Hello hope someone can help me on this.
I have a situation where I have:
User entity which stores all my users including admins.
Comments entity which stores all comment against users.
my problem is I'm also storing within the comment entity the user id of the admin who made the comment. So now I have the Comment entity having 2 userId fields and when retrieving a User entity it wouldn't fetch any associating comments.
My mapping code is as below:
Within the User Entity..
<set name="MemberComments" cascade="all-delete-orphan" inverse="true">
<key column="UserCommentId"/>
<one-to-many class="IlluminatiCoreUserComment"/>
</set>
Within the UserComment Entity
<id name="UserCommentId">
<generator class="identity"/>
</id>
<many-to-one name="User" class="IlluminatiCoreMember" column="UserId" not-null="true"/>
<property name="Comment" not-null="true"/>
<property name="CreatedTimeStamp" not-null="true"/>
<property name="ModifiedTimeStamp" not-null="true"/>
<many-to-one name="CommentedByUser" class="IlluminatiCoreMember" column="CommentedByUserId" not-null="true" inverse="false"/>
How can I make MemberComments within the User entity point to just the User many-to-one field?
Thanks for your help in advance
The <key> element in User should have the FK to User, not the id of UserComment.
In other words, the same column as the many-to-one, UserId.
Related
I'm trying to map the following classes:
PessoaFisica and PessoaJuridica inherits Pessoa.
Cliente has an association with Pessoa, it may be PessoaJuridica or PessoaFisica.
When I save a Cliente object with PessoaFisica, for example, thats ok. But when I try to update and I set the property Pessoa from Cliente to PessoaJuridica and try to update, it updates, but it generates a new row in table TB_PESSOA and the old row, in PessoaFisica is not deleted. It creates a new row to PessoaJuridica, but the old row remains. What's wrong with my mapping XMLs ? Why NHibernate does not delete the old row before insert the new polymorphic object ?
Those are the mapping files I am using
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
namespace="SALClassLib.Masterdata.Model" assembly="SALClassLib">
<class name="Pessoa" table="TB_PESSOA">
<id name="Id">
<column name="ID_PESSOA" not-null="true"/>
<generator class="increment" />
</id>
(other properties...)
<joined-subclass name="PessoaFisica" table="TB_PESSOA_FISICA">
<key column="ID_PESSOA" />
(other properties...)
</joined-subclass>
<joined-subclass name="PessoaJuridica" table="TB_PESSOA_JURIDICA">
<key column="ID_PESSOA" />
(other properties...)
</joined-subclass>
</class>
<class name="Cliente" table="TB_CLIENTE">
<id name="Id">
<column name="ID_CLIENTE" not-null="true"/>
<generator class="increment" />
</id>
<many-to-one name="Pessoa" class="Pessoa" cascade="all" column="ID_PESSOA" not-null="true" unique="true" />
Thank you
NHibernate cascading is nicely explained here: NHibernate Cascades: the different between all, all-delete-orphans and save-update
One of the option, is cascade="all-delete-orphan" which could be seen as what you are asking for.
BUT
Cascading deletion of the orphans is correct only in parent-child scenario (no parent ==> no children) or one-to-one mapping. (i.e not vice versa child-parent)
In your case, you do ask for deletion of the referenced object. But NHibernate (well no-one) can know, if it is not referenced by some other "child".
If you need to delete previous Person assigned, you can always do it in code - but explicitly
I'm very new to NHibernate, and I'm running into a problem while saving a list of child objects.
NOTE
<class name="Note" table="NOTE">
<id name="NoteID" column="NOTE_ID">
<generator class="identity" />
</id>
...
<list name="Sections" table="NOTE_SECTIONS" cascade="all" lazy="false">
<key column="NOTE_ID"/>
<index column="SORT_ORDER"/>
<one-to-many class="Section"/>
</list>
</class>
NOTE SECTION
<class name="Section" table="NOTE_SECTIONS">
<id name="SectionID" column="Section_ID">
<generator class="identity" />
</id>
<property name="NoteID" column="NOTE_ID"/>
...
</class>
The mappings work perfectly for reading the data. However, when I make a change to the Note Section, The queries it generates appears to be going through the proper steps, but then I get the following error:
NHibernate.Exceptions.GenericADOException: could not delete collection: [Domain.Note.Sections#1][SQL: UPDATE NOTE_SECTIONS SET NOTE_ID = null, SORT_ORDER = null WHERE NOTE_ID = #p0] ---> System.Data.SqlClient.SqlException: Cannot insert the value NULL into column 'NOTE_ID', table 'NOTE_SECTIONS'; column does not allow nulls. UPDATE fails.
I have read that in order to save like this it will need to be bidirectional. But I've also read that bidrectional mappings don't work with Lists. It's important that my collection have a maintained order - what's the best way to save?
You should use inverse="true" on your collection mapping if you wish to save child objects in this manner.
<list name="Sections" table="NOTE_SECTIONS" inverse="true" cascade="all" lazy="false">
<key column="NOTE_ID"/>
<index column="SORT_ORDER"/>
<one-to-many class="Section"/>
</list>
Inverse Attribute in NHibernate
probably you would need to refer Note from Note Section as many-to-one relation.
I would love to thank #Stefan Steinegger and #David helped me out yesterday with many-to-many mapping.
I have 3 tables which are "News", "Tags" and "News_Tags" with Many-To-Many relationship and the "News_Tags" is the link table.
If I delete one of the news records, the following mappings will delete all my news records which have the same tags. One thing I need to notice, I only allowed unique tag stored in the "Tag" table.
This mapping make sense for me, it will delete the tag and related News records, but how can I implement a tagging system with NHibernate?
Can anyone give me some suggestion? Many thanks.
Daoming.
News Mapping:
<class name="New" table="News" lazy="false">
<id name="NewID">
<generator class="identity" />
</id>
<property name="Title" type="String"></property>
<property name="Description" type="String"></property>
<set name="TagsList" table="New_Tags" lazy="false" inverse="true" cascade="all">
<key column="NewID" />
<many-to-many class="Tag" column="TagID" />
</set>
</class>
Tag Mapping:
<class name="Tag" table="Tags" lazy="false">
<id name="TagID">
<generator class="identity" />
</id>
<property name="TagName" type="String"></property>
<property name="DateCreated" type="DateTime"></property>
<!--inverse="true" has been defined in the "News mapping"-->
<set name="NewsList" table="New_Tags" lazy="false" cascade="all">
<key column="TagID" />
<many-to-many class="New" column="NewID" />
</set>
</class>
When I run into trouble like that, the first thing I twiddle with is the cascade option.
As far as I know, the mapping is correct (I'm using mapping files that look exactly the same). The problem is the cascade attribute: the "all" option forces NHibernate to propagate each action on an entity to the instances of the collection. In your case, when you delete a news item all related tags are deleted too.
You probably should use "none" (in that case you'll eventually end up with some unused tags in the database) or "delete-orphans" (on the news item side - use "none" on the tag side).
Use the cascade option "save-update".
The option "all" will cascade deletes, which you do not want in this case. But you the option "none" will require that the Tag entity is already persisted which I guess might not always be the case.
So by setting the cascade to "save-update" new Tags till be inserted in the Tags table and in the link table News_Tags, but when you remove a tag from a News entity it will only be removed from the link table not the Tags table.
Hey all, I'm kicking the tires on NHibernate and have a conoundrum I have been scratching my head over for a bit now, working with a legacy database with some fairly complex relationships.
ClaimRoot has a primary key of a claimGUID.
ClaimRoot has a bag of Claimdetails associated by claimGUID (this works a treat).
The problem is that ClaimRoot also has an optional one to one relationship with ClaimFinancials (not all ClaimRoots have ClaimFinancials, but most do). But the PK for ClaimFinancials is a FormID field. This field exists in the ClaimRoot, but is not the PK.
I've posted a mapping below with extra columns removed to protect the innocent.
<class name="ClaimRoot" table="tbl_ClaimRoot" schema="DB1.dbo">
<id name="ClaimGUID">
<generator class="guid"/>
</id>
<property name="FormID" />
<property name="LastFormNoteText" />
<bag name="ClaimDetails" inverse="true">
<key column="ClaimGUID"/>
<one-to-many class="ClaimDetails"/>
</bag>
</class>
<class name="ClaimDetails" table="tbl_ClaimDetails" schema="DB2.dbo">
<id name="RowID">
<generator class="native"/>
</id>
<property name="ClaimGUID" />
<property name="SeqNo"/>
<property name="B1A_InsID" />
<many-to-one name="Root" column="ClaimGUID" foreign-key="ClaimGUID"/>
</class>
<class name="ClaimFinancials" table="tbl_ClaimFinancials" schema="DB1.dbo">
<id name="FormID">
<generator class="native"/>
</id>
<property name="CreatedDate"/>
<property name="SubmittedDate" />
</class>
Thanks in advance!
-Bob
Assuming the FormID is use only for linking ClaimRoot and ClaimFinancials, it sounds like you want a many-to-one relationship from ClaimRoot to ClaimFinancials. Replace the FormId property on ClaimRoot with a many-to-one.
<class name="ClaimRoot" table="tbl_ClaimRoot" schema="DB1.dbo">
...
<many-to-one name="ClaimFinancials" column="FormID" />
...
</class>
A many-to-one relationship can be be used even if there is only 'one' on the 'many' side. If you were generating a schema, you can specify unique="true" to generate the constraint in the database. With a legacy database, that won't matter.
Currently I have the following classes:
class Article with properties id, title and body
class Question : Article with an extra PostedBy property
Then I have a table called Article with the above properties and a table called questions with an ID a foreign key articleID and a PostedBy. Both are in different schemas
I would like to know how are my mappings going to look to represent this relation. Both classes are in different assemblies and i would be very reluctant to put Question logic in Article class/mapping and its assembly.
NHibernate supports three basic inheritance strategies.
table per class hierarchy
table per subclass
table per concrete class
It sounds like you are looking for the table per subclass strategy as you have a table for your Article class and another table for the extra properties on the Question subclass. The mapping might looks something like this:
<class name="Article" table="Article">
<id name="Id" type="Int64" column="ArticleId">
<generator class="native"/>
</id>
<property name="Title" column="Title"/>
<property name="Body" column="Body"/>
...
<joined-subclass name="Question" table="Question">
<key column="ArticleId"/>
<property name="PostedBy" column="PostedBy"/>
...
</joined-subclass>
</class>
However, this doesn't meet your desire to keep the mappings entirely separate. You could have entirely separate mappings, but this might have some side effects as allowing Question to be loaded as a plain Article instead of a Question. With separate mapping the Article class would be straight-forward as expected. The Question class would include a join to access the properties stored in the Article table.
<class name="Article" table="Article">
<id name="Id" type="Int64" column="ArticleId">
<generator class="native"/>
</id>
<property name="Title" column="Title"/>
<property name="Body" column="Body"/>
...
</class>
<class name="Question" table="Question">
<id name="Id" type="Int64" column="QuestionId">
<generator class="native"/>
</id>
<property name="PostedBy" column="PostedBy"/>
...
<join table="Article">
<key column="ArticleId"/>
<property name="Title" column="Title"/>
<property name="Body" column="Body"/>
</join>
</class>