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">
<开发者_高级运维;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.
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