name of foreign key in innodb table


I'm trying to do a ALTER TABLE to add a foreign key. The code is:

execute "ALTER TABLE table1
                                ADD CONSTRAINT FOREIGN KEY
`const_fk_table1_table2_id` (`table2_id`)
                                REFERENCES `table2` (`id`)
                                ON DELETE CASCADE"

Instead of creating a foreign key constraint with the name
"const_fk_table1_table2_id" it will create one with the name

First I've added an index with : add_index :table1, :table2_id, :name
=> 'fk_table1_table2_id'

Am I doing something wrong?

Problem fixed. The name comes after the CONSTRAINT not the FOREIGN KEY