cascading-deletes

I have to admit, the features of EF 4.1 RC Codefirst, DataAnnotations and FluentAPI are still overwhelming to me. Sometimes I really don't know what I am doing ;-) Please see the following POCOs: public class Country { [Key] public Guid ID { get; set; } [Required] public virtual Currency Currency { get; set; } } public class Currency { [Key] public Guid ID { get; set; } public virtual ICollection<Country> Countries { get; set; } } The general idea: Every country needs to have a currency. But a currency does not need to be assigned to a country at all. If you let EF create the corresponding

May someone help me out. I'm trying something, but I'm (too) new to (my)SQL. I use two tables: Items and Categories. Table Items has a field with foreign key: category_id. I want the table Categories to be kept tidy. So when no item in Items is of category X in Categories, the category X should be deleted from Categories. How do you establish that. I guessed by using DELETE ON CASCADE, but so far it was only deleting corresponding items from Items when I deleted a categorie from Categories. Thanks a lot for helping me! ON DELETE CASCADE is a way of deleting a row when a row it references is

I have two classes A and B with a many-to-one relationship from A to B (multiple A objects may reference the same B). The question is, if the delete rule on the A side is Cascade, will B be deleted only when the last referencing A is deleted or will it be deleted the first time an associated A is deleted. The delete rule for the B side of the relationship is Nullify if that matters. Also, I read in the Core Data docs that the Optional flag matters in some cases. But it wasn't clear how the relationships they were illustrating related to my case. They were talking about a containment case (B is

I am encountering a recurring problem that just makes no sense, and hoping someone (in the Breeze team?) can shed some light. The following model illustrates the entities in question. As you can see, I'm adhering pretty strictly to Entity Framework conventions in my property names, and as a result, if I check in SQL the cascade on delete rules are set by EF code first when it creates the db. Now, when I try to delete a BusUnit manually in SQL, the delete cascades correctly and the corresponding BusUnitDimensions are also deleted, as it should be. Likewise, if I delete a Dimension in SQL, the

Table DISPLAY_TAB below is a self-reference table that can contain both parent and child tabs. A parent tab can have multiple child tabs and a child tab can belong to multiple parents. I'd like to establish a CASCADE DELETE relationship between main table and relationship table DISPLAY_TAB_GROUPING so when either parent or child tab is deleted - relationship is automatically deleted as well (just relationship, not actual tab record). So I am creating a FOREIGN KEY constrain on DISPLAY_TAB_GROUPING for fields TAB_ID_R_1 and TAB_ID_R_2 tables, referencing TAB_ID in DISPLAY_TAB table. And it

Assuming the following "schema/relationship" design what is the recommended practice for handling deletion with cascade delete like operation? Relational Schema: +---------+ +--------+ | Student |-*--------1-[Enrollment]-1--------*-| Course | +---------+ +--------+ MongoDB: +---------+ +--------+ | Student |-*----------------*-| Course | +---------+ +--------+ Given this classic design of enrollment of students to courses, having a collection of courses in students and vice versa seems to be an appropriate data model when using MongoDB (that is nothing for the relationship/enrollment table).