具有Composite-Id保存問題的NHibernate實體

Question

為了使自己清楚，我創建了一個最基本的案例來描述我的問題。 假設我有3個表：

CREATE TABLE [dbo].[Product](
    [ProductID] [int] IDENTITY(1,1) NOT NULL,
    [ProductName] [varchar](50) NOT NULL,
 CONSTRAINT [PK_Product] PRIMARY KEY CLUSTERED ( [ProductID] ASC )
) ON [PRIMARY]

CREATE TABLE [dbo].[OrderHeader](
    [HeaderID] [int] IDENTITY(1,1) NOT NULL,
    [Comment] [varchar](100) NULL,
 CONSTRAINT [PK_OrderHeader] PRIMARY KEY CLUSTERED ( [HeaderID] ASC )
) ON [PRIMARY]

CREATE TABLE [dbo].[OrderDetail](
    [HeaderID] [int] NOT NULL, /* FK to OrderHeader table */
    [ProductID] [int] NOT NULL, /* FK to Product table */
    [CreatedOn] [datetime] NOT NULL,
 CONSTRAINT [PK_OrderDetail] PRIMARY KEY CLUSTERED 
(
    [HeaderID] ASC, 
    [ProductID] ASC 
)
) ON [PRIMARY]

我創建了相應的實體類和映射類。

public class Product {
    public virtual int? Id { get; set; }

    public virtual string Name { get; set; }
}

public class ProductMap : ClassMap<Product> {
    public ProductMap() {
        Table("Product");

        Id(x => x.Id, "ProductID").GeneratedBy.Identity();
        Map(x => x.Name, "ProductName");
    }
}

public class OrderHeader {
    public virtual int? Id { get; set; }

    public virtual string Comment { get; set; }

    public virtual IList<OrderDetail> Details { get; set; }
}

public class OrderHeaderMap : ClassMap<OrderHeader> {
    public OrderHeaderMap() {
        Table("OrderHeader");

        Id(x => x.Id, "HeaderID").GeneratedBy.Identity();
        Map(x => x.Comment, "Comment");

        HasMany<OrderDetail>(x => x.Details)
            .KeyColumn("HeaderID")
            .Inverse()
            .Cascade
            .All();
    }
}

public class OrderDetail {
    public virtual OrderHeader OrderHeader { get; set; }

    public virtual Product Product { get; set; }

    public virtual DateTime? CreatedOn { get; set; }

    public override bool Equals(object obj) {
        OrderDetail other = obj as OrderDetail;
        if (other == null) {
            return false;
        } else {
            return this.Product.Id == other.Product.Id && this.OrderHeader.Id == other.OrderHeader.Id;
        }
    }

    public override int GetHashCode() {
        return (OrderHeader.Id.ToString() + "|" + Product.Id.ToString()).GetHashCode();
    }
}

public class OrderDetailMap : ClassMap<OrderDetail> {
    public OrderDetailMap() {
        Table("OrderDetail");

        CompositeId()
            .KeyReference(x => x.Product, "ProductID")
            .KeyReference(x => x.OrderHeader, "HeaderID");

        References<OrderHeader>(x => x.OrderHeader, "HeaderID").ForeignKey().Not.Nullable().Fetch.Join();
        References<Product>(x => x.Product, "ProductID").ForeignKey().Not.Nullable();

        Version(x => x.CreatedOn).Column("CreatedOn").Generated.Always();
    }
}

我還創建了NH Session Provider

public class NHibernateSessionProvider {
    private static ISessionFactory sessionFactory;

    public static ISessionFactory SessionFactory {
        get {
            if (sessionFactory == null) {
                sessionFactory = createSessionFactory();
            }
            return sessionFactory;
        }
    }

    private static ISessionFactory createSessionFactory() {
        return Fluently.Configure()
            .Database(MsSqlConfiguration.MsSql2008.ShowSql()
            .ConnectionString(c => c.FromConnectionStringWithKey("TestDB")))
            .Mappings(m => m.FluentMappings.AddFromAssemblyOf<OrderHeaderMap>())
            .BuildSessionFactory();
    }
}

還創建了NH存儲庫類

public class NHibernateRepository<T, TId> {
        protected ISession session = null;
        protected ITransaction transaction = null;

        public NHibernateRepository() {
            this.session = NHibernateSessionProvider.SessionFactory.OpenSession();
        }

        public void Save(T entity) {
            session.SaveOrUpdate(entity);
        }

        public void AddNew(T entity) {
            session.Save(entity);
        }

        public void BeginTransaction() {
            transaction = session.BeginTransaction();
        }

        public void CommitTransaction() {
            transaction.Commit();
            closeTransaction();
        }

        public void RollbackTransaction() {
            transaction.Rollback();
            closeTransaction();
            closeSession();
        }

        private void closeTransaction() {
            transaction.Dispose();
            transaction = null;
        }

        private void closeSession() {
            session.Close();
            session.Dispose();
            session = null;
        }

        public void Dispose() {
            if (transaction != null) {
                CommitTransaction();
            }

            if (session != null) {
                session.Flush();
                closeSession();
            }
        }
    }

在我的代碼中，我創建了兩種不同的方法來使用composite-id保存這個主/詳細結構。

    private static void method1() {
        NHibernateRepository<Product, int?> repoProduct = new NHibernateRepository<Product, int?>();
        NHibernateRepository<OrderHeader, int?> repo = new NHibernateRepository<OrderHeader, int?>();
        OrderHeader oh = new OrderHeader();
        oh.Comment = "Test Comment " + DateTime.Now.ToString();
        oh.Details = new List<OrderDetail>();
        for (int i = 0; i < 2; i++) {
            oh.Details.Add(new OrderDetail
            {
                OrderHeader = oh,
                Product = repoProduct.GetById(i + 3)
            });
        }

        repo.AddNew(oh);
    }

    private static void method2() {
        NHibernateRepository<OrderHeader, int?> repoHeader = new NHibernateRepository<OrderHeader, int?>();
        OrderHeader oh = new OrderHeader();
        oh.Comment = "Test Comment " + DateTime.Now.ToString();
        repoHeader.Save(oh);

        NHibernateRepository<OrderDetail, int?> repoDetail = new NHibernateRepository<OrderDetail, int?>();
        for (int i = 0; i < 2; i++) {
            OrderDetail od = new OrderDetail
            {
                OrderHeaderId = oh.Id,
                OrderHeader = oh,
                ProductId = i + 3,
                Product = new Product
                {
                    Id = i + 3
                },
            };

            repoDetail.AddNew(od);
        }
    }

但是對於這兩種方法，從不保存OrderDetail表。 我已經打開ShowSql（）來查看在控制台上執行的SQL語句，根本沒有生成SQL來保存OrderDetail表。

我到處做了很多搜索，無法得出明確的結論。

任何人都有一些線索，我需要做什么來保存具有復合ID的實體？

謝謝

哈迪

Answer 1

模型和映射都不正確。

從OrderDetail中刪除OrderHeaderId和ProductId 。

然后，Composite id應該包含OrderHeader和Product作為引用（我認為使用Fluent它的KeyReference而不是KeyProperty ;在XML中它是key-many-to-one而不是key-property ）

然后，添加適當的Cascade設置，如Cole建議的那樣。

樣品用法：

using (var session = GetSessionFromSomewhere())
using (var tx = session.BeginTransaction())
{
    var orderHeader = new OrderHeader();
    ...
    orderHeader.Details.Add(new OrderDetail
                            {
                                OrderHeader = orderHeader;
                                Product = session.Load<Product>(someProductId);
                            });
    session.Save(orderHeader);
    tx.Commit();
}

該塊中的所有內容都是必需的 。

Answer 2

我不認為復合ID是導致問題的原因。 我認為這是您在OrderHeader地圖中映射OrderDetails的方式。

我認為它應該是這樣的：

HasMany<OrderDetail>(x => x.Details).KeyColumn("HeaderID").Inverse().Cascade.AllDeleteOrphan();

編輯：

您應該聽下面的Diego並將您的映射更改為：

public class OrderDetailMap : ClassMap<OrderDetail> {
    public OrderDetailMap() {
        Table("OrderDetail");

        CompositeId()
            .KeyReference(x => x.Product, "ProductID")
            .KeyReference(x => x.OrderHeader, "HeaderID");

        Version(x => x.CreatedOn).Column("CreatedOn").Generated.Always();
    }
}

您上面的OrderDetails映射中的代碼是導致錯誤“此SqlParameterCollection的索引2無效且Count = 2”的原因。

References<OrderHeader>(x => x.OrderHeader, "HeaderID").ForeignKey().Not.Nullable().Fetch.Join();
References<Product>(x => x.Product, "ProductID").ForeignKey().Not.Nullable();

Answer 3

首先，您的OrderDetail映射錯誤：您可能不會多次映射一列。 在這里，您既可以為復合ID分配它，也可以分配多對一。 您的composite-id可以（並且應該）具有2個多對一屬性，而不僅僅是value屬性。

這在您對Diego的答案的最后評論中很明顯，另見IndexOutOfRangeException在NHibernate的深處

其次，你在OrderHeader.Details集合上設置了一個inverse ，如果我沒記錯的話，意味着method1不會在OrderDetail上導致插入