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why can't you have composite primary keys containing autoinc in InnoDB

andieje
andieje asked
on
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Last Modified: 2012-05-10
Hi

For MyISAM and BDB tables you can have an auto_increment field as a secondary part of key, e.g.

CREATE TABLE foo (
   id          INT AUTO_INCREMENT NOT NULL,
   group_field INT NOT NULL,
   name        VARCHAR(128),
 
   PRIMARY KEY(group_field, id)
);
Here's what the manual says about this

In this case, the generated value for the AUTO_INCREMENT column is calculated as MAX(auto_increment_column) + 1 WHERE prefix=given-prefix. This is useful when you want to put data into ordered groups.

Why can't you do this in InnoDB. What's the best way to emulate this in innodb if its even possible.

thanks
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