Hi all,

when i declare a descriminator of type integer I the error mentioned at the end of this post. When I change the type to string, the error disapears.

I suppose however it is better to give the correct type instead of always using a string ?

Anny sugestions ?



I've just updated to 1.2 GA


Thx !

Here is the mapping :

<class name ="PartType" table ="tblTemplateSheetItem">
<id column="TemplateSheetItemID" type="integer" access="nosetter.lowercase-underscore" name ="Id">
<generator class="native"/>
</id>
<discriminator column ="TemplatePartTypeID" type ="integer"></discriminator>
</class>

ERROR :
failed: Could not format discriminator value 'Bics.Common.DomainModel.TemplateManagement.PartTypeOriented' to sql string using the IType NHibernate.Type.Int32Type
NHibernate.MappingException: Could not format discriminator value 'Bics.Common.DomainModel.TemplateManagement.PartTypeOriented' to sql string using the IType NHibernate.Type.Int32Type ---> System.FormatException: Input string was not in a correct format.
at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
at System.Int32.Parse(String s)
c:\net\nhibernate\nhibernate\src\NHibernate\Type\Int32Type.cs(89,0): at NHibernate.Type.Int32Type.FromStringValue(String xml)
c:\net\nhibernate\nhibernate\src\NHibernate\Type\NullableType.cs(133,0): at NHibernate.Type.NullableType.FromString(String xml)
c:\net\nhibernate\nhibernate\src\NHibernate\Type\Int32Type.cs(84,0): at NHibernate.Type.Int32Type.StringToObject(String xml)
c:\net\nhibernate\nhibernate\src\NHibernate\Persister\Entity\SingleTableEntityPersister.cs(358,0): at NHibernate.Persister.Entity.SingleTableEntityPersister..ctor(PersistentClass model, ICacheConcurrencyStrategy cache, ISessionFactoryImplementor factory, IMapping mapping)

The problem is that NH is trying to stuff the class name into an integer column. Try setting the discriminator-value of the class (and subclasses) to an integer value.

Hi all,
I Just found out the real problem, however, I don't have a solution jet.

The problem is that I'm using a class hierarchy containing some classes that are abstract. They do not have a discriminator value.

Here is my class hierarchy :

+ PartType
- DestinationElementDescription
- PrefixElementDescription
++ PartTypeOriented
-- KeyElementDescription
-- ValidFromElementDescription
-- CostElementDescription
+++ PartTypeOrientedWithCode
---QualityElementDescription
---CalendarElementDescription
---TDEElementDescription
---TrafficTypeElementDescription
---ProductElementDescription

The once wit the +sings are subclasses which should not have a discrininator value. The one with the - do have a discriminator value.

Any Idea how to solve this ?


HERE THE COMPLETE MAPPING FILE :


<class name ="PartType" table ="tblTemplateSheetItem">
<id column="TemplateSheetItemID" type="integer" access="nosetter.lowercase-underscore" name ="Id">
<generator class="native"/>
</id>
<discriminator column ="TemplatePartTypeID" type ="string"></discriminator>
<!--property name ="PartTypeID" type="integer" column ="PartTypeID" access="field.lowercase-underscore" /-->
<many-to-one class ="Range" name ="Sheet" column ="TemplateSheetID" not-null ="true" ></many-to-one>
<bag name ="Columns" access ="nosetter.lowercase-underscore" cascade ="all-delete-orphan" inverse ="true">
<key column ="TemplateSheetItemID"></key>
<one-to-many class="Column"/>
</bag>
<subclass name ="DestinationElementDescription" discriminator-value="1"/>
<subclass name ="PrefixElementDescription" discriminator-value="2"/>

<subclass name="PartTypeOriented">
<!-- MAPS TO AN ENUMERATION-->
<property name ="Orientation" type ="Int16" column ="PartTypeOrientation" access ="field.lowercase-underscore"/>
<subclass name ="KeyElementDescription" discriminator-value="3"/>
<subclass name ="ValidFromElementDescription" discriminator-value="8"/>
<subclass name ="CostElementDescription" discriminator-value="11"/>

<subclass name ="PartTypeOrientedWithCode">
<subclass name ="QualityElementDescription" discriminator-value="5"/>
<subclass name ="CalendarElementDescription" discriminator-value="6"/>
<subclass name ="TDEElementDescription" discriminator-value ="7"/>

<subclass name ="TrafficTypeElementDescription" discriminator-value="9"/>
<subclass name ="ProductElementDescription" discriminator-value="10"/>

</subclass>

</subclass>
</class>

What is the value of that column when you use it as a string? Empty?

You might need to define TemplatePartTypeID as a nullable int.

Also, I don't think this is related at all.. but I always thought, probably incorrectly so, that Type had to be the CLS type... and so you'd want to define that as Int32 or System.Int32 and not 'integer'

I've tried a different aproach.
Instead of not providing a discriminator I provide one which will never occure (I put in negative values).
However the problem isn't solved yet. I recieve following exception :

failed: NHibernate.MappingException: Could not format discriminator value 'Bics.Common.DomainModel.TemplateManagement.PartType' to sql string using the IType NHibernate.Type.Int32Type
NHibernate.MappingException: Could not format discriminator value 'Bics.Common.DomainModel.TemplateManagement.PartType' to sql string using the IType NHibernate.Type.Int32Type ---> System.FormatException: Input string was not in a correct format.


I do not understand this exception because there is no discriminator applied on the class PartType, it is the base class.

MODIFIED MAPPING FILE

<class name ="PartType" table ="tblTemplateSheetItem">
<id column="TemplateSheetItemID" type="integer" access="nosetter.lowercase-underscore" name ="Id">
<generator class="native"/>
</id>
<discriminator column ="TemplatePartTypeID" type ="integer" ></discriminator>
<!--property name ="PartTypeID" type="integer" column ="PartTypeID" access="field.lowercase-underscore" /-->
<many-to-one class ="Range" name ="Sheet" column ="TemplateSheetID" not-null ="true" ></many-to-one>
<bag name ="Columns" access ="nosetter.lowercase-underscore" cascade ="all-delete-orphan" inverse ="true">
<key column ="TemplateSheetItemID"></key>
<one-to-many class="Column"/>
</bag>
<subclass name ="DestinationElementDescription" discriminator-value="1"/>
<subclass name ="PrefixElementDescription" discriminator-value="2"/>

<subclass name="PartTypeOriented" discriminator-value ="-1" >
<!-- MAPS TO AN ENUMERATION-->
<property name ="Orientation" type ="Int16" column ="PartTypeOrientation" access ="field.lowercase-underscore"/>

<subclass name ="KeyElementDescription" discriminator-value="3"/>
<subclass name ="ValidFromElementDescription" discriminator-value="8"/>
<subclass name ="CostElementDescription" discriminator-value="11"/>

<subclass name ="PartTypeOrientedWithCode" discriminator-value ="-2">
<subclass name ="QualityElementDescription" discriminator-value="5"/>
<subclass name ="CalendarElementDescription" discriminator-value="6"/>
<subclass name ="TDEElementDescription" discriminator-value ="7"/>

<subclass name ="TrafficTypeElementDescription" discriminator-value="9"/>
<subclass name ="ProductElementDescription" discriminator-value="10"/>

</subclass>

</subclass>
</class>

FOUND THE ERROR !

I did not realize that a discriminator value shoud be specified on the class defining the discrininator.
Because I was using strings as a discriminator in the past I never noticed this because by default the class name is used as discriminator...

Could you post the new mapping? I have similar issue of setting Integer discriminator-value.
Thanks.

Sure,
apparently the trick is to put in a value which will not be present in the DB, so nHibernate will not construct this type directly

Probably something commonly know by hibernate veterans, but for me this is all new and I could not find a result to this immediately.


Here you go, my new mapping file :

<class name ="PartType" table ="tblTemplateSheetItem" discriminator-value="-1">
<id column="TemplateSheetItemID" type="integer" access="nosetter.lowercase-underscore" name ="Id">
<generator class="native"/>
</id>
<discriminator column ="TemplatePartTypeID" type ="integer" ></discriminator>
<!--property name ="PartTypeID" type="integer" column ="PartTypeID" access="field.lowercase-underscore" /-->
<many-to-one class ="Range" name ="Sheet" column ="TemplateSheetID" not-null ="true" ></many-to-one>
<bag name ="Columns" access ="nosetter.lowercase-underscore" cascade ="all-delete-orphan" inverse ="true">
<key column ="TemplateSheetItemID"></key>
<one-to-many class="Column"/>
</bag>
<subclass name ="DestinationElementDescription" discriminator-value="1"/>
<subclass name ="PrefixElementDescription" discriminator-value="2"/>

<subclass name="PartTypeOriented" discriminator-value ="-2" >
<!-- MAPS TO AN ENUMERATION-->
<property name ="Orientation" type ="Int16" column ="PartTypeOrientation" access ="field.lowercase-underscore"/>

<subclass name ="KeyElementDescription" discriminator-value="3"/>
<subclass name ="ValidFromElementDescription" discriminator-value="8"/>
<subclass name ="CostElementDescription" discriminator-value="11"/>

<subclass name ="PartTypeOrientedWithCode" discriminator-value ="-3">
<subclass name ="QualityElementDescription" discriminator-value="5"/>
<subclass name ="CalendarElementDescription" discriminator-value="6"/>
<subclass name ="TDEElementDescription" discriminator-value ="7"/>

<subclass name ="TrafficTypeElementDescription" discriminator-value="9"/>
<subclass name ="ProductElementDescription" discriminator-value="10"/>

</subclass>

</subclass>
</class>

Probably something commonly know by hibernate veterans, but for me this is all new and I could not find a result to this immediately.

Been using NHibernate for years now, and this is the first time I've used discriminator columns, and I ran into this problem. Thanks for describing the solution.

This is NHibernate's bad design IMO. Abstract classes shouldn't need a discrim value, and even if they do, there is no way NHibernate should just default it to the class name if sub or superclasses provide explicit values; this is typically a sign of programmer error.

Hi,
I'm glad my post is useful for somebody.

If you know the behaviour it does not bother me. The problem is that this behaviour is not mentioned CLEARLY in the documentation.

I bought the book "hibernate in action" and I could never find a description of this kind of situations although it does not seem that exotic.

If nHibernate wants to be successful in the future, it needs clear documentation. I think a lot of newcomers from the .net front are jumping in. To catch them, clear doc's are key to success.

True. You should submit an addendum to the 'discriminator' section to JIRA.

Could you tell me how I could do it ? Then I can add it.

Sure! Check out http://jira.nhibernate.org/. I think your forums login will work there. You can create a new issue. Try to reference every point in the documentation where the given addendum/erratum is needed.

I was having the same problem, also being a newbie. Thanks for posting your solution.

Great if it has been usefull for somebody !