许多人加入Fluent NHibernate的自我问题

Question

I am a complete Fluent Newbie and while I have found a lot on the 'net about Many-to-many joins, I havent found much in my current scenario.

Note: Ok, this may be rubbish design and I may be better off making seperate tables, insults about the design are appreciated :)

I have a table like so:

And classes such:

[Serializable]
public class Transaction : Entity
{
    [DomainSignatureAttribute]
    public virtual long TransactionId { get; protected internal set; }
    public virtual long AccountId { get; set; }
    protected internal virtual short TransactionTypeId { get; set; }
    protected internal virtual short TransactionStatusId { get; set; }
    public virtual DateTime DateCreated { get; set; }
    public virtual DateTime DateEffective { get; set; }
    public virtual Decimal Amount { get; set; }

    public virtual IList<TransactionLink> ChildTransactions { get; set; }
    public virtual IList<TransactionLink> ParentTransactions { get; set; }

    public Transaction()
    {
        ChildTransactions = new List<TransactionLink>();
        ParentTransactions = new List<TransactionLink>();
    }

    /// <summary>
    /// Use this to add a payment to a charge to pay it off, or to add a refund on a payment to un-pay it
    /// </summary>
    /// <param name="inTransaction"></param>
    /// <param name="inAmount"></param>
    public virtual void AddChildTransaction(Transaction inTransaction, Decimal inAmount)
    {
        TransactionLink link = new TransactionLink()
                                            {
                                                TransactionParent = this,
                                                TransactionChild = inTransaction,
                                                Amount = inAmount
                                            };

        if (!ChildTransactions.Contains(link))
            ChildTransactions.Add(link);

        if (!inTransaction.ParentTransactions.Contains(link))
            inTransaction.ParentTransactions.Add(link);
    }

    /// <summary>
    /// You probably shouldnt be using this.
    /// </summary>
    /// <param name="inTransaction"></param>
    /// <param name="inAmount"></param>
    public virtual void AddParentTransaction(Transaction inTransaction, Decimal inAmount)
    {
        TransactionLink link = new TransactionLink()
                                            {
                                                TransactionChild = this,
                                                TransactionParent = inTransaction,
                                                Amount = inAmount
                                            };

        if (!inTransaction.ChildTransactions.Contains(link))
            inTransaction.ChildTransactions.Add(link);

        if (!ParentTransactions.Contains(link))
            ParentTransactions.Add(link);
    }
}

And

[Serializable]
public class TransactionLink : Entity
{
    public virtual Int64 TransactionIdParent { get; protected internal set; }
    public virtual Transaction TransactionParent { get; set; }

    public virtual Int64 TransactionIdChild { get; set; }
    public virtual Transaction TransactionChild { get; protected internal set; }

    public virtual DateTime LastModifiedOn { get; set; }
    public virtual Decimal Amount { get; set; }

    #region Override comparison - as this is a composite key we need to custom roll our comparison operators

    #endregion
}

Maps:

public TransactionMap()
    {
        Id(x => x.TransactionId);

        Map(x => x.AccountId);
        Map(x => x.TransactionTypeId);
        Map(x => x.TransactionStatusId);
        Map(x => x.DateCreated);
        Map(x => x.DateEffective);
        Map(x => x.Amount);
        HasMany(x => x.ParentTransactions).Cascade.None().KeyColumn("TransactionIdParent").LazyLoad();
        HasMany(x => x.ChildTransactions).Cascade.All().KeyColumn("TransactionIdChild").LazyLoad();
    }

and

public TransactionLinkMap()
    {
        CompositeId()
            .KeyProperty(x => x.TransactionIdParent, "TransactionIdParent")
            .KeyProperty(x => x.TransactionIdChild, "TransactionIdChild");

        References(x => x.TransactionParent).Column("TransactionIdParent").Cascade.SaveUpdate().LazyLoad();
        References(x => x.TransactionChild).Column("TransactionIdChild").Cascade.All().LazyLoad();

        Version(x => x.LastModifiedOn);
        Map(x => x.Amount);
    }

I am tweaking things around and getting all kinds of errors from nHibernate - someone please tell me what is the best way to go about this??

Answer 1

Gah, problem found - after Jonas pointed to the other setup I figured the issue must be with a composite key - the answer? Don't use a composite key!

Even with the Version() property set nHibernate saw all Transient objects to be the same, thus was messing up when I was trying to add 3 Transactions in one hit.

The solution to this problem, if anyone else hits the same thing, is to add an auto-increment key to the many to many table and use that as a key within nHibernate, which makes it much easier for nHibernate to differenciate between Transient objects!