如何使用流畅的 nhibernate 自动映射在同一个 table 中引用父实体?
How to reference parent entity in the same table with fluent nhibernate auto mappings?
我正在尝试使用 FluentNHibernate AutoMappings 来创建一个引用其父实体的实体。我能够在 ClassMap<> 的帮助下完成此操作,但现在我想将所有内容移动到 AutoMappings。我有一个具有以下架构的 table:
CREATE TABLE [dbo].[Job]
(
[Id] INT NOT NULL IDENTITY(1,1),
[ParentId] INT NULL,
PRIMARY KEY ([Id]),
CONSTRAINT [FK_Job_Parent] FOREIGN KEY ([ParentId]) REFERENCES [Job]([Id])
)
以及以下 C# 代码:
using FluentNHibernate;
using FluentNHibernate.Automapping;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using FluentNHibernate.Conventions;
using FluentNHibernate.Conventions.Instances;
using System;
using System.Configuration;
namespace NHibernateTest
{
public class Program
{
private static void Main(string[] args)
{
var sessionFactory = Fluently.Configure()
.Database(MsSqlConfiguration.MsSql2008.ConnectionString(ConfigurationManager.ConnectionStrings["Default"].ConnectionString))
.Mappings(m =>
{
m.AutoMappings.Add(
AutoMap.AssemblyOf<Program>(new MappingConfig()).Conventions.Setup(conv =>
{
conv.Add<DefaultReferenceConvention>();
conv.Add<DefaultHasManyConvention>();
conv.Add<SimpleForeignKeyConvention>();
}));
})
.BuildSessionFactory();
using (var session = sessionFactory.OpenSession())
{
using (var tran = session.BeginTransaction())
{
var jobs = session
.QueryOver<Job>()
.List<Job>();
tran.Commit();
}
}
}
}
public class Job
{
public virtual int Id { get; set; }
public virtual Job Parent { get; set; }
}
public class MappingConfig : DefaultAutomappingConfiguration
{
public override bool ShouldMap(Type type)
{
return type == typeof(Job);
}
}
public class SimpleForeignKeyConvention : ForeignKeyConvention
{
protected override string GetKeyName(Member property, Type type)
{
if (property == null)
{
return type.Name + "Id";
}
return property.Name + "Id";
}
}
public class DefaultHasManyConvention : IHasManyConvention
{
public void Apply(IOneToManyCollectionInstance instance)
{
instance.Key.Column(string.Format("{0}{1}", instance.EntityType.Name, "Id"));
instance.LazyLoad();
}
}
public class DefaultReferenceConvention : IReferenceConvention
{
public void Apply(IManyToOneInstance instance)
{
var col = string.Format("{0}Id", instance.Class.Name);
instance.Column(col);
instance.LazyLoad();
}
}
}
我得到:
An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more detail.
Foreign key (FK7D5D63A6AE42E0BA:Job [JobId, ParentId])) must have same number of columns as the referenced primary key (Job [Id])
有没有办法只使用自动映射来做到这一点?
您的 DefaultReferenceConvention
似乎与您的 SimpleForeignKeyConvention
冲突。其中一个使用 属性 name 作为列名的基础,另一个使用 属性 type。出于某种原因,Fluent NH 似乎正在使用其中的 both,并且认为您有一个复合键。
删除 DefaultReferenceConvention
并查看是否可以解决问题。反正也没必要,因为 Fluent NH 默认的外键列命名已经是 {Class.Name}Id
.
Fluent NH 约定非常适合用宽泛的笔触绘制映射,但它们不是更改单个 属性 的列名称的正确工具。在这种情况下,您应该改为定义 IAutoMappingOverride<T>
。
我正在尝试使用 FluentNHibernate AutoMappings 来创建一个引用其父实体的实体。我能够在 ClassMap<> 的帮助下完成此操作,但现在我想将所有内容移动到 AutoMappings。我有一个具有以下架构的 table:
CREATE TABLE [dbo].[Job]
(
[Id] INT NOT NULL IDENTITY(1,1),
[ParentId] INT NULL,
PRIMARY KEY ([Id]),
CONSTRAINT [FK_Job_Parent] FOREIGN KEY ([ParentId]) REFERENCES [Job]([Id])
)
以及以下 C# 代码:
using FluentNHibernate;
using FluentNHibernate.Automapping;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using FluentNHibernate.Conventions;
using FluentNHibernate.Conventions.Instances;
using System;
using System.Configuration;
namespace NHibernateTest
{
public class Program
{
private static void Main(string[] args)
{
var sessionFactory = Fluently.Configure()
.Database(MsSqlConfiguration.MsSql2008.ConnectionString(ConfigurationManager.ConnectionStrings["Default"].ConnectionString))
.Mappings(m =>
{
m.AutoMappings.Add(
AutoMap.AssemblyOf<Program>(new MappingConfig()).Conventions.Setup(conv =>
{
conv.Add<DefaultReferenceConvention>();
conv.Add<DefaultHasManyConvention>();
conv.Add<SimpleForeignKeyConvention>();
}));
})
.BuildSessionFactory();
using (var session = sessionFactory.OpenSession())
{
using (var tran = session.BeginTransaction())
{
var jobs = session
.QueryOver<Job>()
.List<Job>();
tran.Commit();
}
}
}
}
public class Job
{
public virtual int Id { get; set; }
public virtual Job Parent { get; set; }
}
public class MappingConfig : DefaultAutomappingConfiguration
{
public override bool ShouldMap(Type type)
{
return type == typeof(Job);
}
}
public class SimpleForeignKeyConvention : ForeignKeyConvention
{
protected override string GetKeyName(Member property, Type type)
{
if (property == null)
{
return type.Name + "Id";
}
return property.Name + "Id";
}
}
public class DefaultHasManyConvention : IHasManyConvention
{
public void Apply(IOneToManyCollectionInstance instance)
{
instance.Key.Column(string.Format("{0}{1}", instance.EntityType.Name, "Id"));
instance.LazyLoad();
}
}
public class DefaultReferenceConvention : IReferenceConvention
{
public void Apply(IManyToOneInstance instance)
{
var col = string.Format("{0}Id", instance.Class.Name);
instance.Column(col);
instance.LazyLoad();
}
}
}
我得到:
An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more detail.
Foreign key (FK7D5D63A6AE42E0BA:Job [JobId, ParentId])) must have same number of columns as the referenced primary key (Job [Id])
有没有办法只使用自动映射来做到这一点?
您的 DefaultReferenceConvention
似乎与您的 SimpleForeignKeyConvention
冲突。其中一个使用 属性 name 作为列名的基础,另一个使用 属性 type。出于某种原因,Fluent NH 似乎正在使用其中的 both,并且认为您有一个复合键。
删除 DefaultReferenceConvention
并查看是否可以解决问题。反正也没必要,因为 Fluent NH 默认的外键列命名已经是 {Class.Name}Id
.
Fluent NH 约定非常适合用宽泛的笔触绘制映射,但它们不是更改单个 属性 的列名称的正确工具。在这种情况下,您应该改为定义 IAutoMappingOverride<T>
。