What you are looking for can be achieved by setting up an optional association between Guest and Language entities: protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Guest>() .HasOptional(p => p.PreferredLanguage) .WithMany() .HasForeignKey(p => p.LanguageID); } Unit Test: using (var context = new Context()) { var language = new Language() { LanguageName = “en” }; var guest … Read more
Read this Microsoft article first. Read Me. I use the GUI during design so here is a picture of how it is selected in SSMS. The syntax added to the foreign key is ” ON DELETE CASCADE “
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
Possible reason why you don’t get cascading delete is that your relationship is optional. Example: public class Category { public int CategoryId { get; set; } } public class Product { public int ProductId { get; set; } public Category Category { get; set; } } In this model you would get a Product table … Read more
I think you are misunderstanding the nature of a ManyToMany relationship. You talk about “the corresponding BlogEntry” being deleted. But the whole point of a ManyToMany is that each BlogEntryRevision has multiple BlogEntries related to it. (And, of course, each BlogEntry has multiple BlogEntryRevisions, but you know that already.) From the names you have used, … 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’ll have to implement this as an INSTEAD OF delete trigger on insights, to get it to work. Something like: create trigger T_Insights_D on Insights instead of delete as set nocount on delete from broader_insights_insights where insight_id in (select ID from deleted) or broader_insight_id in (select ID from deleted) delete from Insights where ID in … Read more
This is exactly how cascading deletes behaves in EF. Setting Cascade on a relation in EF designer instructs EF to execute DELETE statement for each loaded realated entity. It doesn’t say anything about ON CASCADE DELETE in the database. Setting Cascade deletion when using EF needs two steps: Set Cascade on relation in EF designer. … 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
I’m pretty sure you can’t simply add on delete cascade to an existing foreign key constraint. You have to drop the constraint first, then add the correct version. In standard SQL, I believe the easiest way to do this is to start a transaction, drop the foreign key, add a foreign key with on delete … Read more