Hi,
I'm using nhibernate 1.2.0 with syscache
I have three objects A, B and C. Between A and B there is a one-to-many relationship. Between B and C there is a many-to-many relationship.
The objects A, B and C al use te READ-WRITE cache
The mapping from A to B looks like this:
Code:
[Bag(0, Name = "B", Lazy = true, Fetch = CollectionFetchMode.Join, Cascade = CascadeStyle.All, Inverse = false)]
[Key(1, Column = "a_id")]
[OneToMany(2, ClassType = typeof(B))]
public IList B
{
get { return b; }
set { b = value; }
}
The mapping from B to C looks like this:
Code:
[Bag(0, Name = "C", Lazy = false, Cascade = CascadeStyle.SaveUpdate, Inverse = false, Table = "B_C", Fetch = CollectionFetchMode.Join)]
[Key(1, Column = "b_id")]
[ManyToMany(2, ClassType = typeof(C), Column = "c_id")]
public IList C
{
get { return c; }
set { c = value; }
}
The problem is like this:
When executing the code:
Code:
IQuery query = session.CreateQuery("SELECT a FROM " + typeof(A) + " a WHERE a.id = :id");
query.SetInt64("id", id);
A a = (A)query.UniqueResult();
One object of type A is returned. It has a reference to three objects B (B1, B2 and B3). B1 has a relationship with three C objects C1, C2 and C3.
B2 has a relationship with three C objects C4, C5, C6. B3 has a relationship with one C objcte C7.
So usually when I execute the query the following structure is returned:
Code:
A
|--B1
| |-C1
| |-C2
| |-C3
|
|--B2
| |-C4
| |-C5
| |-C6
|
|--B3
| |-C7
But sometimes when I do exactly the same query this structure is returned:
Code:
A
|--B1
| |-C1
| |-C2
| |-C3
|
|--B1
| |-C1
| |-C2
| |-C3
|
|--B1
| |-C1
| |-C2
| |-C3
|
|--B2
| |-C4
| |-C5
| |-C6
|
|--B2
| |-C4
| |-C5
| |-C6
|
|--B2
| |-C4
| |-C5
| |-C6
|
|--B3
| |-C7
Suddenly A does not have three B objects but 7, the total number of C objects related to the B objects related to C.
When I remove the Fetch = CollectionFetchMode.Join in the A to B mapping the problem seems to be solved. I was trying to reduce the number of selects when I put this in, is this normal behaviour of the CollectionFetchMode.Join? And if so, why doesn't it give the same structure every time?
Thnx,
Sander
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