prePersist

PrePersist is a lifecycle callback or event in some object-relational mapping frameworks, triggered just before a new entity is persisted (inserted) into the database. It is part of the set of lifecycle events that allow developers to execute custom logic at specific points in an entity’s lifecycle, without manually invoking code around every create operation.

In Java Persistence API (JPA), a method annotated with @PrePersist is invoked before the entity is inserted. The callback method typically takes no arguments and returns void, and it can be public, protected, or package-private. If the method throws a runtime exception, the persist operation can be aborted. PrePersist is executed only for new entities that are being persisted for the first time, and not for entities loaded from the database.

In Doctrine ORM (PHP) and similar frameworks, prePersist serves the same purpose: a method on the entity can be designated to run before the INSERT statement is issued. This can be configured via annotations or mappings. The callback is commonly used to initialize fields, set default values, or perform automatic timestamping (for example, setting a createdAt field) prior to the database operation.

Common uses of prePersist include initializing derived or required fields, setting default values that depend on the entity’s current state, and enforcing invariants before the entity is saved. It is typically paired with a post-persist callback that runs after the record has been created.

Notes: prePersist occurs only for new entities and not for updates. It can be complemented by related events such as preUpdate, postPersist, and postLoad depending on the framework.