[英]Creating multiple bi-directial one-to-many associations with Fluent NHibernate automapping
我對NHibernate和.NET框架還很陌生。
我想映射我的Project類,該類具有一對多關系Subproject和ProjectTask類。
public class Project : ProjectItem
{
public virtual IList<Subproject> Subprojects { get; set; }
public virtual IList<ProjectTask> Tasks { get; set; }
[NotNull]
public virtual ProjectStatus Status { get; set; }
public Project()
{
Subprojects = new List<Subproject>();
Tasks = new List<ProjectTask>();
Status = new ProjectStatus();
}
public virtual void AddSubProject(Subproject subproject)
{
subproject.Project = this;
Subprojects.Add(subproject);
}
public virtual void RemoveSubProject(Subproject subproject)
{
Subprojects.Remove(subproject);
}
public virtual void AddTask(ProjectTask task)
{
task.Project = this;
Tasks.Add(task);
}
public virtual void RemoveTask(ProjectTask task)
{
Tasks.Remove(task);
}
}
public class ProjectTask : ProjectItemTask
{
[NotNull]
public virtual Project Project { get; set; }
}
public class Subproject : ProjectItem
{
[NotNull]
public virtual Project Project { get; set; }
}
我的實體從抽象基類繼承Id屬性。
我使用自動映射重寫來重新定義我的映射:
public class ProjectMappingOverride : IAutoMappingOverride<Project>
{
public void Override(AutoMapping<Project> mapping)
{
mapping.HasMany<Subproject>(x => x.Subprojects)
.Cascade.All()
.Inverse()
.Not.LazyLoad()
.AsBag();
mapping.HasMany<ProjectTask>(x => x.Tasks)
.Cascade.All()
.Inverse()
.Not.LazyLoad()
.AsBag();
mapping.HasOne<ProjectStatus>(x => x.Status)
.Cascade.All()
.Not.LazyLoad();
}
}
public class SubprojectMappingOverride : IAutoMappingOverride<Subproject>
{
public void Override(AutoMapping<Subproject> mapping)
{
mapping.References<Project>(x => x.Project)
.ForeignKey("ProjectId");
}
}
public class ProjectTaskMappingOverride : IAutoMappingOverride<ProjectTask>
{
public void Override(AutoMapping<ProjectTask> mapping)
{
mapping.References<Project>(x => x.Project)
.ForeignKey("ProjectId");
}
}
當我僅將關聯與Subproject類映射時,一切正常,並且Project.Subprojects中Subproject類的所有實例都將正確存儲到數據庫中。 當我對ProjectTask類使用第二個替代時,出現以下異常:
---> NHibernate.HibernateException:數據庫中已經有一個名為“ ProjectId”的對象。 無法創建約束。 請參閱先前的錯誤。
---> System.Data.SqlClient.SqlException:數據庫中已經有一個名為“ ProjectId”的對象。
有人知道,為什么會這樣嗎?
您應該使用Column
而不是ForeignKey
映射項目引用
mapping.References<Project>(x => x.Project)
.Column("ProjectId");
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