Develop Reference

NHibernate Tree structure update root problem

I have a tree structure mapped to the data base in a table like this:
UID numeric(18, 0)
NodeUID varchar(50)
Text nvarchar(50)
TreeLevel int
ParentUID varchar(50)
OrderInLevel int
IsLeaf bit
It is an old table and I cannot change it so bear with me...
The NodeUID is a GUID.
the ParentUID column is mapped to the NodeId of a different row.
A root node has a value of "0" in its ParentUID column.
I am trying to map the Tree with NHibernate like this:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="BasicFW.Core.Domain.NavigationTree.UsersNavigationTreeNode, BasicFW.Core" table="bDoxTreeNodes" lazy="false" schema="bDox.dbo">
<id name="NodeUId">
<column name="NodeUID"/>
<generator class="assigned"/>
</id>
<property name="Text">
<column name="Text"/>
</property>
<property name="TreeLevel">
<column name="TreeLevel"/>
</property>
<property name="IsLeaf">
<column name="IsLeaf"/>
</property>
<many-to-one name="Parent" class="BasicFW.Core.Domain.NavigationTree.UsersNavigationTreeNode, BasicFW.Core" column="ParentUID" not-found="ignore"/>
<bag name="Children" lazy="false" order-by="OrderInLevel ASC" cascade="all-delete-orphan" inverse="true">
<key column="ParentUID"/>
<one-to-many class="BasicFW.Core.Domain.NavigationTree.UsersNavigationTreeNode, BasicFW.Core" />
</bag>
</class>
</hibernate-mapping>
The thing is that when I try to update a node ( and a root node in specifies ) the Parent property is null and so NHibernate try`s to Update the ParentUID column to null, and so it failles since to column will not accept null.
thanks

Can you create a trigger for that table? If yes, you could perhaps create a trigger that fires before update/insert. Something like:
create trigger TreeNode_before before insert, update
on TreeNode
referencing NEW as _new
for each row
begin
if _new.ParentUID is null then
set _new.ParentUID = '0';
end if;
end;
Edit: An alternative would be using an interceptor. I have not used that myself but according to the following question it should work in your case, too.
Edit: fixed the link.
NHibernate write value = NULL when ID < 0

I have found the correct mapping that worked, here is the mapping for my tree.
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="BasicFW.Core.Domain.NavigationTree.UsersNavigationTreeNode, BasicFW.Core" table="TreeNodes" lazy="false" >
<id name="NodeID">
<column name="NodeUID"/>
<generator class="assigned"/>
</id>
<property name="Text">
<column name="Text"/>
</property>
<property name="TreeLevel">
<column name="TreeLevel"/>
</property>
<property name="ParentID" >
<column name="ParentUID" />
</property>
<property name="IsLeaf">
<column name="IsLeaf"/>
</property>
<many-to-one name="Parent" class="BasicFW.Core.Domain.NavigationTree.UsersNavigationTreeNode, BasicFW.Core" column="ParentUID" not-found="ignore" update="false" insert="false"/>
<bag name="Children" lazy="false" order-by="OrderInLevel ASC" inverse="true" cascade="all-delete-orphan">
<key column="ParentUID"/>
<one-to-many class="BasicFW.Core.Domain.NavigationTree.UsersNavigationTreeNode, BasicFW.Core"/>
</bag>
</class>
</hibernate-mapping>
I have disabled the update and insert in the Parent property.

How to map Image type in NHibernate?

I have at my SQL Server 2000 Database a column with type Image. How can I map it into NHibernate?

We used BinaryBlob on the mapping config file, and byte[] on the property.

Below is the sample code that i have used to map an image field. Where BlogImage was a column of Image Datatype mapped to byte type property BlogImage. length="2147483647" was used to ensure copy of full image in to database as nhibernate some times limit the max size of data that is going to be inserted.
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" auto-import="true">
<class name="EAS.MINDSPACE.Infrastructure.Business.Entities.BlogMaster,EAS.MINDSPACE.Infrastructure.Business.Entities" lazy="false" table="BlogMaster" schema="dbo" >
<id name="BlogId" column="BlogId">
<generator class="native" />
</id>
<property name="BlogData" column="BlogData" />
<property name="BlogImage" column="BlogImage" length="2147483647" />
<property name="UserId" column="UserId" />
<property name="CreatedByName" column="CreatedBy" />
<property name="CreatedOn" column="CreatedOn" />
<property name="ReplyCount" column="ReplyCount" />
</class>
</hibernate-mapping>

NHibernate 3.x does all the magic it self.
Sql:
Create table tblCompany (..., Logo image);
NHibernate-Mapping (important to set length!!!):
<class name="Company"
table="tblCompany">
...
<property name="_logo"
column="Logo"
not-null="false"
length="2147483647"
access="field" />
...
</class>
C#-Class:
public class Company {
...
private Image _logo;
...
}

NHibernate mapping of lookup collection (if that makes any sense)

I'm not sure how to ask the question, for I don't know what I don't know, and therefore I don't know the proper terminology for what I'm trying to get the answer to. I will explain my scenario, in hopes that it will help:
I've got three tables, a Book table, a Tag table and a BookTag lookup table.
Each book has an ID, a Title (for starters)
Each tag has an ID, and a Title
Each BookTag has an ID, a BookID, and a TagID.
A book can be tagged with multiple tags, and a tag can be used on more than one BookID.
I've got my objects setup in this fashion:
Book.cs
int BookID
string Title
List<BookTag> Tags
Tag.cs
int TagID
string Title
BookTag.cs
int ID
int BookID
int TagID
I would like the Books.cs class to have a collection of Tags, and not BookTags, but I cannot seem to get the mapping right in NHibernate. This is what I've got for the Book.hbm.xml file:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="DomainModel" namespace="DomainModel.Books">
<class name="DomainModel.Books.Book" table="Books">
<id name="BookID" type="Int32" unsaved-value="0">
<generator class="native"/>
</id>
<property name="Title" type="String" not-null="true"/>
<set lazy="true" name="Tags" table="BookTags" generic="true" inverse="true" cascade="delete">
<key column="BookID"/>
<one-to-many class="DomainModel.Books.BookTag, DomainModel"/>
</set>
</class>
</hibernate-mapping>
And this is my BookTag.hbm.xml:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="DomainModel" namespace="DomainModel.Books">
<class name="DomainModel.Books.BookTag" table="BookTags">
<id column="BookTagID" name="BookTagID" type="Int32" unsaved-value="0">
<generator class="native"/>
</id>
<many-to-one name="Tag">
<column not-null="true" name="TagID"/>
</many-to-one>
<many-to-one name="Book">
<column not-null="true" name="BookID"/>
</many-to-one>
</class>
</hibernate-mapping>
Under this model, I can get to the tag I want by using my object model: Book.Tags[0].Tag, but that just seems inefficient. Can I use NHibernate to map out the BookTags.TagID with the Tags.TagID in the database so that I can get Book.Tags[0] to return a Tag object, instead of a BookTags object? I didn't know of a better way to associate Books to tags so that a tag used on Book1 can be used on Book2 without adding a new entry to the Tags table.
I hope this makes at least some sense. Let me know if you need further clarification. I'll post my solution here if I figure it out before someone answers.

You don't need a BookTag class at all. You can map Book.Tags collection as many-to-many. To do this you will specify BookTag in the map to connect the association. Look here in section 6.8 Bidirectional Associations.

Thank you Tim, that was what I needed. For those that are curious, I "un-mapped" the BookTag table/objects, and now just have a Book object and a Tag object that are used and mapped to NHibernate.
My Book.hbm.xml was updated to this:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="DomainModel" namespace="DomainModel.Books">
<class name="DomainModel.Books.Book" table="Books">
<id name="BookID" type="Int32" unsaved-value="0">
<generator class="native"/>
</id>
<property name="Title" type="String" not-null="true"/>
<bag name="Tags" table="BookTag" generic="true">
<key column="BookID" on-delete="noaction"></key>
<many-to-many class="Tag" column="TagID"></many-to-many>
</bag>
</class>
</hibernate-mapping>

How to use a child object field as part of the compound key in another child in NHibernate

I need to create a new Many-To-One relationship on my User entity which joins against another entity. The problem is the other entity has a compound key of which 1 field is a field in the User entity and the other is a field in another Many-To-One entity.
User.Key -> User.NewThing.Key
User.SubThing.Key -> User.NewThing.Key
Below is the invalid mapping file I am ideally wanting to use where JeanieUserTyped is my newthing and the ApplicationId is the key in question which comes from ShortCode.ApplicationId.
Question is how do I tell it to map the application part of the compound key?
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="JeanieMaster.Domain.Entities" assembly="JeanieMaster.Domain">
<class name="JeanieUser" table="DBSVR1.Jeanie_Master.dbo.JeanieUser" select-before-update="false" optimistic-lock="none">
<id name="Id" column="UserId" type="Int32">
<generator class="identity"/>
</id>
<property name="Mobile" type="String"/>
<property name="UniqueReoccurBillingRefId" type="String"/>
<property name="DateJoined" type="DateTime"/>
<property name="IsActive" type="Boolean"/>
<many-to-one name="MobileNetwork" class="MobileNetwork" column="MobileNetworkId" />
<many-to-one name="ShortCode" class="ShortCode" column="ShortCodeId" />
<many-to-one name="MobileHandset" class="MobileHandset" column="HandsetId" />
<many-to-one name="JeanieUserTyped" class="JeanieUserTyped">
<column name="Mobile" />
<column name="ApplicationId" />
</many-to-one>
</class>
</hibernate-mapping>

Can you give more details, sounds like you have 3 entities,
User
SubThing
NewThing
Where NewThing resolves a Many-to-Many with User and SubThing - am I close?
Maybe like this:
User -< SubThing
| |
/\ /\
NewThing
I don't suppose the composite key stuff in nhibernate is relevant?

NHibernate automatically rename the column name in C#

I couldn't figure out why NHibernate is doing this.
Here's part of my table in MS SQL
CREATE TABLE Person (
nameFamily text,
nameGiven text
)
Here's Person.hbm.xml
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Infosci.Dpd.Model.Person,Infosci.Dpd.Model" table="Person" lazy="true">
<property type="string" name="NameGiven" column="nameGiven" />
<property type="string" name="NameFamily" column="nameFamily" />
</class>
</hibernate>
And in my Person.cs I name my property like the following
string NameFamily
{
get ;
set ;
}
string NameGiven
{
get ;
set ;
}
Then I try to create a record using the following code
ISession session = NHibernateHelper.GetCurrentSession();
Person person = new Person();
person.NameFamily = "lee";
session.Save(person);
And what's weird is when I try do execute it, NHibernate actually change the column name by doing the following
NHibernate: INSERT INTO Person (name_family,name_given.......
So here NHibernate chagne my column name from NameFamily to name_family although I did specify the column name.
Is this a NHibernate bug? Or is there any configuration I need to do?
And here's my hibernate config file
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
<session-factory>
<property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
<property name="dialect">NHibernate.Dialect.MsSql2000Dialect</property>
<property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property>
<property name="connection.connection_string">Data Source=xxxxxxx;Initial Catalog=xx;Integrated Security=True;Pooling=False;User ID=xxxx;Password=xxxx</property>
<property name="show_sql">true</property>
</session-factory>
</hibernate-configuration>
And this is how I create the sessionFactory
sessionFactory = new `Configuration().Configure("hibernate.cfg.xml").
SetNamingStrategy(ImprovedNamingStrategy.Instance).
AddFile("Person.hbm.xml").
BuildSessionFactory();`

That's a "feature" of SetNamingStrategy(ImprovedNamingStrategy.Instance)
It will add underscores before each uppercase letter in mixed-cased names.
Not sure how you disable it (me not being a nhibernate user)

What I end up doing is just use the default naming strategy or SetNamingStrategy(DefaultNamingStrategy.Instance)
the default naming strategy will leave mix-cased name untouched