From http://dev.mysql.com/doc/refman/5.6/en/innodb-restrictions.html Cascaded foreign key actions do not activate triggers In other words, you cannot use the trigger with cascaded deleting. Also see related bugs: MySQL: https://bugs.mysql.com/bug.php?id=11472 MariaDB: https://jira.mariadb.org/browse/MDEV-19402
What you are doing is the best and most optimal way of doing it in Mongo. I am in a similar situation and after going all possible implementations of the N:M design pattern, have also arrived to this same solution. Apparently, This is not a mongodb thing, but more of a concept of NoSQL, wherein, … Read more
It is theoretically correct but SQL server (not Entity framework) doesn’t like it because your model allows single employee to be a member of both First and Second team. If the Team is deleted this will cause multiple delete paths to the same Employee entity. This cannot be used together with cascade deletes which are … Read more
Nope, you’d need to run multiple statements. Because you need to delete from two tables, consider creating a temp table of the matching ids: SELECT U.Id INTO #RecordsToDelete FROM Users U JOIN LinkingTable J ON U.Id = J.U_Id … And then delete from each of the tables: DELETE FROM Users WHERE Id IN (SELECT Id … Read more
Your database should delete rows from quizQuestions in case someone is deleting from quizzes or from questions. It will ignore the entire foreign key constraint in case foreign key support is turned off and you have just regular columns that can contain any value. SQLite defaults to PRAGMA foreign_keys = OFF every time you open … Read more
Do you have associations in this graph that cascade a persist back to the thing being deleted? If so, the JPA spec states clearly that the provider is to cancel the delete in such a case. If this is the case, Hibernate writes out a log statement saying “un-scheduling entity deletion […]”. You could see … Read more
You will have to use the fluent API to do this. Try adding the following to your DbContext: protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<User>() .HasOptional(a => a.UserDetail) .WithOptionalDependent() .WillCascadeOnDelete(true); }
Just a note for those who run into this issue as well, there is now an built-in solution in Django 1.3. See the details in the documentation django.db.models.ForeignKey.on_delete Thanks for editor of Fragments of Code site to point it out. The simplest possible scenario just add in your model FK field definition: on_delete=models.SET_NULL
From experience, listening to notifications other than NSManagedObjectContextDidSaveNotification is a big mess and can lead to relying on properties not yet updated. The detail view controller should listen to NSManagedObjectContextDidSaveNotification notifications, which are thrown after cascade is applied. You can then check by several means if the current object is valid or not (you can … Read more
The basic difference between them is: When using the orphanRemoval=true option Doctrine makes the assumption that the entities are privately owned and will NOT be reused by other entities. If you neglect this assumption your entities will get deleted by Doctrine even if you assigned the orphaned entity to another one. Say your User has … Read more