cascading-deletes

I am trying to create a table which captures parent child relationships, like a tree. I would like to maintain only two columns to capture this structure "id" and "parent". I want the database to be able to cascade delete all children when a row is deleted. Below is the Hibernate Entity that I have created, I have added the annotation @OnDelete(action = OnDeleteAction.CASCADE) however, the ON DELETE CASCADE is not added to the table when the table is created by Hibernate. Is this a bug? Or is there something I am missing or not understanding? @Entity public class Tree { @Id @Column(name = "id"

I've following mapping for two tables having a Many-to-Many relationship between them. How do I delete an entry from the mapping table, which is 'TB_EMAIL_GRUPO_ARQUIVO' in my case? I just need to delete the data from this "joining" table and I don´t need to delete it from the "parent tables". GrupoModulo public GrupoModuloMap() { Schema(Const.SCHEMA); Table(Const.TB_EMAIL_GRUPO_MODULO); CompositeId() .KeyReference(x => x.Grupo, Const.ID_GRUPO) .KeyReference(x => x.Modulo, Const.ID_MODULO); Map(x => x.GrupoId).Column(Const.ID_GRUPO).ReadOnly(); Map(x => x.ModuloId).Column(Const.ID_MODULO)

I'm executing a statement like DELETE FROM USER WHERE USER_ID=1; In SQLDeveloper. As the user is referenced in many tables (for example the user has an order, settings, ...) we activated ON DELETE CASCADE so that we do not have to delete each and every row manually. However while developing we are interested to know how many rows and and in which tables are "automatically" deleted by cascade delete. Is there any way to find this out. Either by SQL-Statement, directly in sqldeveloper from a logfile or any other idea? whilst this is not possible with sql%rowcount, it is possible if you write

I have the following Model which I mapped with the Entity Framework: Mitglied -> Auftrag -> Teilprojekt I have set up everything in the database with foreign keys and "on delete cascade". If I perform some tests on the database everything works fine. The problem arises as soon as I use the Entity Framework to add and especially delete objects. Consider the following code: Mitglieder m1 = new Mitglieder(); m1.Name = "erstes"; Auftraege a1 = new Auftraege(); a1.Name = "a1"; m1.Auftraege.Add(a1); Teilprojekte t1 = new Teilprojekte(); t1.Name = "t1"; a1.Teilprojekte.Add(t1); context

class Owner { static hasMany = Dog } class Sitter { static hasMany = Dog } class Dog { static belongsTo = [Owner, Sitter] } My question is: If I create a Dog instance D, a Owner instance O, a Sitter instance S and associate D with both O and S, what happens to O when S gets deleted? Would O still have D? Since it's a cascade-delete, both S and D would get deleted, right? When what happens to O? Would it still have D? I have tested it, it follows the cascade rule: if you delete Owner, Dog will be deleted by cascade, but Sitter will remain. And it's reasonable: Sitter is independent with Owner.