How to Properly Implement On Delete Cascade in Doctrine2?

Doctrine2: Understanding On Delete Cascade

The concept of On Delete Cascade in Doctrine2 allows for the automatic deletion of child records when the parent record is deleted. This feature ensures data integrity by maintaining referential integrity.

Implementing On Delete Cascade in Doctrine2

To implement On Delete Cascade, there are two approaches:

1. Object-Relational Mapping (ORM) Level:

   • Specify cascade={"remove"} in the association within the child entity.
   • This instructs Doctrine to remove all associated child objects when the parent object is deleted. However, it does not affect the database structure.

2. Database Level:

   • Add onDelete="CASCADE" to the join column of the association in the child entity.
   • This creates a database constraint that automatically deletes child records when the referenced parent record is deleted.

Correcting Your Entities

In your example, you have used the ORM-level approach but missed the onDelete="CASCADE" attribute on the join column. To correct this, modify the Child.php entity as follows:

<code class="php">/**
 * @ORM\ManyToOne(targetEntity="Father", cascade={"remove"})
 * @ORM\JoinColumn(name="father_id", referencedColumnName="id", onDelete="CASCADE")
 *
 * @var Father
 */
private $father;</code>

注意事項

• The ORM-level cascade cascade={"remove"} as currently implemented will also delete the parent object when a child object is deleted. This is not typically desired.
• Therefore, it is recommended to use the database-level cascade with onDelete="CASCADE" for better control over the deletion behavior.

The above is the detailed content of How to Properly Implement On Delete Cascade in Doctrine2?. For more information, please follow other related articles on the PHP Chinese website!