Separating Concerns using Embeddables

Embeddables are classes which are not entities themself, but are embedded in entities and can also be queried in DQL. You’ll mostly want to use them to reduce duplication or separating concerns.

For the purposes of this tutorial, we will assume that you have a User class in your application and you would like to store an address in the User class. We will model the Address class as an embeddable instead of simply adding the respective columns to the User class.

  • PHP
    <?php
    
    /** @Entity */
    class User
    {
        /** @Embedded(class = "Address") */
        private $address;
    }
    
    /** @Embeddable */
    class Address
    {
        /** @Column(type = "string") */
        private $street;
    
        /** @Column(type = "string") */
        private $postalCode;
    
        /** @Column(type = "string") */
        private $city;
    
        /** @Column(type = "string") */
        private $country;
    }
    
  • XML
    <doctrine-mapping>
        <entity name="User">
            <embedded name="address" class="Address" />
        </entity>
    
        <embeddable name="Address">
            <field name="street" type="string" />
            <field name="postalCode" type="string" />
            <field name="city" type="string" />
            <field name="country" type="string" />
        </embeddable>
    </doctrine-mapping>
    
  • YAML
    User:
      type: entity
      embedded:
        address:
          class: Address
    
    Address:
      type: embeddable
      fields:
        street: { type: string }
        postalCode: { type: string }
        city: { type: string }
        country: { type: string }
    

In terms of your database schema, Doctrine will automatically inline all columns from the Address class into the table of the User class, just as if you had declared them directly there.

Column Prefixing

By default, Doctrine names your columns by prefixing them, using the value object name.

Following the example above, your columns would be named as address_street, address_postalCode...

You can change this behaviour to meet your needs by changing the columnPrefix attribute in the @Embeddable notation.

The following example shows you how to set your prefix to myPrefix_:

  • PHP
    <?php
    
    /** @Entity */
    class User
    {
        /** @Embedded(class = "Address", columnPrefix = "myPrefix_") */
        private $address;
    }
    
  • XML
    <entity name="User">
        <embedded name="address" class="Address" column-prefix="myPrefix_" />
    </entity>
    
  • YAML
    User:
      type: entity
      embedded:
        address:
          class: Address
          columnPrefix: myPrefix_
    

To have Doctrine drop the prefix and use the value object’s property name directly, set columnPrefix=false (not yet supported with XML configuration):

  • PHP
    <?php
    
    /** @Entity */
    class User
    {
        /** @Embedded(class = "Address", columnPrefix = false) */
        private $address;
    }
    
  • YAML
    User:
      type: entity
      embedded:
        address:
          class: Address
          columnPrefix: false
    

DQL

You can also use mapped fields of embedded classes in DQL queries, just as if they were declared in the User class:

SELECT u FROM User u WHERE u.address.city = :myCity
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