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Using Doctrine Naming Strategies in Symfony

Feb 20, 2016

Frequently, I’m stumbling upon very verbose Doctrine metadata definitions that translate each and every table and column definition from camelCase names to names separated by underscores, e.g. firstName to first_name. But did you know that can simply get rid of all this noise by implementing a Doctrine naming strategy?

Let’s consider such a verbose sample entity definition for a person:

Acme\MyService\Domain\Person:
    type: entity
    table: person
    # ...
    fields:
        firstName:
            column: first_name
            type: string
        lastName:
            column: last_name
            type: string
        createdAt:
            column: created_at
            type: datetime

Or, using annotations:

<?php

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="person")
 */
class Person
{
    // ...
    
    /**
     * @ORM\Column(name="first_name", type="string")
     */
    private $firstName;
    
    /**
     * @ORM\Column(name="last_name", type="string")
     */
    private $lastName;
    
    /**
     * @ORM\Column(name="created_at", type="datetime")
     */
    private $created_at;
    
    // ...
}    

It seems quite verbose to translate the camelCase entity table name and properties names to under_score table and column names, e.g. Person to person, firstName to first_name etc. Furthermore, it is quite prone to become inconsistent if someone forgets it for a column that’s added later. So why not automate the translation?

Doctrine Naming Strategies to the rescue! Doctrine naming strategies allow to define how entity class names and properties are translated to table and column names if they are not provided by the metadata. By default, Doctrine does not change anything and in the example above you’d end up with a Person table and the column names firstName, lastName etc. But by configuring the Underscore Naming Strategy you’ll get exactly what you want – without all the table and column config noise in your metadata:

Acme\MyService\Domain\Person:
    type: entity
    # ...
    fields:
        firstName:
            type: string
        lastName:
            type: string
        createdAt:
            type: datetime

Or, using annotations:

<?php

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 */
class Person
{
    // ...
    
    /**
     * @ORM\Column(type="string")
     */
    private $firstName;
    
    /**
     * @ORM\Column(type="string")
     */
    private $lastName;
    
    /**
     * @ORM\Column(type="datetime")
     */
    private $created_at;
    
    // ...
}    

How to set this up? If using Symfony, it’s as simple as adding a configuration parameter doctrine.orm.entity_managers.default.naming_strategy to your config.yml:

doctrine:
    dbal:
        # ...
    orm:
        # ...
        entity_managers:
            default:
                naming_strategy: doctrine.orm.naming_strategy.underscore

If using plain PHP, you can check the Doctrine docs for the few lines you need to add.

By providing a custom implementation of Doctrine\ORM\Mapping\NamingStrategy, you can also easily define your own naming strategy. This comes in handy if for example you need to follow naming guidelines like prefixing every table name, e.g. by tbl_.

By the way, as string is always the default data type, so you can even skip this config for simple columns by only putting a tilde ~ character:

Acme\MyService\Domain\Person:
    type: entity
    # ...
    fields:
        firstName: ~
        lastName: ~
        createdAt:
            type: datetime

When using annotations, just leave out the type definition:

<?php

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 */
class Person
{
    // ...
    
    /**
     * @ORM\Column(type="string")
     */
    private $firstName;
    
    /**
     * @ORM\Column(type="string")
     */
    private $lastName;
    
    /**
     * @ORM\Column(type="datetime")
     */
    private $created_at;
    
    // ...
}

This will finally result in the following SQL definition, which is the same as for the verbose metadata definition from the beginning:

CREATE TABLE `person` (
/* ... */
`first_name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`last_name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`created_at` datetime NOT NULL,
PRIMARY KEY (`person_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

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