php - Doctrine Many-to-many - how to access join(pivot) table? -

i'm making many-to many relatioships categories , articles. article must have "main" category, in oters categories "rel="canonical"" placed. , logically place in join table. in laravel there wery simple mechanism so: http://laravel.com/docs/5.0/eloquent#working-with-pivot-tables

but read association mapping in doctrine: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/association-mapping.html - , there no info how access or modify table. there way in doctrine?

at point adding field pivot table no longer pivot table. need create entity access additional column there no way doctrine know accommodate in optional 3rd column of pivot table.

if need access can create raw doctrine query access table directly.