Missing support for AUTO_INCREMENT columns in multiple-column index for InnoDB tables is a widely known limitation, as is the trigger workaround for when it is needed (see e.g this post [1]). Yesterday, however, I ran into this thread[2] claiming support for this feature was added as early as 5.1. I tried the following statement on my 5.7 install (mysql-community-server-5.7.19-1.el7.x86_64), and it appears to work flawlessly:
CREATE TABLE `tbl1` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`data` datetime NOT NULL,
PRIMARY KEY (`id`,`data`)
) ENGINE=InnoDB;
My problem is that, for the life of me, I cannot find a positive statement of support of the feature on MySQL's documentation site - or elsewhere.
the manual contains, in parts unrelated, this rather oblique statement [3]:
“…an InnoDB table with an AUTO_INCREMENT column requires at least one key where the auto-increment column is the only **or leftmost** column.”
which suggests, but does not state, support.
I am rather wary of deploying in production something unannounced (which might be only experimentally present) so I hope somebody can point me to the official status of this.
[1]: https://stackoverflow.com/questions/18120088/defining-composite-key-with-auto-increment-in-mysql
[2]: https://stackoverflow.com/questions/5416548/mysql-two-column-primary-key-with-auto-increment
[3]: https://dev.mysql.com/doc/refman/5.7/en/replication-features-auto-increment.html
CREATE TABLE `tbl1` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`data` datetime NOT NULL,
PRIMARY KEY (`id`,`data`)
) ENGINE=InnoDB;
My problem is that, for the life of me, I cannot find a positive statement of support of the feature on MySQL's documentation site - or elsewhere.
the manual contains, in parts unrelated, this rather oblique statement [3]:
“…an InnoDB table with an AUTO_INCREMENT column requires at least one key where the auto-increment column is the only **or leftmost** column.”
which suggests, but does not state, support.
I am rather wary of deploying in production something unannounced (which might be only experimentally present) so I hope somebody can point me to the official status of this.
[1]: https://stackoverflow.com/questions/18120088/defining-composite-key-with-auto-increment-in-mysql
[2]: https://stackoverflow.com/questions/5416548/mysql-two-column-primary-key-with-auto-increment
[3]: https://dev.mysql.com/doc/refman/5.7/en/replication-features-auto-increment.html