..index::

single: Doctrine

Databases and Doctrine

Databases andtheDoctrine ORM

One of the most common and challenging tasks for any application

involves persisting and reading information to and from a database. Although

not possible to mix YAML metadata definitions with annotated PHP entity

class definitions.

..note::

If using the Doctrine ODM the mapping of the `id` field is slightly different. You should define the field as normal, under the `fields` key, and add `id: true` to the definition. See the `Doctrine MongoDB YAML Driver documentation<http://docs.doctrine-project.org/projects/doctrine-mongodb-odm/en/latest/reference/yml-mapping.html>`_ for more info.

Using the above format will result in the error "No identifier/primary key specified for Document '<document class>'. Every Document must have an identifier/primary key.".

..tip::

The table name is optional and if omitted, will be determined automatically