By default the name of each field is the id of the entity, if it can be read

from the class metadata by an internal id reader. Otherwise the process will

fall backon an incremental integer.

fall backto using increasing integers.

choice_value

**type**: ``string``, ``callable`` or:class:`Symfony\\Component\\PropertyAccess\\PropertyPath` **default**: id

As for the ``choice_name`` option, ``choice_value``use the id by default.

As for the ``choice_name`` option, ``choice_value``uses the id by default.

It allows an optimization in the:class:``Symfony\\Bridge\\Doctrine\\Form\\ChoiceList\\Loader\\DoctrineChoiceLoader`` which will

only load the ids passed as values while the form submission, preventing all entities,

even with a custom ``query_builder`` to be loaded.

If it can be usefull for API to use an entity property as string value, you

will gain performances by letting this option set by default.

only load the ids passed as values while the form submission.

It prevents all non submitted entities to be loaded from the database, even

when defining the ``query_builder`` option.

If it may be useful to set this option using an entity's property as string

value (e.g for some API), you will gain performances by letting this option set

by default.

..note::