分享程序员开发的那些事...
更新时间：2022-10-29 23:18:58
有两种基本方法如何映射在NH双向one-to-one关联。比方说，类看起来是这样的：
公共类设置
{
公共虚拟的Guid标识{得到;组; }
公共虚拟学生学生{搞定;组; }
}
公共类学生
{
公共虚拟的Guid标识{搞定;组; }
公共虚拟设定设定{搞定;组; }
}
设置类是在协会主（聚合根）。这是相当不寻常，但是它依赖于问题域...
联合
公共SettingMap（）
{
ID（X => x.Id）.GeneratedBy.Guid（）;
HasOne（X => x.Student）.Cascade.All（）;
}
公共StudentMap（）
{
ID（X => x.Id）.GeneratedBy.Foreign（设置）;
HasOne（X => x.Setting）.Constrained（）;
}
和新设置的实例应该保存：
VAR值=新设置（）;
setting.Student =新学生（）;
setting.Student.Name =student1;
setting.Student.Setting =设置;
setting.Name =设置1;
session.Save（设置）;
外键关联
公共SettingMap（）
{
ID（X => x.Id）.GeneratedBy.Guid（）;
引用（X => x.Student）.Unique（）Cascade.All（）。
}
公共StudentMap（）
{
ID（X => x.Id）.GeneratedBy.Guid（）;
HasOne（X => x.Setting）.Cascade.All（）PropertyRef（学生）。
}
联合接近您的解决方案。主键协会应当你绝对相信，该协会将永远一对单只使用。需要注意的是AllDeleteOrphan级联不支持单对单的NH
编辑：欲了解更多详情，请参见：
http://fabiomaulo.blogspot.com/2010/03/conform -mapping一对one.html
的 http://ayende.com/blog/3960/nhibernate-mapping-one-to-one
How do I do this I am trying to make a one to one mapping.
public class Setting
{
public virtual Guid StudentId { get; set; }
public virtual DateFilters TaskFilterOption { get; set; }
public virtual string TimeZoneId { get; set; }
public virtual string TimeZoneName { get; set; }
public virtual DateTime EndOfTerm { get; set; }
public virtual Student Student { get; set; }
}
// class map
public SettingMap()
{
/// Id(Reveal.Member<Setting>("StudentId")).GeneratedBy.Foreign("StudentId");
//Id(x => x.StudentId);
Map(x => x.TaskFilterOption).Default(DateFilters.All.ToString()).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.TimeZoneId).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.TimeZoneName).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.EndOfTerm).Default("5/21/2011").Not.Nullable();
HasOne(x => x.Student);
}
// student map
public class StudentMap : ClassMap<Student>
{
public StudentMap()
{
Id(x => x.StudentId);
HasOne(x => x.Setting).Cascade.All();
}
}
public class Student
{
public virtual Guid StudentId { get; private set; }
public virtual Setting Setting { get; set; }
}
Now every time I try to create a settings object and save it to the database it crashes.
Setting setting = new Setting
{
TimeZoneId = viewModel.SelectedTimeZone,
TimeZoneName = info.DisplayName,
EndOfTerm = DateTime.UtcNow.AddDays(-1),
Student = student
};
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Settings_Students". The conflict occurred in database "Database", table "dbo.Students", column 'StudentId'.
The statement has been terminated.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Data.SqlClient.SqlException: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Settings_Students". The conflict occurred in database "Database", table "dbo.Students", column 'StudentId'.
The statement has been terminated.
What am I missing?
Edit
public class StudentMap : ClassMap<Student>
{
public StudentMap()
{
Id(x => x.StudentId).GeneratedBy.Guid();
HasOne(x => x.Setting).PropertyRef("Student").Cascade.All();
}
}
public class SettingMap : ClassMap<Setting>
{
public SettingMap()
{
Id(x => x.StudentId).GeneratedBy.Guid();
Map(x => x.TaskFilterOption).Default(DateFilters.All.ToString()).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.TimeZoneId).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.TimeZoneName).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.EndOfTerm).Default("5/21/2011").Not.Nullable();
References(x => x.Student).Unique();
}
}
// try 1
Setting setting = new Setting
{
TimeZoneId = viewModel.SelectedTimeZone,
TimeZoneName = info.DisplayName,
EndOfTerm = DateTime.UtcNow.AddDays(-1),
Student = student
};
studentRepo.SaveSettings(setting);
studentRepo.Commit();
// try 2
Setting setting = new Setting
{
TimeZoneId = viewModel.SelectedTimeZone,
TimeZoneName = info.DisplayName,
EndOfTerm = DateTime.UtcNow.AddDays(-1),
Student = student
};
student.Setting = setting
studentRepo.CreateStudent(student);
studentRepo.Commit();
I get these error for both ways
Invalid index 5 for this SqlParameterCollection with Count=5. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.IndexOutOfRangeException: Invalid index 5 for this SqlParameterCollection with Count=5.
Source Error:
Line 76: using (ITransaction transaction = session.BeginTransaction()) Line 77: { Line 78: transaction.Commit(); Line 79: } Line 80: }
There are two basic ways how to map bidirectional one-to-one association in NH. Let's say the classes look like this:
public class Setting
{
public virtual Guid Id { get; set; }
public virtual Student Student { get; set; }
}
public class Student
{
public virtual Guid Id { get; set; }
public virtual Setting Setting { get; set; }
}
Setting class is a master in the association ("aggregate root"). It is quite unusual but it depends on problem domain...
Primary key association
public SettingMap()
{
Id(x => x.Id).GeneratedBy.Guid();
HasOne(x => x.Student).Cascade.All();
}
public StudentMap()
{
Id(x => x.Id).GeneratedBy.Foreign("Setting");
HasOne(x => x.Setting).Constrained();
}
and a new setting instance should be stored:
var setting = new Setting();
setting.Student = new Student();
setting.Student.Name = "student1";
setting.Student.Setting = setting;
setting.Name = "setting1";
session.Save(setting);
Foreign key association
public SettingMap()
{
Id(x => x.Id).GeneratedBy.Guid();
References(x => x.Student).Unique().Cascade.All();
}
public StudentMap()
{
Id(x => x.Id).GeneratedBy.Guid();
HasOne(x => x.Setting).Cascade.All().PropertyRef("Student");
}
Primary key association is close to your solution. Primary key association should be used only when you are absolutely sure that the association will be always one-to-one. Note that AllDeleteOrphan cascade is not supported for one-to-one in NH.
EDIT: For more details see:
http://fabiomaulo.blogspot.com/2010/03/conform-mapping-one-to-one.html