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小編給大家分享一下MySql手動獲取自增主鍵的方法,相信大部分人都還不怎么了解,因此分享這篇文章給大家參考一下,希望大家閱讀完這篇文章后大有收獲,下面讓我們一起去了解一下吧!
mysql手動獲取自增主鍵的方法:通過創(chuàng)建存儲過程外加函數(shù)的方式維護(hù)一張sequences表來獲取數(shù)據(jù),代碼為【last_number = last_number + increment_by】。
mysql手動獲取自增主鍵的方法:
通過創(chuàng)建存儲過程外加函數(shù)的方式維護(hù)一張sequences表來獲取數(shù)據(jù)(一次解決終身受用)。
可以指定每次自增的大小,以及初始數(shù)。
select nextval('TESTDATA') AS batchId CREATE DEFINER=`admin`@`%` FUNCTION `nextval`(seq_name VARCHAR (50)) RETURNS bigint(20) BEGIN UPDATE SEQUENCES SET last_number = last_number + increment_by WHERE sequence_name = seq_name; RETURN currval (seq_name); END;
CREATE DEFINER=`admin`@`%` FUNCTION `currval`(seq_name VARCHAR (50)) RETURNS bigint(20) NO SQL BEGIN SELECT last_number INTO @VALUE FROM SEQUENCES WHERE sequence_name = seq_name; RETURN @VALUE; END;
DROP TABLE IF EXISTS `sequences`; CREATE TABLE `sequences` ( `sequence_owner` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL, `sequence_name` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL, `min_value` bigint(20) NULL DEFAULT 1, `max_value` bigint(20) NULL DEFAULT NULL, `increment_by` bigint(20) NOT NULL DEFAULT 1, `cycle_flag` varchar(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NULL DEFAULT NULL, `order_flag` varchar(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NULL DEFAULT NULL, `cache_size` bigint(20) NOT NULL, `last_number` bigint(20) NOT NULL, PRIMARY KEY (`sequence_name`) USING BTREE, UNIQUE INDEX `sel`(`sequence_owner`, `sequence_name`) USING BTREE ) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_bin ROW_FORMAT = Compact; -- ---------------------------- -- Records of sequences -- ---------------------------- INSERT INTO `sequences` VALUES ('SCM', 'TESTDATA', 1, 9999999999, 1, 'N', 'Y', 20, 0); INSERT INTO `sequences` VALUES ('SCM', 'SEQ', 1, 9999999999, 1, 'N', 'N', 20, 0); SET FOREIGN_KEY_CHECKS = 1;
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