u5173\u952e\u5b57\uff08\u5728\u4f1a\u8bdd\u8303\u56f4\u5f71\u54cd\uff09\uff1a\r\n#     SET SESSION TRANSACTION ISOLATION LEVEL SERIALIZABLE;\r\n#     \u6216\r\n#     SET SESSION TRANSACTION_ISOLATION = 'SERIALIZABLE';\r\n# \u5219\uff1a\r\n#     \u5bf9\u5f53\u524d\u4f1a\u8bdd\u7684\u6240\u6709\u540e\u7eed\u7684\u4e8b\u52a1\u6709\u6548\r\n#     \u5982\u679c\u5728\u4e8b\u52a1\u4e4b\u95f4\u6267\u884c\uff0c\u5219\u5bf9\u540e\u7eed\u7684\u4e8b\u52a1\u6709\u6548\r\n#     \u8be5\u8bed\u53e5\u53ef\u4ee5\u5728\u5df2\u7ecf\u5f00\u542f\u7684\u4e8b\u52a1\u4e2d\u95f4\u6267\u884c\uff0c\u4f46\u4e0d\u4f1a\u5f71\u54cd\u5f53\u524d\u6b63\u5728\u6267\u884c\u7684\u4e8b\u52a1\r\n\r\n# \u5c0f\u7ed3\uff1a\r\n# \u6570\u636e\u5e93\u89c4\u5b9a\u4e86\u591a\u79cd\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff0c\u4e0d\u540c\u9694\u79bb\u7ea7\u522b\u5bf9\u5e94\u4e0d\u540c\u7684\u5e72\u6270\u7a0b\u5ea6\uff0c\u9694\u79bb\u7ea7\u522b\u8d8a\u9ad8\uff0c\r\n# \u6570\u636e\u4e00\u81f4\u6027\u5c31\u8d8a\u597d\uff0c\u4f46\u5e76\u53d1\u6027\u8d8a\u5f31\u3002\r\n\r\nSET GLOBAL transaction_isolation = 'read-committed';\r\n\r\nSELECT @@transaction_isolation;\r\n\r\nSET SESSION transaction_isolation = 'read-uncommitted';\r\n\r\nSELECT @@transaction_isolation;\r\n\r\n# 3.6 \u4e0d\u540c\u9694\u79bb\u7ea7\u522b\u4e3e\u4f8b\r\n\r\n# \u6f14\u793a1. \u810f\u8bfb\r\n\r\n#\u4e8b\u52a11\uff1a\r\n\r\nUSE atguigudb3;\r\n\r\nSHOW TABLES;\r\n\r\nCREATE TABLE account(\r\n    id INT PRIMARY KEY AUTO_INCREMENT,\r\n    name VARCHAR(15),\r\n    balance DECIMAL(10,2)\r\n);\r\n\r\nINSERT INTO account\r\nVALUES (1,'\u5f20\u4e09','100'),\r\n       (2,'\u674e\u56db',0);\r\n\r\nSELECT * FROM account;\r\n\r\nSELECT @@transaction_isolation;\r\n\r\nSET SESSION transaction_isolation = 'read-uncommitted';\r\n\r\nSELECT @@transaction_isolation;\r\n\r\nSELECT * FROM account;\r\n\r\nBEGIN;\r\n\r\nUPDATE account SET balance = balance + 100\r\nWHERE id = 1;\r\n\r\nROLLBACK;\r\n\r\nSELECT * FROM account;\r\n\r\nBEGIN;\r\n\r\nUPDATE account SET balance = balance - 100\r\nWHERE id = 1;\r\n\r\nUPDATE account SET balance = balance + 100\r\nWHERE id = 2;\r\n\r\nSELECT * FROM account;\r\n\r\nROLLBACK;\r\n\r\nSELECT * FROM account;\r\n\r\n# \u6f14\u793a2. \u4e0d\u53ef\u91cd\u590d\u8bfb\r\n\r\nTRUNCATE TABLE account;\r\n\r\nINSERT INTO account\r\nVALUES (1,'\u5f20\u4e09','100'),\r\n       (2,'\u674e\u56db',0);\r\n\r\nSELECT * FROM account;\r\n\r\nSET SESSION transaction_isolation = 'read-committed';\r\n\r\nBEGIN;\r\n\r\nUPDATE account SET balance = balance - 50\r\nWHERE id = 1;\r\n\r\nSELECT * FROM account;\r\n\r\nCOMMIT;\r\n\r\nSELECT * FROM account;\r\n\r\n\r\n#\u6f14\u793a3. \u53ef\u91cd\u590d\u8bfb\r\n\r\nSET SESSION transaction_isolation = 'repeatable-read';\r\n\r\nSELECT @@transaction_isolation;\r\n\r\nBEGIN;\r\n\r\nSELECT * FROM account;\r\n\r\nUPDATE account SET balance = balance - 10\r\nWHERE id = 1;\r\n\r\nSELECT * FROM account;\r\n\r\nCOMMIT;\r\n\r\n#\u6f14\u793a4. \u5e7b\u8bfb\r\n\r\nSELECT @@transaction_isolation;\r\n\r\nBEGIN;\r\n\r\nINSERT INTO account(id, name, balance)\r\nVALUES(3,'\u738b\u4e94',100);\r\n\r\nSELECT * FROM account;\r\n\r\nCOMMIT;\r\n\r\n# 4. \u4e8b\u52a1\u7684\u5e38\u89c1\u5206\u7c7b\r\n\r\n# \u4ece\u4e8b\u52a1\u7406\u8bba\u7684\u89d2\u5ea6\u6765\u770b\uff0c\u53ef\u4ee5\u628a\u4e8b\u52a1\u5206\u4e3a\u4ee5\u4e0b\u51e0\u79cd\u7c7b\u578b\uff1a\r\n# \u6241\u5e73\u4e8b\u52a1\uff08Flat Transactions\uff09\r\n# \u5e26\u6709\u4fdd\u5b58\u70b9\u7684\u6241\u5e73\u4e8b\u52a1\uff08Flat Transactions with Savepoints\uff09\r\n# \u94fe\u4e8b\u52a1\uff08Chained Transactions\uff09\r\n# \u5d4c\u5957\u4e8b\u52a1\uff08Nested Transactions\uff09\r\n# \u5206\u5e03\u5f0f\u4e8b\u52a1\uff08Distributed Transactions\uff09\r\n\r\n\r\n<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code># \u7b2c13\u7ae0_\u4e8b\u52a1\u57fa\u7840\u77e5\u8bc6\r\n\r\n# 3.6 \u4e0d\u540c\u9694\u79bb\u7ea7\u522b\u4e3e\u4f8b\r\n\r\n# \u6f14\u793a1. \u810f\u8bfb\r\n\r\n#\u4e8b\u52a12\uff1a\r\n\r\nuse atguigudb3;\r\n\r\nselect @@transaction_isolation;\r\n\r\nset session transaction_isolation = 'read-uncommitted';\r\n\r\nselect @@transaction_isolation;\r\n\r\nselect * from account;\r\n\r\nselect * from account;\r\n\r\nbegin;\r\n\r\nselect * from account;\r\n\r\nupdate account set balance = balance - 100 where id = 2;\r\n\r\nupdate account set balance = balance + 100 where id = 1;\r\n\r\ncommit;\r\n\r\nselect * from account;\r\n\r\n# \u6f14\u793a2. \u4e0d\u53ef\u91cd\u590d\u8bfb\r\n\r\nselect * from account;\r\n\r\nSET SESSION transaction_isolation = 'read-committed';\r\n\r\nbegin;\r\n\r\nselect * from account;\r\n\r\nselect * from account;\r\n\r\nselect * from account;\r\n\r\ncommit;\r\n\r\nselect * from account;\r\n\r\n#\u6f14\u793a3. \u53ef\u91cd\u590d\u8bfb\r\n\r\nSET SESSION transaction_isolation = 'repeatable-read';\r\n\r\nselect @@transaction_isolation;\r\n\r\nselect * from account;\r\n\r\nbegin;\r\n\r\nselect * from account;\r\n\r\nselect * from account;\r\n\r\nselect * from account;\r\n\r\ncommit;\r\n\r\nselect * from account;\r\n\r\n#\u6f14\u793a4. \u5e7b\u8bfb\r\n\r\nselect @@transaction_isolation;\r\n\r\nbegin;\r\n\r\nselect count(*) from account where id = 3;\r\n\r\nselect count(*) from account where id = 3;\r\n\r\ninsert into account(id,name,balance) values(3,'\u738b\u4e94',1000);\r\n\r\nrollback;<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[47],"class_list":["post-1678","post","type-post","status-publish","format-standard","hentry","category-mysql-code","tag-mysql"],"_links":{"self":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1678"}],"collection":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1678"}],"version-history":[{"count":1,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1678\/revisions"}],"predecessor-version":[{"id":1679,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1678\/revisions\/1679"}],"wp:attachment":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1678"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1678"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1678"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}