Question

I have a one-to-many relationship between Foo and Bar and I cannot perform an insert (I’ve only tried select and insert so far…select seems to be working just fine, insert fails every time).

Table Definitions:

CREATE TABLE [Bar](
[Id] [int] IDENTITY(1,1) NOT NULL,
[DateField] [datetime] NULL,
[StringField] [varchar](8000) NULL
CONSTRAINT [PK_Bar] PRIMARY KEY CLUSTERED([Id] ASC)) ON PRIMARY

CREATE TABLE [Foo](
[Id] [int] IDENTITY(1,1) NOT NULL,
[BarId] [int] NOT NULL,
[DateField] [date] NOT NULL,
[StringField] [varchar](100) NOT NULL,
[GorpId] [int] NOT NULL,
[BoolField] [bit] NOT NULL
CONSTRAINT [PK_Foo] PRIMARY KEY CLUSTERED([Id] ASC))

ALTER TABLE [dbo].[Foo]  WITH CHECK ADD  CONSTRAINT [FK_Foo_Bar] FOREIGN KEY([BarId])
REFERENCES [dbo].[Bar] ([Id])
GO

Class Definitions:

public class Foo
{
    public virtual int Id { get; set; }
    public virtual Bar Bar{ get; set; }
    public virtual DateTime DateField{ get; set; }
    public virtual string StringField{ get; set; }
    public virtual Gorp Gorp{ get; set; }
    public virtual bool BoolField{ get; set; }
}

public class Bar
{
    public virtual int Id { get; set; }
    public virtual DateTime DateField{ get; set; }
    public virtual string StringField{ get; set; }

    public virtual ICollection<Foo> Foos{ get; set; }

    public Bar()
    {
        Foos= new List<Foo>();
    }

    public virtual void AddFoo(Foo foo)
    {
        foo.Bar = this;
        Foos.Add(foo);
    }
}

Mappings:

public class FooMap : ClassMap<Foo>
{
    public FooMap()
    {
        Id(x => x.Id).UnsavedValue(0).GeneratedBy.Identity();
        Map(x => x.DateField);
        Map(x => x.BoolField);
        Map(x => x.StringField);
        References(x => x.Gorp)
          .Column("GorpId")
          .Class<Gorp>();
        References(x => x.Bar)
          .Column("BarId")
          .Not.Nullable();
    }
}

public class BarMap : ClassMap<Bar>
{
    Id(x => x.Id).UnsavedValue(0).GeneratedBy.Identity();
    Map(x => x.DateField);
    Map(x => x.StringField);

    HasMany<Foo>(x => x.Foos)
      .AsBag()
      .Cascade.SaveUpdate()
      .ForeignKeyConstraintName("FK_Foo_Bar")
      .Inverse()
      .KeyColumn("BarId")
      .Not.KeyNullable();
}

Generated XML:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="property" auto-import="true" default-cascade="none" default-lazy="true">
    <class xmlns="urn:nhibernate-mapping-2.2" mutable="true" name="MyApp.Domain.Model.Bar, MyApp.Domain, Version=3.5.0.0, Culture=neutral, PublicKeyToken=null" table="`Bar`">
        <id name="Id" type="System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" unsaved-value="0">
            <column name="Id" />
            <generator class="identity" />
        </id>
        <property name="DateField" type="System.DateTime, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <column name="DateField" />
        </property>
        <property name="StringField" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <column name="StringField" />
        </property>
        <bag cascade="save-update" inverse="true" name="Foos" mutable="true">
            <key foreign-key="FK_Foo_Bar" not-null="true">
                <column name="BarId" />
            </key>
            <one-to-many class="MyApp.Domain.Model.Foo, MyApp.Domain, Version=3.5.0.0, Culture=neutral, PublicKeyToken=null" />
        </bag>
    </class>
</hibernate-mapping>

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="property" auto-import="true" default-cascade="none" default-lazy="true">
    <class xmlns="urn:nhibernate-mapping-2.2" mutable="true" name="MyApp.Domain.Model.Foo, MyApp.Domain, Version=3.5.0.0, Culture=neutral, PublicKeyToken=null" table="`Foo`">
        <id name="Id" type="System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" unsaved-value="0">
            <column name="Id" />
            <generator class="identity" />
        </id>
        <property name="DateField" type="System.DateTime, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <column name="DateField" />
        </property>
        <property name="BoolField" type="System.Boolean, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <column name="BoolField" />
        </property>
        <property name="StringField" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
             <column name="StringField" />
        </property>
        <many-to-one class="MyApp.Domain.Model.Gorp, MyApp.Domain, Version=3.5.0.0, Culture=neutral, PublicKeyToken=null" name="Gorp">
            <column name="GorpId" />
        </many-to-one>
        <many-to-one class="MyApp.Domain.Model.Bar, MyApp.Domain, Version=3.5.0.0, Culture=neutral, PublicKeyToken=null" insert="false" name="Bar" update="false">
            <column name="BarId" not-null="true" />
        </many-to-one>
    </class>
</hibernate-mapping>

Exception:

could not insert: [MyApp.Domain.Model.Foo][SQL: INSERT INTO [Foo] (DateField, BoolField, StringField, GorpId, BarId) VALUES (?, ?, ?, ?, ?); select SCOPE_IDENTITY()]

What am I missing/misunderstanding?

Answer 1

Thank you, Dave, for pointing me in the right direction. One of the Date fields was nullable in the database, the other was not. I changed my class and my map to reflect that. Voila! It worked!

Too bad the original error message didn’t tell me there was an issue with a datetime field, it would’ve saved me some headaches.

I made the following changes:

public class Foo
{
    public virtual int Id { get; set; }
    public virtual Bar Bar{ get; set; }
    public virtual DateTime DateField{ get; set; }
    public virtual string StringField{ get; set; }
    public virtual Gorp Gorp{ get; set; }
    public virtual bool BoolField{ get; set; }

    public Foo()
    {
        DateField = new DateTime(1753, 1, 1);
    }
}

public class Bar
{
    public virtual int Id { get; set; }
    public virtual DateTime? DateField{ get; set; }
    public virtual string StringField{ get; set; }

    public virtual ICollection<Foo> Foos{ get; set; }

    public Bar()
    {
        DateField = new DateTime(1753, 1, 1);
        Foos= new List<Foo>();
    }

    public virtual void AddFoo(Foo foo)
    {
        foo.Bar = this;
        Foos.Add(foo);
    }
}


public class FooMap : ClassMap<Foo>
{
    public FooMap()
    {
        Id(x => x.Id).UnsavedValue(0).GeneratedBy.Identity();
        Map(x => x.DateField);
        Map(x => x.BoolField);
        Map(x => x.StringField);
        References(x => x.Gorp)
          .Column("GorpId")
          .Class<Gorp>();
        References(x => x.Bar)
          .Column("BarId")
          .Not.Nullable();
    }
}

public class BarMap : ClassMap<Bar>
{
    Id(x => x.Id).UnsavedValue(0).GeneratedBy.Identity();
    Map(x => x.DateField)
          .Nullable();
    Map(x => x.StringField);

    HasMany<Foo>(x => x.Foos)
      .AsBag()
      .Cascade.SaveUpdate()
      .Fetch.Join()
      .ForeignKeyConstraintName("FK_Foo_Bar")
      .Inverse()
      .KeyColumn("BarId")
      .Not.KeyNullable()
      .Table("Foo");
}