11

我正在尝试学习NHibernate 3.2 built-in mapping by code api不是FluentNHibernate,也不是 xml)。你能帮我映射这些实体之间的多对多关系吗?

public class Post {
    public virtual Id { get; set; }
    public IList<Tag> Tags { get; set; }
}

public class Tag {
    public virtual Id { get; set; }
    public IList<Post> Posts { get; set; }
}

我的主要关键策略是:

Id( 
    t => t.Id, 
    t => { 
        t.Generator(Generators.HighLow, g => g.Params(new { max_low = 100 })); 
        t.Column(typeof(TEntity).Name + "Id"); 
    });

我试试这个:

// TagMap : ClassMapping<Tag>
Bag(t => t.Posts, bag => {
    bag.Inverse(true);
    bag.Table("TagsPosts");
    bag.Cascade(Cascade.DeleteOrphans);
}, t => t.ManyToMany(c => {
    c.Column("PostId");
    c.Lazy(LazyRelation.Proxy);
})); 

// PostMap : ClassMapping<Post>
Bag(t => t.Tags, bag => {
    bag.Table("TagsPosts");
    bag.Cascade(Cascade.DeleteOrphans);
}, t => t.ManyToMany(c => {
    c.Column("TagId");
    c.Lazy(LazyRelation.Proxy);
}));

但它不起作用。

4

2 回答 2

31
// Post Map
Bag(x => x.Tags, collectionMapping =>
                {
                    collectionMapping.Table("TagPosts");
                    collectionMapping.Cascade(Cascade.None);
                    collectionMapping.Key(k => k.Column("PostID"));
                },
                    map => map.ManyToMany(p => p.Column("TagID")));

// Tag Map
Bag(x => x.Posts, collectionMapping =>
                                         {
                                             collectionMapping.Table("TagPosts");
                                             collectionMapping.Cascade(Cascade.None);
                                             collectionMapping.Key(k => k.Column("TagID"));
                                         },
                map => map.ManyToMany(p => p.Column("PostID")));
于 2012-03-05T23:06:35.837 回答
1

我认为您需要设置密钥来告诉 nhibernate 它需要检查多对多表上的哪一列,如下所示:

// TagMap
bag.Key(k => k.Column("TagId"));

// PostMap
bag.Key(k => k.Column("PostId"));
于 2012-03-05T20:27:59.987 回答