映射抽象类和子类时NHibernate DuplicateMappingException

发布于 2024-09-05 21:07:02 字数 1377 浏览 5 评论 0原文

我有一个抽象类及其子类，我想使用 NHibernate 将其映射到我的数据库。我正在使用 Fluent 以及如何进行映射。但是当我添加子类的映射时，映射时会抛出 NHibernate.DuplicateMappingException 。为什么？

这是我的（简化的）类：

public abstract class FieldValue
{
    public int Id { get; set; }
    public abstract object Value { get; set; }
}

public class StringFieldValue : FieldValue
{        
    public string ValueAsString { get; set; }
    public override object Value
    {
        get
        {
            return ValueAsString; 
        } 
        set
        {
            ValueAsString = (string)value; 
        }
    } 
}

和映射：

public class FieldValueMapping : ClassMap<FieldValue>
{
    public FieldValueMapping()
    {
        Id(m => m.Id).GeneratedBy.HiLo("1");
        // DiscriminateSubClassesOnColumn("type"); 
    }
}

public class StringValueMapping : SubclassMap<StringFieldValue>
{
    public StringValueMapping()
    { 
        Map(m => m.ValueAsString).Length(100);
    }
}

和例外：

> NHibernate.MappingException : Could not compile the mapping document: (XmlDocument)
  ----> NHibernate.DuplicateMappingException : Duplicate class/entity mapping NamespacePath.StringFieldValue

有什么想法吗？

原文

I have an abstract class and subclasses of this, and I want to map this to my database using NHibernate. I'm using Fluent and how to do the mapping. But when I add the mapping of the subclass an NHibernate.DuplicateMappingException is thrown when it is mapping. Why?

Here are my (simplified) classes:

public abstract class FieldValue
{
    public int Id { get; set; }
    public abstract object Value { get; set; }
}

public class StringFieldValue : FieldValue
{        
    public string ValueAsString { get; set; }
    public override object Value
    {
        get
        {
            return ValueAsString; 
        } 
        set
        {
            ValueAsString = (string)value; 
        }
    } 
}

And the mappings:

public class FieldValueMapping : ClassMap<FieldValue>
{
    public FieldValueMapping()
    {
        Id(m => m.Id).GeneratedBy.HiLo("1");
        // DiscriminateSubClassesOnColumn("type"); 
    }
}

public class StringValueMapping : SubclassMap<StringFieldValue>
{
    public StringValueMapping()
    { 
        Map(m => m.ValueAsString).Length(100);
    }
}

And the exception:

> NHibernate.MappingException : Could not compile the mapping document: (XmlDocument)
  ----> NHibernate.DuplicateMappingException : Duplicate class/entity mapping NamespacePath.StringFieldValue

Any ideas?

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海风掠过北极光 2024-09-12 21:07:02

发现了问题。事实证明，我确实在用于配置数据库的 PersistenceModel 中多次引用了同一个程序集：

public class MappingsPersistenceModel : PersistenceModel
{
    public MappingsPersistenceModel()
    {
        AddMappingsFromAssembly(typeof(FooMapping).Assembly);
        AddMappingsFromAssembly(typeof(BarMapping).Assembly);
        // Where FooMapping and BarMapping is in the same Assembly. 
    }
}

显然这对于 ClassMap 映射来说不是问题。但对于 SubclassMap 它也不能处理它，从而导致重复映射 - 从而导致 DuplicateMappingException。删除 PersistenceModel 中的重复项可以解决该问题。

Discovered the problem. It turned out that I did reference the same Assembly several times in the PersistenceModel used to configure the database:

public class MappingsPersistenceModel : PersistenceModel
{
    public MappingsPersistenceModel()
    {
        AddMappingsFromAssembly(typeof(FooMapping).Assembly);
        AddMappingsFromAssembly(typeof(BarMapping).Assembly);
        // Where FooMapping and BarMapping is in the same Assembly. 
    }
}

Apparently this is not a problem for ClassMap-mappings. But for SubclassMap it doesn't handle it as well, causing duplicate mappings - and hence the DuplicateMappingException. Removing the duplicates in the PersistenceModel fixes the problem.

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