{"id":246,"date":"2023-02-24T06:04:53","date_gmt":"2023-02-23T22:04:53","guid":{"rendered":"https:\/\/www.appblog.cn\/?p=246"},"modified":"2023-04-30T15:19:53","modified_gmt":"2023-04-30T07:19:53","slug":"mysql-sequence-usage","status":"publish","type":"post","link":"https:\/\/www.appblog.cn\/index.php\/2023\/02\/24\/mysql-sequence-usage\/","title":{"rendered":"MySQL \u5e8f\u5217\u4f7f\u7528"},"content":{"rendered":"

MySQL\u5e8f\u5217\u662f\u4e00\u7ec4\u6574\u6570\uff1a1, 2, 3, ...<\/code>\uff0c\u7531\u4e8e\u4e00\u5f20\u6570\u636e\u8868\u53ea\u80fd\u6709\u4e00\u4e2a\u5b57\u6bb5\u81ea\u589e\u4e3b\u952e\uff0c\u5982\u679c\u60f3\u8981\u5176\u4ed6\u5b57\u6bb5\u4e5f\u5b9e\u73b0\u81ea\u52a8\u589e\u52a0\uff0c\u5c31\u53ef\u4ee5\u4f7f\u7528MySQL\u5e8f\u5217\u6765\u5b9e\u73b0\u3002<\/p>\n

\u4f7f\u7528 AUTO_INCREMENT<\/h2>\n

<\/p>\n

MySQL\u4e2d\u6700\u7b80\u5355\u4f7f\u7528\u5e8f\u5217\u7684\u65b9\u6cd5\u5c31\u662f\u4f7f\u7528MySQL AUTO_INCREMENT<\/code>\u6765\u5b9a\u4e49\u5217<\/p>\n

\u4ee5\u4e0b\u5b9e\u4f8b\u4e2d\u521b\u5efa\u6570\u636e\u8868insect<\/code>\uff0cinsect<\/code>\u8868\u4e2did<\/code>\u65e0\u9700\u6307\u5b9a\u503c\u53ef\u5b9e\u73b0\u81ea\u52a8\u589e\u957f<\/p>\n

mysql> CREATE TABLE insect\n    -> (\n    -> id INT UNSIGNED NOT NULL AUTO_INCREMENT,\n    -> PRIMARY KEY (id),\n    -> name VARCHAR(30) NOT NULL, # type of insect\n    -> date DATE NOT NULL, # date collected\n    -> origin VARCHAR(30) NOT NULL # where collected\n);\nQuery OK, 0 rows affected (0.02 sec)\nmysql> INSERT INTO insect (id,name,date,origin) VALUES\n    -> (NULL,'housefly','2001-09-10','kitchen'),\n    -> (NULL,'millipede','2001-09-10','driveway'),\n    -> (NULL,'grasshopper','2001-09-10','front yard');\nQuery OK, 3 rows affected (0.02 sec)\nRecords: 3  Duplicates: 0  Warnings: 0\nmysql> SELECT * FROM insect ORDER BY id;\n+----+-------------+------------+------------+\n| id | name        | date       | origin     |\n+----+-------------+------------+------------+\n|  1 | housefly    | 2001-09-10 | kitchen    |\n|  2 | millipede   | 2001-09-10 | driveway   |\n|  3 | grasshopper | 2001-09-10 | front yard |\n+----+-------------+------------+------------+\n3 rows in set (0.00 sec)<\/code><\/pre>\n
\u83b7\u53d6AUTO_INCREMENT\u503c<\/h2>\n
\u5728MySQL\u5ba2\u6237\u7aef\u4e2d\u53ef\u4ee5\u4f7f\u7528SQL\u4e2d\u7684LAST_INSERT_ID()<\/code>\u51fd\u6570\u6765\u83b7\u53d6\u6700\u540e\u7684\u63d2\u5165\u8868\u4e2d\u7684\u81ea\u589e\u5217\u7684\u503c<\/p>\n
\u5728PHP\u811a\u672c\u4e2d\u4e5f\u63d0\u4f9b\u4e86\u76f8\u5e94\u7684\u51fd\u6570\u6765\u83b7\u53d6\u6700\u540e\u7684\u63d2\u5165\u8868\u4e2d\u7684\u81ea\u589e\u5217\u7684\u503c<\/p>\n
PHP\u901a\u8fc7mysql_insert_id()<\/code>\u51fd\u6570\u6765\u83b7\u53d6\u6267\u884c\u7684\u63d2\u5165SQL\u8bed\u53e5\u4e2dAUTO_INCREMENT<\/code>\u5217\u7684\u503c\uff1a<\/p>\n
mysql_query("INSERT INTO insect (name,date,origin) VALUES('moth','2001-09-14','windowsill')", $conn_id);\n$seq = mysql_insert_id ($conn_id);<\/code><\/pre>\n
\u91cd\u7f6e\u5e8f\u5217<\/h2>\n
\u5982\u679c\u5220\u9664\u4e86\u6570\u636e\u8868\u4e2d\u7684\u591a\u6761\u8bb0\u5f55\uff0c\u5e76\u5e0c\u671b\u5bf9\u5269\u4e0b\u6570\u636e\u7684AUTO_INCREMENT<\/code>\u5217\u8fdb\u884c\u91cd\u65b0\u6392\u5217\uff0c\u90a3\u4e48\u53ef\u4ee5\u901a\u8fc7\u5220\u9664\u81ea\u589e\u7684\u5217\uff0c\u7136\u540e\u91cd\u65b0\u6dfb\u52a0\u6765\u5b9e\u73b0\u3002\u4e0d\u8fc7\u8be5\u64cd\u4f5c\u8981\u975e\u5e38\u5c0f\u5fc3\uff0c\u5982\u679c\u5728\u5220\u9664\u7684\u540c\u65f6\u53c8\u6709\u65b0\u8bb0\u5f55\u6dfb\u52a0\uff0c\u6709\u53ef\u80fd\u4f1a\u51fa\u73b0\u6570\u636e\u6df7\u4e71\u3002\u64cd\u4f5c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
mysql> ALTER TABLE insect DROP id;\nmysql> ALTER TABLE insect\n    -> ADD id INT UNSIGNED NOT NULL AUTO_INCREMENT FIRST,\n    -> ADD PRIMARY KEY (id);<\/code><\/pre>\n
\u8bbe\u7f6e\u5e8f\u5217\u7684\u5f00\u59cb\u503c<\/h2>\n
\u4e00\u822c\u60c5\u51b5\u4e0b\u5e8f\u5217\u7684\u5f00\u59cb\u503c\u4e3a1\uff0c\u4f46\u5982\u679c\u9700\u8981\u6307\u5b9a\u4e00\u4e2a\u5f00\u59cb\u503c100\uff0c\u90a3\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u8bed\u53e5\u6765\u5b9e\u73b0\uff1a<\/p>\n
mysql> CREATE TABLE insect\n    -> (\n    -> id INT UNSIGNED NOT NULL AUTO_INCREMENT,\n    -> PRIMARY KEY (id),\n    -> name VARCHAR(30) NOT NULL, \n    -> date DATE NOT NULL,\n    -> origin VARCHAR(30) NOT NULL\n)engine=innodb auto_increment=100 charset=utf8;<\/code><\/pre>\n
\u6216\u8005\u4e5f\u53ef\u4ee5\u5728\u8868\u521b\u5efa\u6210\u529f\u540e\uff0c\u901a\u8fc7\u4ee5\u4e0b\u8bed\u53e5\u6765\u5b9e\u73b0\uff1a<\/p>\n
mysql> ALTER TABLE t AUTO_INCREMENT = 100;<\/code><\/pre>\n
\u81ea\u589e\u5e8f\u5217\u7ba1\u7406\u8868<\/h2>\n
\u4f7f\u7528\u51fd\u6570\u521b\u5efa\u81ea\u589e\u5e8f\u5217\u7ba1\u7406\u8868(\u6279\u91cf\u4f7f\u7528\u81ea\u589e\u8868,\u8bbe\u7f6e\u521d\u59cb\u503c,\u81ea\u589e\u5e45\u5ea6)<\/p>\n
\uff081\uff09\u521b\u5efaSequence\u7ba1\u7406\u8868sequence<\/p>\n
DROP TABLE IF EXISTS sequence; \nCREATE TABLE sequence ( \n  name VARCHAR(50) NOT NULL, \n  current_value INT NOT NULL, \n  increment INT NOT NULL DEFAULT 1, \n  PRIMARY KEY (name) \n) ENGINE=InnoDB;<\/code><\/pre>\n
\uff082\uff09\u521b\u5efa\u53d6\u5f53\u524d\u503c\u7684\u51fd\u6570currval<\/p>\n
DROP FUNCTION IF EXISTS currval; \nDELIMITER $ \nCREATE FUNCTION currval (seq_name VARCHAR(50)) \nRETURNS INTEGER\nLANGUAGE SQL \nDETERMINISTIC \nCONTAINS SQL \nSQL SECURITY DEFINER \nCOMMENT ''\nBEGIN\nDECLARE value INTEGER; \nSET value = 0; \nSELECT current_value INTO value \nFROM sequence\nWHERE name = seq_name; \nRETURN value; \nEND\n$ \nDELIMITER ;<\/code><\/pre>\n
\uff083\uff09\u521b\u5efa\u53d6\u4e0b\u4e00\u4e2a\u503c\u7684\u51fd\u6570 nextval<\/p>\n
DROP FUNCTION IF EXISTS nextval; \nDELIMITER $ \nCREATE FUNCTION nextval (seq_name VARCHAR(50)) \nRETURNS INTEGER\nLANGUAGE SQL \nDETERMINISTIC \nCONTAINS SQL \nSQL SECURITY DEFINER \nCOMMENT ''\nBEGIN\nUPDATE sequence\nSET current_value = current_value + increment \nWHERE name = seq_name; \nRETURN currval(seq_name); \nEND\n$ \nDELIMITER;<\/code><\/pre>\n
\uff084\uff09\u521b\u5efa\u66f4\u65b0\u5f53\u524d\u503c\u7684\u51fd\u6570setval<\/p>\n
DROP FUNCTION IF EXISTS setval; \nDELIMITER $ \nCREATE FUNCTION setval (seq_name VARCHAR(50), value INTEGER) \nRETURNS INTEGER\nLANGUAGE SQL \nDETERMINISTIC \nCONTAINS SQL \nSQL SECURITY DEFINER \nCOMMENT ''\nBEGIN\nUPDATE sequence\nSET current_value = value \nWHERE name = seq_name; \nRETURN currval(seq_name); \nEND\n$ \nDELIMITER ;<\/code><\/pre>\n
\uff085\uff09\u6d4b\u8bd5\u51fd\u6570\u529f\u80fd<\/p>\n
\u5f53\u4e0a\u8ff0\u56db\u6b65\u5b8c\u6210\u540e\uff0c\u53ef\u4ee5\u7528\u4ee5\u4e0b\u6570\u636e\u8bbe\u7f6e\u9700\u8981\u521b\u5efa\u7684sequence\u540d\u79f0\u4ee5\u53ca\u8bbe\u7f6e\u521d\u59cb\u503c\u548c\u83b7\u53d6\u5f53\u524d\u503c\u548c\u4e0b\u4e00\u4e2a\u503c\u3002<\/p>\n
--\u6dfb\u52a0\u4e00\u4e2asequence\u540d\u79f0\u548c\u521d\u59cb\u503c\uff0c\u4ee5\u53ca\u81ea\u589e\u5e45\u5ea6\uff1a\u6dfb\u52a0\u4e00\u4e2a\u540d\u4e3aTestSeq\u7684\u81ea\u589e\u5e8f\u5217\nINSERT INTO sequence VALUES ('TestSeq', 0, 1);\n\n--\u8bbe\u7f6e\u6307\u5b9asequence\u7684\u521d\u59cb\u503c\uff0c\u8fd9\u91cc\u8bbe\u7f6eTestSeq \u7684\u521d\u59cb\u503c\u4e3a10\nSELECT SETVAL('TestSeq', 10);\n\n--\u67e5\u8be2\u6307\u5b9asequence\u7684\u5f53\u524d\u503c\uff0c\u8fd9\u91cc\u662f\u83b7\u53d6TestSeq\u5f53\u524d\u503c\nSELECT CURRVAL('TestSeq');\n\n--\u67e5\u8be2\u6307\u5b9asequence\u7684\u4e0b\u4e00\u4e2a\u503c\uff0c\u8fd9\u91cc\u662f\u83b7\u53d6TestSeq\u4e0b\u4e00\u4e2a\u503c\nSELECT NEXTVAL('TestSeq');<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
MySQL\u5e8f\u5217\u662f\u4e00\u7ec4\u6574\u6570\uff1a1, 2, 3, …\uff0c\u7531\u4e8e\u4e00\u5f20\u6570\u636e\u8868\u53ea\u80fd\u6709\u4e00\u4e2a\u5b57\u6bb5\u81ea\u589e\u4e3b\u952e\uff0c\u5982\u679c\u60f3\u8981\u5176\u4ed6\u5b57\u6bb5\u4e5f\u5b9e […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[],"class_list":["post-246","post","type-post","status-publish","format-standard","hentry","category-mysql"],"_links":{"self":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/246","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/comments?post=246"}],"version-history":[{"count":0,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/246\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/media?parent=246"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/categories?post=246"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/tags?post=246"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}