There are two entities in my code which are participated in a many-to-one relationship. The problem is when i try to delete the parent it says :
ORA-02292: integrity constraint violated - child record found
As you can see below there is a User Security Parameter entity in my project which can have related children called Exceptional User Security parameters.
I expect the ORM to delete the found child records when it wants to eliminate their parent
<bag name="ExeptionalUserSecurityParameters" inverse="true" lazy="false" access="property" cascade="none" batch-size="256">
<key>
<column name="Key" />
</key>
<one-to-many class="ExeptionalUserSecurityParameter"/>
</bag>
<many-to-one name="UserSecurityParameter" cascade="all-delete-orphan" fetch="join"
class="UserSecurityParameters" >
<column name="Key" />
</many-to-one>
How can I avoid this issue?
Almost always (well, always) I do use cascading like this:
//<bag name="ExeptionalUserSecurityParameters" cascade="none" ...
<bag name="ExeptionalUserSecurityParameters" cascade="all-delete-orphan" ...
//<many-to-one name="UserSecurityParameter" cascade="all-delete-orphan"
<many-to-one name="UserSecurityParameter" cascade="none"
that should solve the issue. If the collection owner is deleted.. who ever reference it - is deleted as well. But not vice versa
I'm trying to use an NHibernate filter to filter on a parent class's property, but I keep getting an error that the multi-part identifier "Parent.Active" could not be bound. My filter-def is:
<filter-def name="useActive" />
My parent class has this in the mapping:
<property name="Active">
<column name="ACTIVE" not-null="true" />
</property>
<bag name="Children" table="CHILDREN" inverse="true">
<key>
<column name="PARENT_ID_IN_CHILD" />
</key>
<one-to-many class="ChildType" />
</bag>
My child class has this in the mapping:
<many-to-one name="Parent" class="ParentTyle">
<column name="PARENT_ID_IN_CHILD" />
</many-to-one>
<filter name="useActive" condition="Parent.Active = 1" />
How can I get NHibernate to check the parent column when filtering?
edit: I'm enabling the filter using mySession.EnableFilter("useActive");. I'm also using LINQ-to-NHibernate, but I don't think that should matter.
The error you're receiving came from SQL Server that can't find the column "Active" on the table "Parent".
Keep in mind that when you're defining a filter the string that you put in the condition will simply be appended in the where condition of the select as is. If you want to filter for that field you must first identify the alias nHibernate use for your SQL query than put that alias instead of "Parent". it coube something like "mytable_0" or something like that.
I've got a scheme (fields aren't necessary):
a busy cat http://picsearch.ru/share/image-BCE8_4E168F3B.jpg
I've got mappings:
Entity
<class name="LogicalModel.Entity" table="`Entity`" lazy="true">
<id name="Id" ..> ... </id>
<bag name="Attributes" lazy="true" cascade="all-delete-orphan" fetch="select" batch-size="1" access="property" inverse="true">
<key column="`Entity`" />
<one-to-many class="LogicalModel.Attribute" />
</bag>
<bag name="Keys" lazy="true" cascade="all-delete-orphan" fetch="select" batch-size="1" access="property" inverse="true">
<key column="`Entity`" />
<one-to-many class="LogicalModel.Key" />
</bag>
</class>
Attribute
<class name="LogicalModel.Attribute" table="`Attribute`" lazy="true">
<id name="Id" ..> ... </id>
<many-to-one name="Type" class="LogicalModel.Entity" column="`Type`" cascade="save-update" fetch="select" not-null="true" foreign-key="fk_TypeAttribute" />
<many-to-one name="Entity" class="LogicalModel.Entity" column="`Entity`" cascade="none" fetch="select" not-null="true" foreign-key="fk_EntityAttributes" />
</class>
Key
<class name="LogicalModel.Key" table="`Key`" lazy="true">
<id name="Id" ..> ... </id>
<bag name="KeyAttributes" lazy="true" cascade="all-delete-orphan" fetch="select" access="property" inverse="true">
<key column="`Key`" />
<one-to-many class="LogicalModel.KeyAttribute" />
</bag>
<many-to-one name="Entity" class="LogicalModel.Entity" column="`Entity`" cascade="none" fetch="select" not-null="true" foreign-key="fk_EntityKeys" />
</class>
KeyAttribute:
<class name="LogicalModel.KeyAttribute" table="`KeyAttribute`" lazy="false">
<id name="Id" ..> ... </id>
<many-to-one name="Attribute" class="LogicalModel.Attribute" column="`Attribute`" cascade="save-update" fetch="select" not-null="true" foreign-key="fk_AttributeKeyAttribute" />
<many-to-one name="Key" class="LogicalModel.Key" column="`Key`" cascade="none" fetch="select" not-null="true" foreign-key="fk_KeyKeyAttributes" />
</class>
Now please take a look...
As you see, We've got one-way master association KeyAttribute - Attribute, so it's just many-to-one and I don't need back association at all.
Now the problem is when I'm trying to delete whole graph - delete Entity object (notice: Entity actually aren't loaded at all, it's just set of proxies, that's why NHibernate make additional SELECT queries to check references before delete)
like this
Session.Delete(Entity); // here PropertyValueException:
// not-null property references a null or transient value: LogicalModel.KeyAttribute.Attribute
Session.Flush(); // Actually I use transactions in my code, but don't mind
SQL Profiler:
exec sp_executesql N'SELECT entities0_.[Id] as Id1_1_, entities0_.[Id] as Id1_45_0_,
FROM [Entity] entities0_ WHERE entities0_.[LogicalModel]=#p0',N'#p0 uniqueidentifier',#p0='DC8F8460-9C41-438A-8334-97D0A94E2528'
exec sp_executesql N'SELECT attributes0_.[Entity] as Entity12_1_, attributes0_.[Id] as Id1_1_, attributes0_.[Id] as Id1_16_0_, attributes0_.[Type] as Type11_16_0_, attributes0_.[Entity] as Entity12_16_0_
FROM [Attribute] attributes0_ WHERE attributes0_.[Entity]=#p0',N'#p0 uniqueidentifier',#p0='63E4D568-EAB2-4DF2-8FED-014C8CB2DE22'
exec sp_executesql N'SELECT keys0_.[Entity] as Entity4_1_, keys0_.[Id] as Id1_1_, keys0_.[Id] as Id1_43_0_, keys0_.[Entity] as Entity4_43_0_
FROM [Key] keys0_ WHERE keys0_.[Entity]=#p0',N'#p0 uniqueidentifier',#p0='63E4D568-EAB2-4DF2-8FED-014C8CB2DE22'
exec sp_executesql N'SELECT keyattribu0_.[Key] as Key4_1_, keyattribu0_.[Id] as Id1_1_, keyattribu0_.[Id] as Id1_0_0_, keyattribu0_.[Attribute] as Attribute3_0_0_, keyattribu0_.[Key] as Key4_0_0_
FROM [KeyAttribute] keyattribu0_ WHERE keyattribu0_.[Key]=#p0',N'#p0 uniqueidentifier',#p0='103D8FB3-0B17-4F51-8AEF-9623616AE282'
So what we can see:
not-null property references a null or transient value: LogicalModel.KeyAttribute.Attribute
happened just after NH check field Attribute (not-null constraint in db, it's ok) in class KeyAttribute (see profiler log).
It's pretty fun, cause NH have to delete Attributes and KeyAttributes both, NH read information about Attribute field in KeyAttribute class, FOUND it in DB, NOT FOUND it in NH session (!!!) (cause Attributes was loaded before), and just throw this stupid error.
What I've already tried to do:
1. make not-null="false". In this case NH makes additional update - try to set Attribute=NULL - cause constraint violation in DB.
2. set lazy="false", lazy="no-proxy" on many-to-one association for KeyAttribute-Attribute - nothing;
Now I don't like the idea of interceptors because there are to many scenarios where I've got the same situation, I need common solution
Please, guys, any suggestions?
In my opinion it may be caused by your lazy load on all entities of model.
When deleting entity, it loads and delete referenced Attribute list, loads referenced Key list, loads referenced KeyAttribute list (to have key of deletion) and then it falls in not-null property references a null or transient value because referenced Attribute has been deleted before in session.
You can check that by removing all lazy load in your mapping files.
A quick solution may be to keep lazy load but to force a full load of model (with hibernate initialize()) when deleting, for example in a Delete(Entity) static method in Entity factory.
Have you tried setting on-delete="cascade" in
<class name="LogicalModel.Key" table="`Key`" lazy="true">
<id name="Id" ..> ... </id>
<bag name="KeyAttributes" lazy="true" cascade="all-delete-orphan" fetch="select" access="property" inverse="true">
<key column="`Key`" on-delete="cascade" />
<one-to-many class="LogicalModel.KeyAttribute" />
</bag>
<many-to-one name="Entity" class="LogicalModel.Entity" column="`Entity`" cascade="none" fetch="select" not-null="true" foreign-key="fk_EntityKeys" />
Because in profile you will see nh trying to update something to null which is non nullable
NH sometimes requires to set references to null. Usually this is to avoid problems in models where circular references exist. But it is not always clever enough to find a way to avoid it, even if the is one.
So it may require to allow nulls in some foreign key fields, of course not only in the mapping file, also in the database. It actually should solve the problem.
Alternatively, you could also delete the data table by table using HQL. This works fine in all cases where you don't have inheritance and if you know all entities and the order to delete them:
object entityId;
// gets keys to delete
List<object> keyIds = Session
.CreateQuery("select id from Key where Entity = :entity")
.SetEntity("entity", Entity)
.List<object>();
// delete KeyAttribute which reference the key
Session.CreateQuery("delete KeyAttribute where Key.id in (:keyIds)")
.SetParameterList("keyIds", keyIds)
.ExecuteUpdate();
// delete the keys
Session.CreateQuery("delete Key where id in (:keyIds)")
.SetParameterList("keyIds", keyIds)
.ExecuteUpdate();
// get attributes to delete
List<object> attributeIds = Session
.CreateQuery("select id from Attribute where Entity = :entity")
.SetEntity("entity", Entity)
.List<object>();
// delete KeyAttributes which reference the attributes
Session.CreateQuery("delete KeyAttribute where Attribute.id in (:attributeIds)")
.SetParameterList("attributeIds", attributeIds )
.ExecuteUpdate();
// delete the attributes
Session.CreateQuery("delete Attribute where id in (:attributeIds)")
.SetParameterList("attributeIds", attributeIds )
.ExecuteUpdate();
Session.CreateQuery("delete Entity where id = :entityId")
.SetParameter("entityId", Entity.Id)
.ExecuteUpdate();
Note:
You may break the parameter lists into piece if they exceed the size of around 2000 (in SQL Server).
The session gets out of synch when deleting directly in the database. This doesn't cause any problems when deleting is all you do. When you are doing other staff in the same session, clear the session after deleting.
It is possible to specify an arbitrary SQL where clause for collection mappings. For example:
<map name="myEntity" where="foo = 1" />
However if the column name is ambiguous for some reason, the sql fails. For example, this can occur if you are trying to use joins for example.
Given that the table aliases are automatically generated, you can't qualify the column name. This makes the feature seem rather silly. Does anyone know if there is a work around?
NHibernate should figure out the correct alias for the property you are referencing. Is foo a mapped property of the item entity type (the item type that is in the map collection) ?
For example this works:
<class name="Category" table="Category">
<id name="Id">
<generator class="guid.comb" />
</id>
<property name="Name" not-null="true" length="255" />
<bag name="ProductList" table="Product" cascade="none" where="Name like '%test%'" fetch="join">
<key column="CategoryId" />
<one-to-many class="Product" />
</bag>
</class>
There is a property on both Category and the Product class named "Name" but nhibernate will in this case use the on defined on the Product class.
I have a base class for content items in a CMS I'm building. It's currently marked abstract because I only want derived classes to be instantiated. Derived classes like BlogPost, Article, Photo, etc. are set up as a joined subclass to my ContentBase class in nHibernate.
I'm trying to set up a many-to-many mapping between this class and a Tag class. I want to have a collection of Tags on the ContentBase class, and a collection of ContentBase items on the tag class.
Will nHibernate allow me to map the abstract ContentBase class as a collection on the Tag class? I'm assuming not since it wouldn't be able to instantiate any instances of this class when reconstituting a Tag entity from the db. I really don't want to have to have to use a collection of content items per type (e.g. TaggedBlogPosts, TaggedArticles, etc.) on the Tag class.
The whole reason I'm doing this is because logically, a content item can have many tags, and 1 tag can belong to multiple content items. in order for nHibernate to manage the relationships for me in a mapping table, I believe I have to set up a many-to-many association and add the Tag to the ContentBase.Tags collection and then the content item to the Tags.TaggedContentItems collection before the mapping table entry is created in nHibernate.
Here are my mappings for reference:
<class name="CMS.Core.Model.Tag,CMS.Core" table="bp_Tags">
<id column="TagName" name="TagName" type="String" unsaved-value="">
<generator class="assigned" />
</id>
<bag name="_taggedContentList" table="bp_Tags_Mappings" inverse="true" cascade="save-update" lazy="true">
<key column="TagName" />
<many-to-many class="CMS.Core.Model.ContentBase,CMS.Core" column="Target_Id" />
</bag>
</class>
<class name="CMS.Core.Model.ContentBase,CMS.Core" table="bp_Content">
<id name="Id" column="Id" type="Int32" unsaved-value="0">
<generator class="native"></generator>
</id>
<property name="SubmittedBy" column="SubmittedBy" type="string" length="256" not-null="true" />
<property name="SubmittedDate" column="SubmittedDate" type="datetime" not-null="true" />
<property name="PublishDate" column="PublishDate" type="datetime" not-null="true" />
<property name="State" column="State" type="CMS.Core.Model.ContentStates,CMS.Core" not-null="true" />
<property name="ContentType" column="ContentType" type="CMS.Core.Model.ContentTypes,CMS.Core" not-null="true" />
<bag name="_tagsList" table="bp_Tags_Mappings" lazy="false" cascade="save-update">
<key column="Target_Id" />
<many-to-many class="CMS.Core.Model.Tag,CMS.Core" column="TagName" lazy="false" />
</bag>
...
<joined-subclass name="CMS.Core.Model.BlogPost,CMS.Core" table="bp_Content_BlogPosts" >
<key column="Id" />
<property name="Body" type="string" column="Body" />
<property name="Title" type="string" column="Title" />
</joined-subclass>
...
I would also assume that Hibernate would need to instantiate the base class, which makes sense, as there is data directly linked to it in the DB.
It looks like your data entities are in a separate assembly from your main application. The point of not instantiating the base is from a business point of view, so if you make the constructor internal to the Core assembly, does that accomplish what you want? If not, it may be helpful to ask yourself: who am I protecting this functionality from?
NHibernate should allow you to map the abstract class as a collection as long as you map the abstract class itself (it looks like you have).
An alternative is to change your strategy to the Table-per-class-hierachy approach. This puts all your content into a single table with a discriminator column to define the type of content. NHibernate knows how to materialize each content type based on the discriminator. The downside is that:
Each unique property of the concrete classes has to be of type nullable.
This table can get unwieldy if there are a lot of properties specific to each concrete class.
The table-per-class-hierachy is the preferred default mapping strategy (per NHibernate in Action). I would start with the approach and modify it to table-per-subclass when the need is certain.
A whole separate solution would be keep the mapping as is and rely on query to get the content by tag without worrying about the tags keeping a reference to a collection of content.