NHibernate QueryOver多重连接别名，只有第一个生成连接

Question

我试图连接使用JoinAlias的几个实体，并且无法弄清楚如何获取多个连接。下面的代码导致SQL错误：

[TestMethod] 
public void TestAliases() 
{ 
    App_Start.NHibernateProfilerBootstrapper.PreStart(); 

    var type = new ShirtStyleType {Id = 1}; 
    var style = new ShirtStyle {Id = 1, ShirtStyleType = type}; 
    var shirt = new Shirt {Id = 1}; 
    var shirtStyle = new ShirtShirtStyle {Shirt = shirt, ShirtStyle = style}; 
    shirt.ShirtStyles = new[] {shirtStyle}; 

    using (Session.BeginTransaction()) 
     Session.Save(shirt); 

    Session.Clear(); 

    using (Session.BeginTransaction()) 
    { 
     Shirt shirtAlias = null; 
     ShirtShirtStyle shirtStylesAlias = null; 
     ShirtStyle shirtStyleAlias = null; 
     ShirtStyleType shirtStyleTypeAlias = null; 

     var query = Session.QueryOver<Shirt>(() => shirtAlias) 
      .JoinAlias(() => shirtAlias.ShirtStyles,() => shirtStylesAlias) 
      .JoinAlias(() => shirtStylesAlias.ShirtStyle,() => shirtStyleAlias) 
      .JoinAlias(() => shirtStyleAlias.ShirtStyleType,() => shirtStyleTypeAlias) 
      .Where(() => shirtStyleTypeAlias.Id == 1) 
      .List(); 
    } 
} 

错误：

ERROR: 
SQLite error 
no such column: shirtstyle3_.Id 

导致错误的SQL：

SELECT this_.Id    as Id0_1_, 
     shirtstyle1_.Shirt  as Shirt1_0_, 
     shirtstyle1_.ShirtStyle as ShirtStyle1_0_ 
FROM "Shirt" this_ 
     inner join "ShirtShirtStyle" shirtstyle1_ 
     on this_.Id = shirtstyle1_.Shirt_id 
WHERE shirtstyle3_.Id = 1 /* @p0 */ 

这是非常明显的看出为什么错误发生 - 查询缺少连接，特别是除“ShirtShirtStyle”之外的每个连接。从我对JoinAlias的理解，我提供的代码应该加入必要的表格，但它不是，我不明白为什么。在这种情况下，有什么需要让JoinAlias工作？

我为这个测试创建的实体和映射如下，以防它们与它们的映射方式有关。

实体：

public class Shirt 
{ 
    public virtual int Id { get; set; } 
    public virtual IList<ShirtShirtStyle> ShirtStyles { get; set; } 
} 

public class ShirtShirtStyle 
{ 
    public virtual Shirt Shirt { get; set; } 
    public virtual ShirtStyle ShirtStyle { get; set; } 

    protected bool Equals(ShirtShirtStyle other) 
    { 
     return Equals(Shirt, other.Shirt) && Equals(ShirtStyle, other.ShirtStyle); 
    } 

    public override bool Equals(object obj) 
    { 
     if (ReferenceEquals(null, obj)) return false; 
     if (ReferenceEquals(this, obj)) return true; 
     if (obj.GetType() != this.GetType()) return false; 
     return Equals((ShirtShirtStyle) obj); 
    } 

    public override int GetHashCode() 
    { 
     unchecked 
     { 
      return ((Shirt != null ? Shirt.GetHashCode() : 0)*397)^(ShirtStyle != null ? ShirtStyle.GetHashCode() : 0); 
     } 
    } 
    } 

    public class ShirtStyle 
    { 
     public virtual int Id { get; set; } 
     public virtual ShirtStyleType ShirtStyleType { get; set; } 
    } 

    public class ShirtStyleType 
    { 
     public virtual int Id { get; set; } 
    } 

地图：

public class ShirtMap : ClassMap<Shirt> 
{ 
    public ShirtMap() 
    { 
     Id(x => x.Id).GeneratedBy.Assigned(); 
     HasMany(x => x.ShirtStyles); 
    } 
} 

public sealed class ShirtShirtStyleMap : ClassMap<ShirtShirtStyle> 
{ 
    public ShirtShirtStyleMap() 
    { 
     CompositeId() 
      .KeyReference(x => x.Shirt) 
      .KeyReference(x => x.ShirtStyle); 
    } 
} 

public sealed class ShirtStyleMap : ClassMap<ShirtStyle> 
{ 
    public ShirtStyleMap() 
    { 
     Id(x => x.Id).GeneratedBy.Assigned(); 
     References(x => x.ShirtStyleType); 
    } 
} 

public sealed class ShirtStyleTypeMap : ClassMap<ShirtStyleType> 
{ 
    public ShirtStyleTypeMap() 
    { 
     Id(x => x.Id).GeneratedBy.Assigned(); 
    } 
} 

Answer 1

那么这个查询似乎只是按预期 - 这个问题看起来是与功能NHibernate。即使引用是通过.KeyReference在复合实体上指定的，您需要明确地在映射中根据https://stackoverflow.com/a/10995486/981205重新指定它们。不知道这是一个错误还是预期的行为。