This is because while EF Core represents relationships using navigations as well of foreign keys, databases have only foreign keys and no navigations. There are two options to avoid this referential constraint violation: The first option in only valid for optional relationships where the foreign key property (and the database column to which it is mapped) must be nullable. The following table shows the result of each OnDelete value on the foreign key constraint created by EF Core migrations or EnsureCreated. The conflict occurred in database "Scratch", table "dbo.Blogs", column 'OwnerId'. ASP.NET Forums / Data Access / ADO.NET, Entity Framework, LINQ to SQL, NHibernate / Cascade delete entitiyframework core Cascade delete entitiyframework core RSS 1 reply :D Delete Data in Disconnected Scenario in Entity Framework Core. Each table covers one of: Entities in the database that have not been loaded into the context, Deleting a blog will cascade delete all the related posts, Deleting the author of posts will cause the authored posts to be cascade deleted, Deleting the owner of a blog will cause the blog to be cascade deleted. to be much quicker than doing manual deletions for every single entity (most likely not as fast as the stored procedure but hopefully faster than manual deletions through-and-through). If you use entity framework database first, As entities manually is exceptionally slow. Cascade Delete - EF Core. Cascading deletes are needed when a dependent/child entity can no longer be associated with its current principal/parent. But when management wants to delete the customer records from primary registration table, the records from purchase table should also be deleted. You can not use the ALTER TABLE statement to add a foreign key with cascade delete in SQLite. seconds). In the following example, a cascade delete is configured on the relationship between Blog and Post, so the post entity is deleted from the database. This means that the foreign key value can be set to null when the current principal/parent is deleted or is severed from the dependent/child. Cascading delete refers to the action of removing records associated by a foreign key relationship to a record that is the target of a deletion action. Here's a super simplified version of my model: User {UserID, Name} Recipe {RecipeID, UserID} Ingredient {IngredientID, UserID} RecipeIngredient {RecipeID, IngredientID} *RecipeIngredient is … I use the [CascadeDelete] attribute like follows in an entity, which successfully adds the "Cascade" delete rule to the Parent-Child relation. Conclusion. Cascading doesn't work because for all the objects I'd like to cascade upon deletion, there will be multiple or cyclical cascade paths which is not allowed (for some bizarre reason) in SQL Server. We're trying to get cascading to work in EF in the hopes of at least making it a bit faster. But I'm not sure if this is the best way. If we know that the database is configured like this, then we can delete a blog without first loading posts and the database will take care of deleting all the posts that were related to that blog. – … I'm still not able to get cascading to work in EF and so deleting all the The EF Core in-memory database does not currently support cascade deletes in the database. For orphans, the principal/parent entity still exists, but is no longer related to the dependent/child entities. Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. There are two ways to handle this situation: Taking the first approach with our example, we could make the blog-owner relationship optional by giving it a nullable foreign key property: An optional relationship allows the blog to exist without an owner, which means cascade delete will no longer be configured by default. 3) File is parsed and new data is made into new entities. Prior to EF Core it didn't have a name and was not possible to change. The exact timing of when cascading behaviors happen to tracked entities can be controlled using ChangeTracker.CascadeDeleteTiming and ChangeTracker.DeleteOrphansTiming. EF Core API builds and executes the DELETE statement in the database for the entities whose EntityState is Deleted. There is no difference in deleting an entity in the connected and disconnected scenario in EF Core. I will see about setting cascade on delete in the database. but attempting to create a SQL Server database with these cascades configured results in the following exception: Microsoft.Data.SqlClient.SqlException (0x80131904): Introducing FOREIGN KEY constraint 'FK_Posts_Person_AuthorId' on table 'Posts' may cause cycles or multiple cascade paths. See Changing Foreign Keys and Navigations for more information. The only values that will cause cascading behaviors on the database are Cascade and SetNull. If the foreign-key does We figured if it takes an extra while to delete the entities and then parse the file, that would be fine so long as the final step (saving to Then the delete successfully removes both the city and the zip code. See Relationships for more information on modeling relationships. The following example shows how to setup and cascade works when deleting record from parent table. If possible, could you please share a simple demo, which could reproduce the issue via OneDrive. Required relationships are configured to use cascade deletes by default. I am running into an issue DELETE CASCADE in Entity Framework Core that I can't seem to find a good solution to. From what I gather, it seems that during a transaction like this, as soon as 4) Once file parsing is done, new entities are saved to database (with context.SaveChangesAsync()). If delete rule for Department.employees is also nullify, then when you delete the department, its employees are not let go. 2) Delete stored procedure runs to delete old data. If you use entity framework database first, As The statement has been terminated. For cascade delete, this severing happens because the principal/parent is itself deleted. The tables in the following sections cover what happens to dependent/child entities when the principal/parent is deleted, or its relationship to the dependent/child entities is severed. Using cascading deletes and cascading nulls in the database at the same time will almost always result in relationship cycles when using SQL Server. I suppose this is why setting cascade on delete in the data model doesn't work? I'm working on an ASP.NET MVC 6 project with Entity-Framework Core (version "EntityFramework.Core": "7.0.0-rc1-final") backed by a SQL Server 2012 express DB.. Based on your description, I create a simple with database cascade delete by using database first, I do not change anything in entity in EDMX file. it. The only reason this didn't seem to be an issue before was that between the time when the delete stored procedure was run and the time when it began to parse the file, a new context was injected into the file parsing function. How to Add a Foreign Key with Cascade Delete to an Existing Table. I would prefer ON CASCADE DELETE just because in my opinion it better describes model and reveals creator's intention. So in that case a single delete query of master table can delete master tables data as well as child tables ... not working in sql 2008. DA924x said,  you need to alter your database table with DELETE CASCADE, like this: MSDN Community Support This document describes cascade deletes (and deleting orphans) from the perspective of updating the database. Name the project Notes and, to speed things up, check Use Core Dataat the bottom. For example, if you didn't define the Department.InstructorID property as nullable, EF would configure a cascade delete rule to delete the department when you delete the instructor, which isn't what you want to have happen. Created by EF Core it did n't work deleted by EF Core in-memory database does not currently Support deletes. Delete behaviors for related entities when the relationship to their required principal/parent is deleted or severed! 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