流利的NHibernate多对多映射3类 [英] Fluent NHibernate Many-To-Many Mapping with 3 classes
问题描述
pre $公共类classA
{
公共虚拟Int32 Id {获取; }
....
public ICollection< ClassB> ClassesB {get; }
public ICollection< ClassC> ClassesC {get; }
}
public class ClassB
{
public virtual Int32 Id {get; }
....
public ICollection< ClassA> ClassesA {get; }
public ICollection< ClassC> ClassesC {get; }
}
public class ClassC
{
public virtual Int32 Id {get; }
....
public ICollection< ClassA> ClassesA {get; }
public ICollection< ClassB> ClassesB {get; }
}
我用这个代码映射它们:
public class ClassAMap:ClassMap< ClassA>
{
public ClassAMap()
:base()
{
Id(m => m.Id);
...
HasManyToMany (m => m.ClassesB).Cascade.SaveUpdate()。AsSet()。ReadOnlyAccess();
HasManyToMany (m => m.ClassesC).Cascade.SaveUpdate()。AsSet()。ReadOnlyAccess();
}
}
public class ClassBMap:ClassMap< ClassB>
{
public ClassBMap()
:base()
{
Id(m => m.Id);
....
HasManyToMany< ClassA>(m => m.ClassesA).Cascade.SaveUpdate().AsSet()。ReadOnlyAccess();
HasManyToMany (m => m.ClassesC).Cascade.SaveUpdate()。AsSet()。ReadOnlyAccess();
}
}
public class ClassCMap:ClassMap< ClassC>
{
public ClassCMap()
:base()
{
Id(m => m.Id);
....
HasManyToMany< ClassA>(m => m.ClassesA).Cascade.SaveUpdate().AsSet()。ReadOnlyAccess();
HasManyToMany (m => m.ClassesB).Cascade.SaveUpdate()。AsSet()。ReadOnlyAccess();
$ b每个类都有一个集合给另外两个类,不要问为什么,但我需要将其映射到数据库。 Nhibernate生成3个表,其中2个有两个字段,第三个有所有类的3个id字段。第三个表中只有2个字段是主键的一部分。我也尝试为3个关系指定表名,NHibernate只生成一个包含3个字段的表,但是同样只有2个表是Primery Key的一部分。我假设3字段必须是给定这种类型映射的主键的一部分。
问题是我不能将项目添加到集合我也尝试添加项目到另一个类,例如:当我添加ClassB到ClassA也添加ClassA到ClassB维护关系),当我试图保存到数据库时,它会引发一个FOREING KEY异常和所有的字段设置正确。
我的问题是,映射这三个类的最佳方法是什么?我需要做其他事情吗?我是否伪造了一些东西?
解决方案我相信你需要给NH一些关于关系的更多细节。
试试在A的映射和B的映射中写出完整的定义:
$ p $ HasManyToMany(a => a.ClassesB)
.AsSet()
.WithTableName(TBL_A_TO_B)
.WithParentKeyColumn(A_ID)
.WithChildKeyColumn(B_ID)
。 Cascade.All();
First, I'm using NHibernate 3.2 and FluentNHibernate 1.3. I have 3 clasess:
public class ClassA
{
public virtual Int32 Id{ get; }
....
public ICollection<ClassB> ClassesB { get; }
public ICollection<ClassC> ClassesC { get; }
}
public class ClassB
{
public virtual Int32 Id{ get; }
....
public ICollection<ClassA> ClassesA { get; }
public ICollection<ClassC> ClassesC { get; }
}
public class ClassC
{
public virtual Int32 Id{ get; }
....
public ICollection<ClassA> ClassesA { get; }
public ICollection<ClassB> ClassesB { get; }
}
I mapped them with this code:
public class ClassAMap : ClassMap<ClassA>
{
public ClassAMap()
: base()
{
Id(m => m.Id);
....
HasManyToMany<ClassB>(m => m.ClassesB).Cascade.SaveUpdate().AsSet().ReadOnlyAccess();
HasManyToMany<ClassC>(m => m.ClassesC).Cascade.SaveUpdate().AsSet().ReadOnlyAccess();
}
}
public class ClassBMap : ClassMap<ClassB>
{
public ClassBMap()
: base()
{
Id(m => m.Id);
....
HasManyToMany<ClassA>(m => m.ClassesA).Cascade.SaveUpdate().AsSet().ReadOnlyAccess();
HasManyToMany<ClassC>(m => m.ClassesC).Cascade.SaveUpdate().AsSet().ReadOnlyAccess();
}
}
public class ClassCMap : ClassMap<ClassC>
{
public ClassCMap()
: base()
{
Id(m => m.Id);
....
HasManyToMany<ClassA>(m => m.ClassesA).Cascade.SaveUpdate().AsSet().ReadOnlyAccess();
HasManyToMany<ClassB>(m => m.ClassesB).Cascade.SaveUpdate().AsSet().ReadOnlyAccess();
}
}
Each class has a collection to the other 2 classes, don't ask why, but I need to map this to a database. Nhibernate generates 3 tables, 2 of them with 2 fields and the third one with the 3 id fields from all the classes, o this third table just 2 fields are part of a Primary Key. I also tryed to asign the table name for the 3 relationships, and NHibernate generates just one table with the 3 fields, but again, only 2 of them are part of the Primery Key. I'm assuming that the 3 field must be part of the primary key given this type of mapping.
The problem is that I can't add items to either collection (I also tried adding the item to the other side class, eg: when I add ClassB to ClassA also add ClassA to ClassB to maintaing the relationship), when I tried to save to database, It throws a FOREING KEY exception and all of the field are set correctly.
My question is, what is the best way to map these three classes? Do I need to do anything else? Am I forgeting something?
I believe you need to give NH some more details about the relations.
Try Writing the full definition in A's mapping and B's mapping:
HasManyToMany(a => a.ClassesB)
.AsSet()
.WithTableName("TBL_A_TO_B")
.WithParentKeyColumn("A_ID")
.WithChildKeyColumn("B_ID")
.Cascade.All();
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