以下Fluent NHibernate映射有什么问题？

Question

我有3张桌子(多对多关系)

1. 资源{ResourceId,Description}
2. 角色{RoleId,Description}
3. 权限{ResourceId,RoleId}

我试图在fluent-nHibernate中映射上面的表格.这就是我想要做的.

var aResource = session.Get<Resource>(1); // 2 Roles associated (Role 1 and 2)
var aRole = session.Get<Role>(1);
aResource.Remove(aRole); // I try to delete just 1 role from permission.

但是这里生成的sql是(这是错误的)

Delete from Permission where ResourceId = 1
Insert into Permission (ResourceId, RoleId) values (1, 2);

而不是(正确的方式)

    Delete from Permission where ResourceId = 1 and RoleId = 1

为什么nHibernate表现得像这样？映射有什么问题？我甚至尝试使用Set而不是IList.这是完整的代码.

实体

public class Resource
{
    public virtual string Description { get; set; }
    public virtual int ResourceId { get; set; }
    public virtual IList<Role> Roles { get; set; }

    public Resource()
    {
        Roles = new List<Role>();
    }
}

public class Role
{
    public virtual string Description { get; set; }
    public virtual int RoleId { get; set; }
    public virtual IList<Resource> Resources { get; set; }

    public Role()
    {
        Resources = new List<Resource>();
    }
}

在此映射

// Mapping ..
public class ResourceMap : ClassMap<Resource>
{
    public ResourceMap()
    {
        Id(x => x.ResourceId);
        Map(x => x.Description);
        HasManyToMany(x => x.Roles).Table("Permission");
    }
}

public class RoleMap : ClassMap<Role>
{
    public RoleMap()
    {
        Id(x => x.RoleId);
        Map(x => x.Description);
        HasManyToMany(x => x.Resources).Table("Permission");
    }
}

程序

    static void Main(string[] args)
    {
        var factory = CreateSessionFactory();
        using (var session = factory.OpenSession())
        {
            using (var tran = session.BeginTransaction())
            {
                var aResource = session.Get<Resource>(1);
                var aRole = session.Get<Role>(1);
                aResource.Remove(aRole);
                session.Save(a);
                session.Flush(); 
                tran.Commit();
            }
        }
    }
    private static ISessionFactory CreateSessionFactory()
    {
        return Fluently.Configure()
            .Database(MsSqlConfiguration.MsSql2008
            .ConnectionString("server=(local);database=Store;Integrated Security=SSPI"))
            .Mappings(m => 
                m.FluentMappings.AddFromAssemblyOf<Program>()
                .Conventions.Add<CustomForeignKeyConvention>())
            .BuildSessionFactory();
    }

    public class CustomForeignKeyConvention : ForeignKeyConvention
    {
        protected override string GetKeyName(FluentNHibernate.Member property, Type type)
        {
            return property == null ? type.Name + "Id" : property.Name + "Id";
        }
    }

谢谢,阿什拉夫.

Answer 1

nHibernate认为所有关系都是双向的,直到你声明父/子.所以你需要"反向".如果没有这个,它需要两个步骤:"删除"全部和"重新创建"新值,特别是"包"类型(默认).对于多对多,改变实体集合类型(HashSet的/套)不会影响到"袋".它仅适用于的hasMany的映射.你需要在地图中特别说"AsSet".(IList/ICollection)映射到"Bag".如果你想要List,你需要在地图中使用它"AsList".但List需要表中的附加索引列.

// Mapping .. 
public class ResourceMap : ClassMap<Resource> 
{ 
    public ResourceMap() 
    { 
        Id(x => x.ResourceId); 
        Map(x => x.Description); 
        HasManyToMany(x => x.Roles).AsSet().Inverse().Table("Permission");
    } 
} 

public class RoleMap : ClassMap<Role> 
{ 
    public RoleMap() 
    { 
        Id(x => x.RoleId); 
        Map(x => x.Description); 
        HasManyToMany(x => x.Resources).AsSet().Cascade.SaveUpdate().Table("Permission");
    } 
} 

另外,我会将Fetch.Select().LazyLoad()用于lazyload.