many2many ondelete:CASCADE

[ghost]

If I set on_delete to CASCADE on a many2many relation, for example:

type ModelA struct {
	Id      uint64    `pg:"id"`
	ModelBs []*ModelB `pg:"many2many:modela_to_modelbs,on_delete:CASCADE"`
}

type ModelB struct {
	Id      uint64    `pg:"id"`
	ModelAs []*ModelA `pg:"many2many:modela_to_modelbs,on_delete:CASCADE"`
}

type ModelAToModelB struct {
	ModelAId uint64 `pg:"model_a_id,type:bigint"`
	ModelBId uint64 `pg:"model_a_id,type:bigint"`

        //nolint
	tableName struct{} `pg:"modela_to_modelbs"`
}

When I delete a ModelA, will all the ModelB's that are related to that ModelA also be deleted, or just the ModelAToModelB's?

[vmihailenco]

on_delete only works for has-one relation and it is only used when creating table schema with CreateTable . Specifically it adds FOREIGN_KEY some_id ON DELETE CASCADE - https://www.postgresql.org/docs/13/sql-createtable.html

This is fixed in Bun by allowing to manually specify foreign keys - https://bun.uptrace.dev/guide/queries.html#creating-tables

[ghost]

Okay, thanks for getting back to me. I'll delete the relations manually. 👍

[vmihailenco]

...or you can just update the table definition manually via migrations etc :)