NHibernate Many-to-many - nhibernate-mapping

I have a legacy database and I am trying to create a NHibernate DAL.
I have a problem with a mapping on Many-To-Many table.
The Database tables:
studio_Subscribers
studio_Groups (contains a IList of Subscribers)
studio_Subscribers_Groups - Many-To-Many table with primary keys
The problem is when I create a SubscriberGroup instance and fill it with Subscribers they gets saved to the studio_Subscribers table but not to the Many-To-Many table.
I cant figure out whats wrong?
studio_Subscribers table mapping:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
assembly="Meridix.Studio.Common"
namespace="Meridix.Studio.Common">
<class name="SubscriberItem" table="studio_Subscribers">
<id name="StorageId" column="Id" unsaved-value="0" access="nosetter.camelcase">
<generator class="identity" />
</id>
<property name="Id" column="DomainId" not-null="true" />
<property name="Subscriber" column="Subscriber" not-null="true" length="50" />
<property name="Description" column="Description" not-null="false" length="100" />
<property name="Type" column="Type" not-null="true" length="40"
type="Meridix.Studio.Data.Repositories.EnumStringTypes.SubscriberTypeEst, Meridix.Studio.Data.Repositories" />
</class>
</hibernate-mapping>
studio_Groups table mapping:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
assembly="Meridix.Studio.Common"
namespace="Meridix.Studio.Common">
<class name="SubscriberGroup" table="studio_Groups">
<id name="StorageId" column="Id" unsaved-value="0" access="nosetter.camelcase">
<generator class="identity" />
</id>
<property name="Id" column="DomainId" not-null="true" />
<property name="Name" column="Name" not-null="true" length="200" />
<property name="Description" column="Description" not-null="false" length="300" />
<bag name="Subscribers" table="studio_Groups_Subscribers" access="nosetter.camelcase">
<key column="GroupId"></key>
<many-to-many column="SubscriberId" class="SubscriberItem" />
</bag>
</class>
</hibernate-mapping>

Shouldn't you have an appropriate bag on your subscriber aswell with a many-to-many relation to the group?
<bag name="Groups" table="studio_Groups_Subscribers" access="nosetter.camelcase">
<key column="SubscriberId"></key>
<many-to-many column="GroupId" class="GroupItem" />
</bag>
and maybe have a cascade="save-update" on your SubscriberItems collection so that saving the Group will update your children with the appropriate relation from "the other side".

I believe it is to do with the cascade options, check out Ayende's post on it and I imagine with a bit of Googling you can find the correct syntax to go into your hbm file. I use fluent-NHibernate so I can't help you with the XML file.
http://ayende.com/Blog/archive/2006/12/02/NHibernateCascadesTheDifferentBetweenAllAlldeleteorphansAndSaveupdate.aspx

Related

NHibernate map a column to a property and a bag

I'm having some difficulties mapping the following sitation:
I have a person with a connection id, I use this to get map a bag and a property.
This works if the database already exists. But for our unit tests, we generate one from the schema, it gives an error : "duplicate column names".
Here is the mapping:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="DomainLayer.SearchDomain" assembly="Test">
<class name="SearchPerson" table="person" lazy="false" mutable="false">
<id name="Id" column="`id`" type="int">
<generator class="identity" />
</id>
<property name="Name" column="`NAAM`" type="string" />
<property name="FirstName" column="`VOORNAAM`" type="string" />
<property name="ConnectionId" column="`Koppelid`" type="int" />
<bag name="Languages" lazy="false" mutable="false" access="field.camelcase-underscore">
<key property-ref="ConnectionId" column="Koppelid" />
<one-to-many class="DomainLayer.Person.LanguageSkill, Test" />
</bag>
</class>
</hibernate-mapping>
Problem: "Koppelid" both in Key property from the bag as in the property.
Edit:
The LanguageSkill mapping:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="DomainLayer.Person" assembly="Test">
<class name="LanguageSkill" table="languageskill" lazy="false">
<id name="Id" type="Int32">
<generator class="identity" />
</id>
<property name="ConnectionId" column="`KoppelId`" type="Int64" />
<property name="Remark" column="`Opmerking`" type="string" />
<property name="Source" column="`CdOorsprong`" type="string" />
<property name="MotherTongue" column="`moedertaal`" type="boolean" />
<property name="ModifiedDate" column="`wyzdat`" type="DateTime" />
</class>
</hibernate-mapping>
It should actually work. It may be because you have marked it with ` in one case, but not in the other.
Try this:
<bag ...>
<key property-ref="ConnectionId" column="`Koppelid`" />
the reason is actually that the column is defined twice in the LanguageSkillMapping. Since you mapped the column you could map it as reference and set the bag to inverse
<bag name="Languages" inverse="true" lazy="false" mutable="false" access="field.camelcase-underscore">
<key property-ref="ConnectionId" column="Koppelid" />
<one-to-many class="DomainLayer.Person.LanguageSkill, Test" />
</bag>
<many-to-one name="SearchPerson" column="`KoppelId`" />
Update: nevermind, Stefan got it

Joining tables in NHibernate gets "collection element mapping has wrong number of columns"

I'm having trouble mapping a many-to-many relationship with a join table. The errror message I am getting is "collection element mapping has wrong number of columns"
My db schema is basically:
.
Despite the picture from SQL Server Management Studio, the database is Sqlite.
My mapping file is:
<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Design" table="Design">
<id name="DesignID" column="DesignID" type="Int32">
<generator class="native"/>
</id>
<property name="Name" type="String" column="Name" />
<property name="DisplayOrder" type="Int32" column="DisplayOrder" />
<property name="ChangeDate" column="ChangeDate" type="DateTime"/>
<set name="DesignMeasures" table="DesignProperties" cascade="save-update,delete-orphan" >
<key column="DesignID" />
<many-to-many column="PropertyID" class="DesignProperties" unique="true" />
</set>
</class>
<class name="Properties" table="Properties">
<id name="PropertyID" column="PropertyID" type="Int32">
<generator class="native" />
</id>
<property name="Name" type="String" column="Name" />
<property name="Value" type="String" column="Value" />
</class>
<class name="DesignProperties" table="DesignProperties">
<composite-id>
<key-many-to-one class="Design" name="DesignID" column="DesignID" />
<key-many-to-one class="Properties" name="PropertyID" column="PropertyID" />
</composite-id>
</class>
</hibernate-mapping>
I know I'm doing something wrong, but I can't figure it out. What am I doing wrong? How do I fix it?
DesignProperties is either a many-to-many relationship or an entity, not both.
Since it doesn't have any properties of its own, I'd remove the DesignProperties class along with its mapping, and just leave a collection of Property (not Properties; your class name should be singular) in Design.

Remove from one side of the many to many in Nhibernate

I have these 2 objects in NHibernate forming a many to many relationship:
User:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
assembly="Providers" namespace="Providers.Objects">
<class name="User" table="Users">
<id name="UserId" type="int">
<generator class="native" />
</id>
<many-to-one name="Application" column="ApplicationId" cascade="none" />
<property name="UserName" type="string" />
<property name="LoweredUserName" type="string" />
<property name="MobileAlias" type="string" />
<property name="IsAnonymous" type="bool" />
<property name="LastActivityDate" type="DateTime" />
<bag name="Roles" table="UsersInRoles" lazy="true" cascade="none" >
<key column="UserId"></key>
<many-to-many class="Role" column="RoleId"></many-to-many>
</bag>
</class>
</hibernate-mapping>
And Role:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
assembly="Providers" namespace="Providers.Objects">
<class name="Role" table="Roles">
<id name="RoleId" type="int">
<generator class="native" />
</id>
<many-to-one name="Application" column="ApplicationId" class="Application" cascade="none" />
<property name="RoleName" type="string" />
<property name="LoweredRoleName" type="string" />
<property name="Description" type="string" />
<bag name="Users" table="UsersInRoles" lazy="true" inverse="true" cascade="none" >
<key column="RoleId"></key>
<many-to-many class="User" column="UserId"></many-to-many>
</bag>
</class>
</hibernate-mapping>
Let's say the role backupoperator has some users in it. If I try to remove one of the users from the role instance, like:
var backupoperator = GetRoleByName(session, app.ApplicationId, "backupoperator");
backupoperator.Users.RemoveAt(0);
session.Update(backupoperator);
transaction.Commit();
It doesn't work :( The association remains unchanged in the database. When I try the opposite (remove a role from a user object and updating the user object), it works.
Is it because of the inverse attribute in the NHibernate mapping?
How to accomplish what I am trying to do? (remove a user from a role, updating the role and having that persisted)?
Thanks
When you write inverse="true" you are telling NHibernate that the other side maintains the relationship.
Therefore, you have to remove the Role from the User's Roles collection if you want your change persisted.

NHibernate map foreign key

I have two tables, Vehicle and Make. The two are joined using the MakeId as a foreign key on the Vehicle table. My mapping file looks similar to this
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Demo.Business.Objects.Vehicle, Demo.Business.Objects" table="Vehicle" >
<id name="VehicleId" type="int" >
<generator class="native" />
</id>
<property name="RegNumber" type="String" />
<property name="VehicleId" type="int" />
<property name="CustomerId" type="int" />
<join table="Make" fetch="join">
<key column="MakeId" foreign-key="MakeId"/>
<property name="Description" type="String" />
</join>
</class>
</hibernate-mapping>
I would have thought that this would join the two tables on the make id, however the SQL that ios generated tries the following join: vehicle.vehicleid = make.makeid.
How can I get this to work? I.e. I expect:
select * from Vehicle
inner join Make on Make.MakeId = Vehicle.Make Id
You need to map the Make class differently:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Demo.Business.Objects.Vehicle, Demo.Business.Objects" table="Vehicle" >
<id name="VehicleId" type="int" >
<generator class="native" />
</id>
<property name="RegNumber" type="String" />
<property name="VehicleId" type="int" />
<property name="CustomerId" type="int" />
<many-to-one name="Make" column="MakeId"/>
</class>
<class name="(blahblah).Make, blahblah">
<id name="MakeId" type="int">
<generator class="native" />
</id>
<property name="Description" type="String" />
</class>
</hibernate-mapping>
Your "Vehicle" class should have a Make property of type Make.

nhibernate newbe question ... easy one here

I'm new to nhibernate so this should be easy. I have a mapping file as below although I deleted some fields that aren't relevant to this question. The streamfields class contains a bag of fieldmappings. I want the join to be on field_no column but the sql that is sent is on the id field (str_fld_id") as seen below.
I see what the below sql is doing but it's not what I wanted. It's trying to query the field_mappings table based on the values found in the id column str_fld_id in the StreamFields class when I thought it was clear I wanted the field_no to be used on both ends. I say I thought it was clear because the mapping for the field_mapping class has the below attribute and they both have the same named field
Below is in my FieldMappings mapping file.
<many-to-one name="FieldNo" cascade="none" column="`Field_No`" not-null="true">
Sql sent
NHibernate: SELECT fkfieldmap0_.[field_no] as field5_1_, fkfieldmap0_.[Mapping_Id] as Mapping1_1_, fkfieldmap0_.[Mapping_Id] as Mapping1_3_0_, fkfieldmap0_.[Std_fld_Id] as Std2_3_0_, fkfieldmap0_.[Field_Position] as Field3_3_0_, fkfieldmap0_.[Field_No] as Field4_3_0_ FROM [Field_Mappings] fkfieldmap0_ WHERE fkfieldmap0_.[field_no]=#p0; #p0 = '20'
StreamFields mapping
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="DataTransfer.StreamFields,DataTransfer" table="`stream_fields`" lazy="true">
<id name="StrFldId" column="`str_fld_id`" type="int">
<generator class="native" />
</id>
<property type="int" not-null="true" name="FieldNo" column="`field_no`" />
<many-to-one name="StreamId" cascade="none" column="`stream_Id`" />
<bag name="FkFieldMappingsStreamFields" inverse="true" lazy="false" cascade="all">
<key column="`field_no`" />
<one-to-many class="DataTransfer.FieldMappings,DataTransfer"/>
</bag>
</class>
[Edited - with old comments]
Okay, i think i finally got you right and i might admit the problems i had understanding what you want took me a while and result of the lack of information you provided. In the future please provide the mapping of both tables clarify on the point wheather it is a mapping or a query issue. Thx.
IMO you have misunderstood the idea of a parent/child-relation.
The bag you mentioned like to have within the StreamFields class shouldn't be a bag but a direct association. Like this:
<class name="DataTransfer.StreamFields,DataTransfer" table="stream_fields" >
<id name="StrFldId" column="str_fld_id" type="int">
<generator class="native" />
</id>
<property type="int" not-null="true" name="FieldNo" column="field_no" />
<many-to-one name="FieldMapping" class="FiueldMapping" column="Field_No" />
</class>
This of course will only work if you have a property of type FiledMapping in your class.
You want to map FieldMapping to the column Field_No within StreamFields class. There can only be one value within this column, so a bag makes no sense at all. If you want to have a bag of course you can keep it the way it already worked but be aware that the 'key-column' within the bag refers to the child table - in an other way it makes no sense cause a ForeignKey has to map to a PrimaryKey on its parent table. This ensures it is unique and set.
I really don't want to rant but would strongly encourage you to review the hibernate reference about collection mapping to get a deeper clue however.
Hopely this will solve your problem.
Below are the mappings for the classes.
<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="DataTransfer.StreamFields,DataTransfer" table="`stream_fields`" lazy="true">
<id name="StrFldId" column="`str_fld_id`" type="int">
<generator class="native" />
</id>
<property type="string" length="50" name="FieldName" column="`field_name`" />
<property type="int" name="InputFieldPosition" column="`input_field_position`" />
<property type="int" name="Start" column="`start`" />
<property type="int" name="Width" column="`width`" />
<property type="string" length="50" name="Datatype" column="`datatype`" />
<property type="int" not-null="true" name="FieldNo" column="`field_no`" />
<property type="int" name="FieldOrder" column="`field_order`" />
<property type="int" name="StdId" column="`Std_Id`" />
<many-to-one name="StreamId" cascade="none" column="`stream_Id`" />
<bag name="FkFieldMappingsStreamFields" inverse="true" lazy="false" cascade="all">
<key column="`field_no`" />
<one-to-many class="DataTransfer.FieldMappings,DataTransfer"/>
</bag>
</class>
</hibernate-mapping>
<?xml version="1.0" encoding="utf-8"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="DataTransfer.FieldMappings,DataTransfer" table="`Field_Mappings`" lazy="false">
<id name="MappingId" column="`Mapping_Id`" type="int">
<generator class="native" />
</id>
<property type="int" name="StdFldId" column="`Std_fld_Id`" />
<property type="int" name="FieldPosition" column="`Field_Position`" />
<many-to-one name="FieldNo" cascade="none" column="`Field_No`" not-null="true" property-ref="FieldNo" />
</class>
</hibernate-mapping>
To make things easy on myself, there is one record in stream_fields and the field_no value is 1 and 20 is the value in StrFldId.
SELECT fkfieldmap0_.[field_no] as field5_1_, fkfieldmap0_.[Mapping_Id] as Mapping1_1_, fkfieldmap0_.[Mapping_Id] as Mapping1_3_0_, fkfieldmap0_.[Std_fld_Id] as Std2_3_0_, fkfieldmap0_.[Field_Position] as Field3_3_0_, fkfieldmap0_.[Field_No] as Field4_3_0_ FROM [Field_Mappings] fkfieldmap0_ WHERE fkfieldmap0_.[field_no]=#p0; #p0 = '20' –