#1381 new

DataMapper automigrate has problem with Auto_increment+ index on MySQL table creation

Reported by incubaton | August 3rd, 2010 @ 09:53 AM

When you add an Integer field to a MySQL table with an auto_increment option you have to add an index or a primary key to make it works.

In DataMapper when you add a field in a table with an index (:unique => true for exemple), the addition of the index is done after the CREATE TABLE in an ALTER TABLE.

Now i create my model :

CODE class TestOneTestTwo

include DataMapper::Resource
storage_names[:default] = 'test_one__test_two'
belongs_to  :test_one, :key => true
belongs_to  :test_two, :key => true
property    :test,     String, :unique => true
property    :id,       Serial, :unique => true, :key => false


There is query generated :

QUERY CREATE TABLE test_one__test_two (
test_one_id INT(10) UNSIGNED NOT NULL, test_two_id INT(10) UNSIGNED NOT NULL, PRIMARY KEY(test_one_id, test_two_id))
ENGINE = InnoDB CHARACTER SET utf8 COLLATE utf8_general_ci

As you can see, we got the id field with the AUTO_INCREMENT as wished but no UNIQUE index so MySQL render an error :

"#1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key"

(if i put a string field instead of the id field, and then have no AUTO_INCREMENT on the field, the creation of the table will be successful and the INDEX will be added in an ALTER TABLE just after the creation. )

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