我有一个Parent-Children关系,目前只存在从每个子节点到父节点的引用(子表上有一个外键列)。我想将一个只读IEnumerable属性添加到父级,但我没有这样做。
public class ProjectData : Entity
{
public virtual long Id {get;set;}
private readonly IList<BranchData> _branches = new List<BranchData>();
public virtual IEnumerable<BranchData> Branches
{
get { return _branches.AsReadOnly(); }
}
}
public class BranchData : Entity
{
puplic virtual long Id {get;set;}
public virtual ProjectData ProjectData { get; set; }
}
public class BranchDataMapping : ClassMapping<BranchData>
{
public BranchDataMapping()
{
ManyToOne(x => x.ProjectData, mapper => { });
}
}
public class ProjectDataMapping : ClassMapping<ProjectData>
{
public ProjectDataMapping()
{
Bag(data => data.Branches,
mapper =>
{
mapper.Access(Accessor.ReadOnly);
mapper.Inverse(false);
}, relation => relation.OneToMany());
}
}
表名和列名由约定创建。 当我创建并保存具有父属性集的新BranchDate时,它不会出现在父级的Branches集合中。
我缺少什么设置?
我已阅读Bi-directional NHibernate mapping by code和http://notherdev.blogspot.cz/2012/02/nhibernates-mapping-by-code-summary.html,但仍未能正确设置。
编辑:验证此行为的代码
[Test]
public void CanSaveAndLoadBranch()
{
var session = InMemoryDatabase.GetSession();
var project = new ProjectData {Name = "ratata"};
var branch = new BranchData {ProjectData = project};
using (var tx = session.BeginTransaction())
{
session.Save(project);
session.Save(branch);
tx.Commit();
}
var branches = project.Branches;
//branches are empty
var freshProject = session.Query<ProjectData>().Where(x => x.Id == project.Id).First();
var freshBranches = freshProject.Branches;
//branches are empty here, too
var fetched = session.Query<ProjectData>().Where(x => x.Id == project.Id).FetchMany(x => x.Branches).First();
var fetchedBranches = fetched.Branches;
//branches are empty here, too
var queriedOn = session.Query<ProjectData>().Where(x => x.Branches.Any()).ToList();
//this does return the project, but Branches property is still empty
}
答案 0 :(得分:1)
在操作内存中的数据时,您负责管理关系的两个方面。您可以使用Add
中的ProjectData
方法轻松完成此操作:
public virtual void Add(BranchData branch)
{
branch.ProjectData = this;
Branches.Add(branch);
}
另一方面,NHibernate负责对物体进行适当的保湿和脱水。但是,您没有看到这一点,因为您的查询都发生在同一会话中。请考虑以下代码:
var project = new ProjectData();
session.Save(project);
session.Flush();
var freshProject = session.Get<ProjectData>(project.Id);
if (ReferenceEquals(project, freshProject))
Console.WriteLine("They're the same instance.");
此代码将显示“它们是同一个实例”。该实例的关系设置与初始化时完全相同,无论是否正确。
如果忽略在反面设置关系project.Branches
,NHibernate仍然可以保存它,但在该会话的持续时间内仍然会看起来不一致。如果您关闭会话并打开一个新会话(这可能会对您的内存中测试造成问题),或者只是致电session.Clear()
或session.Evict(project)
,那么您会在project.Branches
时看到数据你再加载它。