cascading-deletes

is there a script that can be used to enable cascaded deletion for existing tables. Thanks. VMAtm ALTER TABLE [wm].[TABLE_NAME] WITH NOCHECK ADD CONSTRAINT [FK_TABLE_NAME_PARENT_TABLE_NAME] FOREIGN KEY([FOREIGN_KEY]) REFERENCES [wm].[PARENT_TABLE_NAME] ([PRIVATE_KEY]) ON DELETE CASCADE GO TABLE_NAME : name of the table where the children are stored. PARENT_TABLE_NAME : name of the table where the parents are stored. This placeholders can be equal FK_TABLE_NAME_PARENT_TABLE_NAME : just name for the constraint FOREIGN_KEY : field in the child table for the connection with the parents, for

I'm not sure exactly sure what the correct terminology is for my question so I'll just explain what I want to do. I have a directed graph and after I delete a node I want all independently related nodes to be removed as well. Here's an example: Say, I delete node '11', I want node '2' to be deleted as well(and in my own example, they'll be nodes under 2 that will now have to be deleted as well) because its not connected to the main graph anymore. Note, that node '9' or '10' should not be deleted because node '8' and '3' connect to them still. I'm using the python library networkx. I searched

I'm using Entity Framework 4 and have a one-to-many relationship between a parent and child entity. I'm trying to delete a child using the parent repository by removing it from the parent's children collection: public virtual void RemoveChild(Child child) { children.Remove(child); } When I try to save the changes I get the following error: A relationship from the 'ParentChild' AssociationSet is in the 'Deleted' state. Given multiplicity constraints, a corresponding 'Child' must also in the 'Deleted' state. Surely I don't have to delete the child entity explicitly using a child repository! It

I hit an issue when trying to delete records due to FK constraints. I therefore went back to the drawing board and am trying to specify how the relationship should work. Here are my code first classes: public class MemberDataSet { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int Id { get; set; } public int? DeferredDataId { get; set; } [ForeignKey("DeferredDataId")] public virtual DeferredData DeferredData { get; set; } } public class DeferredData { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int Id { get; set; } //other properties

I have got 3 tables: lt_hdefaults , lt_hperiods and lt_hrules . In lt_hdefaults , there is one row for a property for a particular year. In the lt_hperiods table, there could be more than one period, call them seasons. In the lt_hrules table, there could be more than one rule for each period. Now, what I could not make work: when the user deletes a record from lt_hdefaults , other data related to the deleted record should be removed from lt_hperiods and lt_hrules table. I am trying to achieve this by using FOREIGN KEY (lt_year,lt_id) REFERENCES lt_hdefaults(lt_year,lt_id) ON DELETE CASCADE

Some database features, such as SELECT ... FOR UPDATE and ON DELETE CASCADE , are implicitly vulnerable to deadlocks because the database does not specify what locking order will be used. I found two discussions that hint that this behavior isn't specified by the SQL standard, not to mention specific implementations. As such, I'm operating under the assumption that we cannot control the locking order (at least, it's not obvious how to do so). How are we supposed to avoid database deadlocks if we cannot rely on the locking order? If we're not supposed to avoid deadlocks (you're going to have to

I have a 1..* relationship between User and Post . (one user has many posts) Post has a FK called "UserId", which maps to the "UserId" field on User table. I tried to set this FK as Cascade UPDATE/DELETE, but i get this error: 'Users' table saved successfully 'Posts' table - Unable to create relationship 'FK_Posts_Users'. Introducing FOREIGN KEY constraint 'FK_Posts_Users' on table 'Posts' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint. See previous errors. I have a table