将外键映射为主键 Fluent NHibernate答案

【问题标题】：Mapping Foreign Key as Primary Key Fluent NHibernate将外键映射为主键 Fluent NHibernate
【发布时间】：2014-05-26 16:28:27
【问题描述】：

我有如下表格场景：

User
    - Id       (PK)
    - Username 

Advert
    - Id    (PK)
    - Title

AdvertPhoto
    - Advert (PK) (Also a FK for Advert table)
    - Image

Bid
    - Advert (PK) (Also a FK for Advert table)
    - User   (PK) (Also a FK for User table)
    - Value

好的，我正在尝试使用以下代码映射这些实体：

public class AdvertMapping : BaseMapping<Advert> {
    public AdvertMapping() : base("Advert") {
        Id(model => model.Id).Not.Nullable().Unique().GeneratedBy.Identity();
        Map(model => model.Title).Not.Nullable().Length(100).Insert().Update();
    }
}

public class AdvertPhotoMapping : BaseMapping<Advert> {
    public AdvertPhotoMapping() : base("AdvertPhoto") {
        Id(model => model.Advert)
            .Column("Id")
            .GeneratedBy.Foreign("Advert");

        Map(model => model.Description).Nullable();
        Map(model => model.Photo).CustomSqlType("image").Not.Nullable();
        References(model => model.Advert, "Advert").Not.Nullable().Not.LazyLoad();
    }
}

public class BidMapping { //: BaseMapping<Bid> {
    public BidMapping() : base("Bid") {
        Id(model => model.Advert, "Advert").GeneratedBy.Foreign("Advert");
            CompositeId()
                .KeyReference(model => model.Advert, "Advert")
                .KeyReference(model => model.User, "User");

            Map(model => model.Value).Not.Nullable().Insert().Update();
            References(model => model.Advert, "Advert").Not.Nullable().Not.LazyLoad();
    }
}

好的，当 Fluent NHibernate 尝试引用 AdvertPhotoMapping 类中的 Advert 列并且我不知道 BidMapping CompositeId 是否正确映射时，我遇到了异常。

我得到的例外是：

{"Could not determine type for: SYB.Engine.Entities.Advert, SYB.Engine, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null, for columns: NHibernate.Mapping.Column(Advert)"}

我做错了什么？谢谢大家！

【问题讨论】：

标签： c# fluent-nhibernate composite-id

【解决方案1】：

通常这就是我映射一对一关系的方式：

public class AdvertPhotoMapping : BaseMapping<Advert> {
    public AdvertPhotoMapping() : base("AdvertPhoto") {
        Id(model => model.Advert)
            .Column("Id")
            .GeneratedBy.Foreign("Advert");

        Map(model => model.Description).Nullable();
        Map(model => model.Photo).CustomSqlType("image").Not.Nullable();
        HasOne(model => model.Advert).Constrained();
    }
}

public class AdvertMapping : BaseMapping<Advert> {
    public AdvertMapping() : base("Advert") {
        Id(model => model.Id).Not.Nullable().Unique().GeneratedBy.Identity();
        Map(model => model.Title).Not.Nullable().Length(100).Insert().Update();
        HasOne(x => x.AdvertPhoto).Cascade.All();
    }
}

您也不需要BidMapping 中的引用映射。它应该是这样的：

CompositeId()
    .KeyReference(model => model.Advert, "Advert")
    .KeyReference(model => model.User, "User");

     Map(model => model.Value).Not.Nullable().Insert().Update();

【讨论】：