The foreign key generator is not documented and it’s not readily obvious how to
implement it.
<generator class="foreign">
<param name="property">Foo</param>
</generator>
...
<one-to-many name="Foo" />
See
http://weblogs.asp.net/ricardoperes/archive/2009/06/10/nhibernate-mappings.aspx
for an example.
From: Fabio Maulo
Sent: Wednesday, October 27, 2010 3:35 PM
To: [email protected]
Subject: Re: [nhusers] Re: How to map a class and a composite with multiple
sub-types to the same database table?
5.1.4.1. generator
The required <generator> child element names a .NET class used to generate
unique identifiers for instances of the persistent class.
On Wed, Oct 27, 2010 at 1:05 PM, [email protected]
<[email protected]> wrote:
Fabio,
I appreciate your insights. I will be sure to add one of the
NHibernate books to my reading list. When I first began using
NHibernate 1.2 (yes I know this is an older version), I read the docs
end to end.
I looked at the link you provided above,
http://nhforge.org/doc/nh/en/index.html#mapping-declaration-id, and it
made no mention of how to use <generator class="foreign">
In the meantime, I am simply trying to avoid creating an entirely new
table for essentially one field. Due to my admittedly inadequate grasp
of this particular problem, I may to have to do just that.
I will try generating the schema from the mapping file to see if that
provides any help.
Thanks,
Robert
On Oct 26, 5:57 pm, Fabio Maulo <[email protected]> wrote:
> IMO you are using a "try-catch" technique to study how work with
NHibernate.http://nhforge.org/doc/nh/en/index.html#mapping-declaration-id
>
> <http://nhforge.org/doc/nh/en/index.html#mapping-declaration-id>in
additionhttp://nhforge.org/content/Books.aspx
>
> <http://nhforge.org/content/Books.aspx>btw try to create the DB using
> NHibernate and then check the differences.
> Configuration cfg = ....;
> new SchemaExport(cfg).Create(false, true);
>
> On Tue, Oct 26, 2010 at 4:20 PM, mailto:[email protected] <
>
>
>
> [email protected]> wrote:
> > If I remove
>
> > <generator class="foreign">
> > <param name="property">structural</param>
> > </generator>
>
> > it gives an error:
>
> > The element 'id' in namespace 'urn:nhibernate-mapping-2.2' has
> > incomplete content. List of possible elements expected:
> > 'urn:nhibernate-mapping-2.2:meta urn:nhibernate-mapping-2.2:column
> > urn:nhibernate-mapping-2.2:generator'.
>
> > How do I fix this?
>
> > Thanks,
>
> > Robert
>
> > On Oct 26, 1:56 pm, Fabio Maulo <[email protected]> wrote:
> > > It is available btw with
> > > <generator class="foreign">
> > > <param name="property">structural</param>
> > > </generator>
> > > you are saying to NH that he must assign the ID and, probably, you have
> > an
> > > identity in the Structural table.
>
> > > On Tue, Oct 26, 2010 at 3:46 PM, [email protected] <
>
> > > mailto:[email protected]> wrote:
> > > > No, I'm not generating the database with NHibernate. Not completely
> > > > sure that feature was available in version 1.2.
>
> > > > Thanks,
>
> > > > Robert
>
> > > > On Oct 26, 1:32 pm, Fabio Maulo <[email protected]> wrote:
> > > > > <generator class="foreign">
> > > > > <param name="property">structural</param>
> > > > > </generator>
>
> > > > > are you generating the DB using NH ?
>
> > > > > On Tue, Oct 26, 2010 at 3:17 PM, [email protected] <
>
> > > > > [email protected]> wrote:
> > > > > > When trying to map a class and a composite with multiple sub-types
> > to
> > > > > > the same table, I get the error "Cannot insert explicit value for
> > > > > > identity column in table 'Structural' when IDENTITY_INSERT is set
> > to
> > > > > > OFF." when attempting to create an instance of "Structural" that
> > > > > > pertains to the mapping file below. I am using NHibernate 1.2 if
it
> > > > > > matters. I found the following article that suggest this type of
> > > > > > mapping is possible:
>
> >http://colinjack.blogspot.com/2008/03/nhibernate-working-around-lack-.
> > > > ..
>
> > > > > > <?xml version="1.0" encoding="utf-8" ?>
> > > > > > <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
> > > > > > <class name="Esl.Domain.Buildings.Structural, Esl.Domain"
> > > > > > table="Structural">
> > > > > > <id name="id" access="field" column="Id">
> > > > > > <generator class="native" />
> > > > > > </id>
> > > > > > <property name="isDirty" column="IsDirty"
> > > > access="field"/>
> > > > > > <property name="solarHeatGain"
> > column="SolarHeatGain"
> > > > > > access="field" type="Nullables.NHibernate.NullableDoubleType,
> > > > > > Nullables.NHibernate" />
> > > > > > <property name="wallCavityInsulation"
> > > > > > column="WallCavityInsulation"
> > > > > > access="field" type="Nullables.NHibernate.NullableDoubleType,
> > > > > > Nullables.NHibernate" />
> > > > > > <property name="wallContinuousInsulation"
> > > > > > column="WallContinuousInsulation" access="field"
> > > > > > type="Nullables.NHibernate.NullableDoubleType,
> > Nullables.NHibernate" /
>
> > > > > > <property name="wallExteriorFinish"
> > > > > > column="WallExteriorFinish"
> > > > > > access="field" />
> > > > > > <property name="uValue" column="UValue"
> > access="field"
> > > > > > type="Nullables.NHibernate.NullableDoubleType,
> > Nullables.NHibernate" /
>
> > > > > > <property name="numberOfBedrooms"
> > > > column="NumberOfBedrooms"
> > > > > > access="field" type="Nullables.NHibernate.NullableInt32Type,
> > > > > > Nullables.NHibernate" />
> > > > > > <many-to-one name="roof" access="field"
> > cascade="all"
> > > > > > class="Esl.Domain.Buildings.Roof, Esl.Domain" column="RoofId" />
>
> > > > > > <one-to-one name="foundation" access="field"
> > cascade="all-delete-
> > > > > > orphan" />
>
> > > > > > <list access="field" name="floors" table="Floors" cascade="all-
> > > > > > delete-orphan">
> > > > > > <key column="StructuralId" />
> > > > > > <index column="Position" />
> > > > > > <one-to-many
> > class="Esl.Domain.Buildings.Floor,
> > > > > > Esl.Domain"/>
> > > > > > </list>
> > > > > > </class>
>
> > > > > > <class name="Esl.Domain.Buildings.Foundation, Esl.Domain"
> > > > > > table="Structural" discriminator-value="-1">
>
> > > > > > <id name="id" access="field" column="Id">
> > > > > > <!--This lets us get away breaking out Foundation into a
class
> > > > > > mapping without
> > > > > > creating another database table or a database migration-->
> > > > > > <generator class="foreign">
> > > > > > <param name="property">structural</param>
> > > > > > </generator>
> > > > > > </id>
> > > > > > <discriminator column="FoundationType" type="integer" />
>
> > > > > > <property name="isDirty" column="FoundationIsDirty"
> > access="field"/
>
> > > > > > <property name="insulation" column="FloorOrSlabInsulation"
> > > > > > access="field" type="Nullables.NHibernate.NullableDoubleType,
> > > > > > Nullables.NHibernate" />
>
> > > > > > <one-to-one constrained="true" name="structural"
> > access="field"/>
>
> > > > > > <subclass name="Esl.Domain.Buildings.SlabFoundation,
Esl.Domain"
> > > > > > discriminator-value="0"/>
> > > > > > <subclass name="Esl.Domain.Buildings.PilingFoundation,
> > Esl.Domain"
> > > > > > discriminator-value="1"/>
> > > > > > <subclass name="Esl.Domain.Buildings.PierAndBeamFoundation,
> > > > > > Esl.Domain"
> > > > > > discriminator-value="2"/>
> > > > > > <subclass
name="Esl.Domain.Buildings.ConditionedBelowFoundation,
> > > > > > Esl.Domain"
> > > > > > discriminator-value="3"/>
> > > > > > </class>
> > > > > > </hibernate-mapping>
>
> > > > > > Any help would be greatly appreciated.
>
> > > > > > Thanks,
>
> > > > > > Robert
>
> > > > > > --
> > > > > > You received this message because you are subscribed to the Google
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> > > > > > To post to this group, send email to [email protected].
> > > > > > To unsubscribe from this group, send email to
> > > > > >
mailto:nhusers%[email protected]<mailto:nhusers%[email protected]>
> >
<mailto:nhusers%[email protected]<mailto:nhusers%[email protected]>
>
> > > >
<mailto:nhusers%[email protected]<mailto:nhusers%[email protected]>
> >
<mailto:nhusers%[email protected]<mailto:nhusers%[email protected]>
>
> > > > > > .
> > > > > > For more options, visit this group at
> > > > > >http://groups.google.com/group/nhusers?hl=en.
>
> > > > > --
> > > > > Fabio Maulo
>
> > > > --
> > > > You received this message because you are subscribed to the Google
> > Groups
> > > > "nhusers" group.
> > > > To post to this group, send email to [email protected].
> > > > To unsubscribe from this group, send email to
> > > >
mailto:nhusers%[email protected]<mailto:nhusers%[email protected]>
> >
<mailto:nhusers%[email protected]<mailto:nhusers%[email protected]>
>
> > > > .
> > > > For more options, visit this group at
> > > >http://groups.google.com/group/nhusers?hl=en.
>
> > > --
> > > Fabio Maulo
>
> > --
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> > To post to this group, send email to [email protected].
> > To unsubscribe from this group, send email to
> >
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> > .
> > For more options, visit this group at
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>
> --
> Fabio Maulo
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