nhibernate - 流利的 NHibernate 复合 ID 到映射类

Question

我想弄清楚如何使用 CompositeId 来映射另一个类。这是一个测试用例:

表:

TestParent:
  TestParentId (PK)
  FavoriteColor

TestChild:
  TestParentId (PK)
  ChildName (PK)
  Age

C#中的类:

public class TestParent
{
    public TestParent()
    {
        TestChildList = new List<TestChild>();
    }

    public virtual int TestParentId { get; set; }
    public virtual string FavoriteColor { get; set; }
    public virtual IList<TestChild> TestChildList { get; set; }
}

public class TestChild
{
    public virtual TestParent Parent { get; set; }
    public virtual string ChildName { get; set; }
    public virtual int Age { get; set; }

    public override int GetHashCode()
    {
        return Parent.GetHashCode() ^ ChildName.GetHashCode();
    }

    public override bool Equals(object obj)
    {
        if (obj is TestChild)
        {
            var toCompare = obj as TestChild;
            return this.GetHashCode() != toCompare.GetHashCode();
        }
        return false;
    }
}

Fluent NHibernate 映射:

public class TestParentMap : ClassMap<TestParent>
{
    public TestParentMap()
    {
        Table("TestParent");
        Id(x => x.TestParentId).Column("TestParentId").GeneratedBy.Native();
        Map(x => x.FavoriteColor);

        HasMany(x => x.TestChildList).KeyColumn("TestParentId").Inverse().Cascade.None();
    }
}

public class TestChildMap : ClassMap<TestChild>
{
    public TestChildMap()
    {
        Table("TestChild");
        CompositeId()
            .KeyProperty(x => x.ChildName, "ChildName")
            .KeyReference(x => x.Parent, "TestParentId");

        Map(x => x.Age);
        References(x => x.Parent, "TestParentId");  /**  breaks insert **/
    }
}

当我尝试添加新记录时，出现此错误:

System.ArgumentOutOfRangeException : Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

我知道这个错误是由于在 CompositeId 和 References 调用中映射了 TestParentId 列。但是，在根据 TestParentId 查询 TestChild 时，删除 References 调用会导致另一个错误。

这是执行查询的代码:

var session = _sessionBuilder.GetSession();
using (var tx = session.BeginTransaction())
{
    // create parent
    var p = new TestParent() { FavoriteColor = "Red" };
    session.Save(p);

    // creat child
    var c = new TestChild()
                {
                    ChildName = "First child",
                    Parent = p,
                    Age = 4
                };
    session.Save(c);  // breaks with References call in TestChildMap 

    tx.Commit();
}

// breaks without the References call in TestChildMap 
var children = _sessionBuilder.GetSession().CreateCriteria<TestChild>()
    .CreateAlias("Parent", "p")
    .Add(Restrictions.Eq("p.TestParentId", 1))
    .List<TestChild>();

关于如何为此场景创建复合键的任何想法？

Answer 1

我找到了一个更好的解决方案，允许查询和插入。关键是更新 TestChild 的映射以不插入记录。新 map 是:

public class TestChildMap : ClassMap<TestChild>
{
    public TestChildMap()
    {
        Table("TestChild");
        CompositeId()
            .KeyProperty(x => x.ChildName, "ChildName")
            .KeyReference(x => x.Parent, "TestParentId");

        Map(x => x.Age);
        References(x => x.Parent, "TestParentId")
            .Not.Insert();  //  will avoid "Index was out of range" error on insert
    }
}