我的数据库中有两个表Question和LanguageCode
以下是问题表的结构:
QuestionId int
Text varchar(100)
LanguageCode uniqueidentifier
以下是LanguageCode表的结构:
Id uniqueidentifier
Name varchar(20)
现在我想使用NHibernate来映射这两个实体,为此我创建了Question&LanguageCode实体:
问题实体:
public class Question
{
public Question()
{
}
public virtual int Id { get; set; }
public virtual string Text { get; set; }
public virtual LanguageCode LanguageCode { get; set; }
}
语言代码实体:
public class LanguageCode
{
public LanguageCode()
{
}
public virtual Guid Id { get; set; }
public virtual string Name { get; set; }
}
以下是这两个实体类的映射
问题地图:
internal class QuestionMap : ClassMap<Question>
{
public QuestionMap()
{
ReadOnly();
Table("Question");
Id(x => x.Id).Column("Id").GeneratedBy.Assigned();
Map(x => x.Text);
HasOne(x => x.LanguageCode);
}
}
语言代码映射:
internal class LanguageCodeMap:ClassMap<LanguageCode>
{
public LanguageCodeMap()
{
ReadOnly();
Table("LanguageCode");
Id(x => x.Id).Column("Id").GeneratedBy.Assigned();
Map(x => x.Name);
}
}
现在执行以下代码:
LanguageCode languageCodeAlias = null;
Question question = null;
var res = session.QueryOver(()=>question)
.JoinAlias(() => question.LanguageCode, () => languageCodeAlias)
.WhereRestrictionOn(x=>x.Id).IsIn(questionIds).List();
我得到一个SQLException,下面是在执行时创建的查询:
SELECT this_.Id as Id1_1_, this_.Text as Text2_1_1_,
this_.LanguageCode_id as Language5_1_1_,
languageco1_.Id as Id0_0_, languageco1_.Name as Name0_0_ FROM
[Question] this_ inner join [LanguageCode] languageco1_ on
this_.LanguageCode_id=languageco1_.Id WHERE this_.Id in (157827)
很明显,它使用的不是表名LanguageCode而是LanguageCode_id,我不知道如何解决这个问题。所以请帮我解决这个问题,如果需要更多的细节,请告诉我。
我将使用正确的引用而不是HasOne
。
internal class QuestionMap: ClassMap<Question>
{
public QuestionMap()
{
ReadOnly();
Table("Question");
Id(x => x.Id).Column("Id").GeneratedBy.Assigned();
Map(x => x.Text);
References(x => x.LanguageCode).Column("LanguageCode");
}
}
HasOne
适用于一对一的特殊情况,我希望您能使用相同的LanguageCode提出许多问题。
我通过添加以下类找到了解决方案:
public class CustomForeignKeyConvention : IReferenceConvention
{
public void Apply(IManyToOneInstance instance)
{
instance.Column(instance.Class.Name);
}
}
并在SessionFactory中配置:
Fluently.Configure()
.Database(ConfigureDb())
.Mappings(m=>m.AutoMappings.Add(AutoMap.AssemblyOf<QuestionMap>(cfg)
.Conventions.AddFromAssemblyOf<CustomForeignKeyConvention>()))
.BuildSessionFactory();
如果列名类似于"columnname_abc",那么我们可以更改
instance.Column(instance.Class.Name)到实例。列(instance.Class.Name+"_abc");