DeletePolicy

Type Alias: DeletePolicy

DeletePolicy = "CASCADE" | "RESTRICT" | "SET_NULL" | "NONE"

Defined in: packages/models/src/relations.ts:545

What happens to the dependents of a model when it is deleted

Declared on the relation with the @OnDelete <POLICY> JSDoc tag (@CascadeDelete is a synonym of @OnDelete CASCADE), defaulted from the relation kind otherwise:

Policy	Effect when the target of the relation is deleted
`CASCADE`	Delete every dependent, through the repository so its own events fire and it cascades in turn
`RESTRICT`	Refuse the delete with a `409 Conflict` while a dependent exists
`SET_NULL`	Remove the attribute of each dependent (a single link) or the item (a link array)
`NONE`	Do nothing

Relation	Default
`ModelParent` / `BelongTo`	`CASCADE` (`SET_NULL` is refused: a parent is mandatory)
`ModelLink` / `RelateTo` / `ManyToOne` / `OneToOne`	`NONE`
`ModelLinksSimpleArray` / `ModelLinksArray` / `ManyToMany`	`NONE`
`Contains` (declared on the owner)	`CASCADE`: deleting the owner deletes the listed models

The RelationIntegrity service of @webda/core applies the policies, on the repository Delete / Deleted events: Repository.deleteMany emits none, so it never cascades.

class Comment extends UuidModel {
  post: BelongTo<Post>; // CASCADE
  /** @OnDelete RESTRICT */
  author: BelongTo<User>; // a user with comments cannot be deleted
  /** @OnDelete SET_NULL */
  reviewer: RelateTo<User>;
}