Use mysql to generate unique serial numbers

When the database is divided into tables or the program itself needs a unique ID, we need a solution to generate a unique ID.

You can write a program that combines time and certain characteristics to generate a unique ID. You can also consider using the feature of auto-incrementing IDs in the database to achieve this requirement. Here is an example of mysql.

First create a table that specifically generates ids, where the id field is the primary key and the replace_key field is the unique key.

CREATE TABLE `ticket` (
    `id` bigint(20) unsigned NOT NULL auto_increment,
    `replace_key` char(1) NOT NULL default '',
    PRIMARY KEY (`id`),
    UNIQUE KEY `replace_key` (`replace_key`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=10001;

Every time you need to generate an id, use the replace into statement to generate a new record, replace the old record, and then return the id.

REPLACE INTO `ticket` (`replace_key`) VALUES ('a');
SELECT LAST_INSERT_ID();

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