Fluent NHibernate - Delete one entity by Id somehow deleted ALL entities in the DB

[Dev Enthusiast]

I'm new to Fluent NHibernate.  I followed the example at https://github.com/jagregory/fluent-nhibernate/wiki/Getting-started

The example showed how to Create and Read entities.  At run-time, it creates 2 stores.

I added a DeleteByStoreId() method to this sample code.

        public static void DeleteByStoreId(int StoreId)

        {

            var sessionFactory = CreateSessionFactory();

            using (var session = sessionFactory.OpenSession())

            {

                using (var transaction = session.BeginTransaction())

                {

                    var store = session.Get<Store>(StoreId);

                    if (store != null)

                    {

                        session.Delete(store);

                    }

                    transaction.Commit();

                }

            }

        }

When I execute DeleteByStoreId by supplying one of the two existing StoreId, it somehow deletes BOTH stores.  I would have expected it to delete ONLY the one store with the given StoreId.  Can you tell me what I'm doing wrong?

I have to prove to my boss that Fluent NHibernate is capable of doing the CRUD operations so that I get the go ahead to use it in my new project.  Hope you can answer me as soon as possible.

Thank you!

[Dev Enthusiast]

More information.  I used SQL Profiler to monitor the SQL calls.  The example program (https://github.com/jagregory/fluent-nhibernate/wiki/Getting-started) created 2 Store_id's as follows:

Store_id = 105 and = 106

After executing DeleteByStoreId(105), this is the sequence of SQL calls that took place:

2014-03-06 21:41:44.7276|DEBUG|NHibernate.SQL|

     ********************************************************************************

     SELECT store0_.Id as Id10_0_, store0_.Name as Name10_0_ FROM [Store] store0_ WHERE store0_.Id=@p0;

@p0 = 105 [Type: Int32 (0)]

     ********************************************************************************

     SELECT products0_.Store_id as Store2_1_, products0_.Product_id as Product1_1_, product1_.Id as Id8_0_, product1_.Name as Name8_0_, product1_.Price as Price8_0_, product1_.Aisle as Aisle8_0_, product1_.Shelf as Shelf8_0_ FROM StoreProduct products0_ left outer join [Product] product1_ on products0_.Product_id=product1_.Id WHERE products0_.Store_id=@p0;

@p0 = 105 [Type: Int32 (0)]

     ********************************************************************************

     SELECT storesstoc0_.Product_id as Product1_1_, storesstoc0_.Store_id as Store2_1_, store1_.Id as Id10_0_, store1_.Name as Name10_0_ FROM StoreProduct storesstoc0_ left outer join [Store] store1_ on storesstoc0_.Store_id=store1_.Id WHERE storesstoc0_.Product_id=@p0;

@p0 = 307 [Type: Int32 (0)]

     ********************************************************************************

     SELECT storesstoc0_.Product_id as Product1_1_, storesstoc0_.Store_id as Store2_1_, store1_.Id as Id10_0_, store1_.Name as Name10_0_ FROM StoreProduct storesstoc0_ left outer join [Store] store1_ on storesstoc0_.Store_id=store1_.Id WHERE storesstoc0_.Product_id=@p0;

@p0 = 308 [Type: Int32 (0)]

     ********************************************************************************

     SELECT storesstoc0_.Product_id as Product1_1_, storesstoc0_.Store_id as Store2_1_, store1_.Id as Id10_0_, store1_.Name as Name10_0_ FROM StoreProduct storesstoc0_ left outer join [Store] store1_ on storesstoc0_.Store_id=store1_.Id WHERE storesstoc0_.Product_id=@p0;

@p0 = 309 [Type: Int32 (0)]

     ********************************************************************************

     SELECT storesstoc0_.Product_id as Product1_1_, storesstoc0_.Store_id as Store2_1_, store1_.Id as Id10_0_, store1_.Name as Name10_0_ FROM StoreProduct storesstoc0_ left outer join [Store] store1_ on storesstoc0_.Store_id=store1_.Id WHERE storesstoc0_.Product_id=@p0;

@p0 = 310 [Type: Int32 (0)]

     ********************************************************************************

     SELECT products0_.Store_id as Store2_1_, products0_.Product_id as Product1_1_, product1_.Id as Id8_0_, product1_.Name as Name8_0_, product1_.Price as Price8_0_, product1_.Aisle as Aisle8_0_, product1_.Shelf as Shelf8_0_ FROM StoreProduct products0_ left outer join [Product] product1_ on products0_.Product_id=product1_.Id WHERE products0_.Store_id=@p0;

@p0 = 106 [Type: Int32 (0)]

     ********************************************************************************

     SELECT storesstoc0_.Product_id as Product1_1_, storesstoc0_.Store_id as Store2_1_, store1_.Id as Id10_0_, store1_.Name as Name10_0_ FROM StoreProduct storesstoc0_ left outer join [Store] store1_ on storesstoc0_.Store_id=store1_.Id WHERE storesstoc0_.Product_id=@p0;

@p0 = 311 [Type: Int32 (0)]

     ********************************************************************************

     SELECT storesstoc0_.Product_id as Product1_1_, storesstoc0_.Store_id as Store2_1_, store1_.Id as Id10_0_, store1_.Name as Name10_0_ FROM StoreProduct storesstoc0_ left outer join [Store] store1_ on storesstoc0_.Store_id=store1_.Id WHERE storesstoc0_.Product_id=@p0;

@p0 = 312 [Type: Int32 (0)]

     ********************************************************************************

     SELECT staff0_.Store_id as Store4_1_, staff0_.Id as Id1_, staff0_.Id as Id7_0_, staff0_.FirstName as FirstName7_0_, staff0_.LastName as LastName7_0_, staff0_.Store_id as Store4_7_0_ FROM [Employee] staff0_ WHERE staff0_.Store_id=@p0;

@p0 = 106 [Type: Int32 (0)]

     ********************************************************************************

     SELECT staff0_.Store_id as Store4_1_, staff0_.Id as Id1_, staff0_.Id as Id7_0_, staff0_.FirstName as FirstName7_0_, staff0_.LastName as LastName7_0_, staff0_.Store_id as Store4_7_0_ FROM [Employee] staff0_ WHERE staff0_.Store_id=@p0;

@p0 = 105 [Type: Int32 (0)]

     ********************************************************************************

     DELETE FROM StoreProduct WHERE Store_id = @p0;

@p0 = 105 [Type: Int32 (0)]

     ********************************************************************************

     DELETE FROM StoreProduct WHERE Store_id = @p0;

@p0 = 106 [Type: Int32 (0)]

     ********************************************************************************

     Batch commands:

command 0:DELETE FROM [Product] WHERE Id = @p0;

@p0 = 307 [Type: Int32 (0)]

command 1:DELETE FROM [Product] WHERE Id = @p0;

@p0 = 308 [Type: Int32 (0)]

command 2:DELETE FROM [Product] WHERE Id = @p0;

@p0 = 309 [Type: Int32 (0)]

command 3:DELETE FROM [Product] WHERE Id = @p0;

@p0 = 311 [Type: Int32 (0)]

command 4:DELETE FROM [Product] WHERE Id = @p0;

@p0 = 312 [Type: Int32 (0)]

     ********************************************************************************

     Batch commands:

command 0:DELETE FROM [Employee] WHERE Id = @p0;

@p0 = 256 [Type: Int32 (0)]

command 1:DELETE FROM [Employee] WHERE Id = @p0;

@p0 = 257 [Type: Int32 (0)]

     ********************************************************************************

     Batch commands:

command 0:DELETE FROM [Store] WHERE Id = @p0;

@p0 = 106 [Type: Int32 (0)]

     ********************************************************************************

     Batch commands:

command 0:DELETE FROM [Product] WHERE Id = @p0;

@p0 = 310 [Type: Int32 (0)]

     ********************************************************************************

     Batch commands:

command 0:DELETE FROM [Employee] WHERE Id = @p0;

@p0 = 258 [Type: Int32 (0)]

command 1:DELETE FROM [Employee] WHERE Id = @p0;

@p0 = 259 [Type: Int32 (0)]

command 2:DELETE FROM [Employee] WHERE Id = @p0;

@p0 = 260 [Type: Int32 (0)]

     ********************************************************************************

     Batch commands:

command 0:DELETE FROM [Store] WHERE Id = @p0;

@p0 = 105 [Type: Int32 (0)]

     ********************************************************************************

When I put a breakpoint in DeleteByStoreId(), I can see that 

var store = session.Get<Store>(StoreId);

only returns the element of Store_Id=105.  So, why would it go and delete Store_id=106 as well??

Thanks.

[Chris Bingham]

Sounds like a cascade is wrong somewhere...

I notice that procuct.stores stocked in is cascade.all that seems pretty wrong to me (suspect it means if I delete a product it will also delete the store)

Hth, Chris

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[Oskar Berggren]

I would concur that the cascading rules are too liberal. Judging from the text in the article it sounds like a lazy way to add an object graph and only having to call Save() on a single "starting point".

I find that when it comes to cascading it's good to think about object ownership and lifetime. Does A own B? Is the lifetime of B controlled by (the lifetime of) A? Is to, let add/delete cascade from A to B (but not in the other direction).

/Oskar